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Sample records for aminoglycosides

  1. Pharmacokinetics of Aminoglycosides

    Institute of Scientific and Technical Information of China (English)

    Lokangu Lombo(Congo); HE Hua

    2004-01-01

    The Pharmacokinetics informations of aminoglycosides, their monograph and clinical Pharmacokinetics parameters are reported in this review. The Aminoglycosides are highly polarity and in reserve for serious infections caused by aerobic gram-negative bacteria and some gram-positive bacteria but their toxicity are major limitations in clinical use.

  2. Aminoglycosides: An Overview.

    Science.gov (United States)

    Krause, Kevin M; Serio, Alisa W; Kane, Timothy R; Connolly, Lynn E

    2016-01-01

    Aminoglycosides are natural or semisynthetic antibiotics derived from actinomycetes. They were among the first antibiotics to be introduced for routine clinical use and several examples have been approved for use in humans. They found widespread use as first-line agents in the early days of antimicrobial chemotherapy, but were eventually replaced in the 1980s with cephalosporins, carbapenems, and fluoroquinolones. Aminoglycosides synergize with a variety of other antibacterial classes, which, in combination with the continued increase in the rise of multidrug-resistant bacteria and the potential to improve the safety and efficacy of the class through optimized dosing regimens, has led to a renewed interest in these broad-spectrum and rapidly bactericidal antibacterials. PMID:27252397

  3. An aminoglycoside sensing riboswitch controls the expression of aminoglycoside resistance acetyltransferase and adenyltransferases.

    Science.gov (United States)

    Chen, Dongrong; Murchie, Alastair I H

    2014-10-01

    The emergence of antibiotic resistance in human pathogens is an increasing threat to public health. The fundamental mechanisms that control the high levels of expression of antibiotic resistance genes are not yet completely understood. The aminoglycosides are one of the earliest classes of antibiotics that were introduced in the 1940s. In the clinic aminoglycoside resistance is conferred most commonly through enzymatic modification of the drug although resistance through enzymatic modification of the target rRNA through methylation or the overexpression of efflux pumps is also appearing. An aminoglycoside sensing riboswitch has been identified that controls expression of the aminoglycoside resistance genes that encode the aminoglycoside acetyltransferase (AAC) and aminoglycoside nucleotidyltransferase (ANT) (adenyltransferase (AAD)) enzymes. AAC and ANT cause resistance to aminoglycoside antibiotics through modification of the drugs. Expression of the AAC and ANT resistance genes is regulated by aminoglycoside binding to the 5' leader RNA of the aac/aad genes. The aminoglycoside sensing RNA is also associated with the integron cassette system that captures antibiotic resistance genes. Specific aminoglycoside binding to the leader RNA induces a structural transition in the leader RNA, and consequently induction of resistance protein expression. Reporter gene expression, direct measurements of drug RNA binding, chemical probing and UV cross-linking combined with mutational analysis demonstrated that the leader RNA functioned as an aminoglycoside sensing riboswitch in which drug binding to the leader RNA leads to the induction of aminoglycoside antibiotic resistance. This article is part of a Special Issue entitled: Riboswitches. PMID:24631585

  4. Once-daily aminoglycoside therapy: potential ototoxicity.

    OpenAIRE

    Kirkpatrick, C. M.; Duffull, S. B.; Begg, E J

    1996-01-01

    Current data indicate that once-daily aminoglycoside therapy is as efficacious as traditional multiple daily dosing and equally or less toxic. Our experience with once-daily gentamicin, 6 mg/kg of body weight led to a 10% (3 of 33 patients) occurrence of documented ototoxicity after prolonged aminoglycoside exposure.

  5. Aminoglycoside resistance in clinical Gram-negative isolates from Norway

    OpenAIRE

    Haldorsen, Bjørg Christina

    2011-01-01

    Aminoglycosides represent an important class of antimicrobial agents. The prevalence of aminoglycoside resistance among Gram-negative bacteria in Norway is low, but an increased prevalence among clinical isolates of Escherichia coli has been observed during the last years. The most prevalent resistance mechanism is aminoglycoside modifying enzymes. In addition, resistance may occur when bacteria produces 16S rRNA methylases, which causes high level and broad-spectrum aminoglycoside resistance...

  6. Physiological and Molecular Pathology of Aminoglycoside Ototoxicity

    Science.gov (United States)

    Sha, Su-Hua

    2005-01-01

    The problem of aminoglycoside-induced ototoxicity, which was recognized within a year of the discovery of streptomycin to combat tuberculosis in 1944, is still of great concern due to the widespread use of these powerful antibacterial agents. These drugs can damage to varying degrees the cochlea and vestibular system. Their primary targets are the…

  7. DNA-Aptamers Binding Aminoglycoside Antibiotics

    Directory of Open Access Journals (Sweden)

    Nadia Nikolaus

    2014-02-01

    Full Text Available Aptamers are short, single stranded DNA or RNA oligonucleotides that are able to bind specifically and with high affinity to their non-nucleic acid target molecules. This binding reaction enables their application as biorecognition elements in biosensors and assays. As antibiotic residues pose a problem contributing to the emergence of antibiotic-resistant pathogens and thereby reducing the effectiveness of the drug to fight human infections, we selected aptamers targeted against the aminoglycoside antibiotic kanamycin A with the aim of constructing a robust and functional assay that can be used for water analysis. With this work we show that aptamers that were derived from a Capture-SELEX procedure targeting against kanamycin A also display binding to related aminoglycoside antibiotics. The binding patterns differ among all tested aptamers so that there are highly substance specific aptamers and more group specific aptamers binding to a different variety of aminoglycoside antibiotics. Also the region of the aminoglycoside antibiotics responsible for aptamer binding can be estimated. Affinities of the different aptamers for their target substance, kanamycin A, are measured with different approaches and are in the micromolar range. Finally, the proof of principle of an assay for detection of kanamycin A in a real water sample is given.

  8. Selective condensation of DNA by aminoglycoside antibiotics.

    Science.gov (United States)

    Kopaczynska, M; Schulz, A; Fraczkowska, K; Kraszewski, S; Podbielska, H; Fuhrhop, J H

    2016-05-01

    The condensing effect of aminoglycoside antibiotics on the structure of double-stranded DNA was examined. The selective condensation of DNA by small molecules is an interesting approach in biotechnology. Here, we present the interaction between calf thymus DNA and three types of antibiotic molecules: tobramycin, kanamycin, and neomycin. Several techniques were applied to study this effect. Atomic force microscopy, transmission electron microscopy images, and nuclear magnetic resonance spectra showed that the interaction of tobramycin with double-stranded DNA caused the rod, toroid, and sphere formation and very strong condensation of DNA strands, which was not observed in the case of other aminoglycosides used in the experiment. Studies on the mechanisms by which small molecules interact with DNA are important in understanding their functioning in cells, in designing new and efficient drugs, or in minimizing their adverse side effects. Specific interactions between tobramycin and DNA double helix was modeled using molecular dynamics simulations. Simulation study shows the aminoglycoside specificity to bend DNA double helix, shedding light on the origins of toroid formation. This phenomenon may lighten the ototoxicity or nephrotoxicity issues, but also other adverse reactions of aminoglycoside antibiotics in the human body. PMID:26646261

  9. Aminoglycoside resistance among isolates of nosocomial Enterobacteriaceae

    International Nuclear Information System (INIS)

    Fifty-seven gentamicin-resistant isolates of Enterobacteriaceae, obtained from patients attending hospital, were examined for the production of aminoglycoside-modifying enzymes. Of the 51 strains producing such enzymes, 34 were presumptively plasmid-mediated as indicated by conjugation experiments

  10. Modulation of RNA function by aminoglycoside antibiotics.

    Science.gov (United States)

    Schroeder, R; Waldsich, C; Wank, H

    2000-01-01

    One of the most important families of antibiotics are the aminoglycosides, including drugs such as neomycin B, paromomycin, gentamicin and streptomycin. With the discovery of the catalytic potential of RNA, these antibiotics became very popular due to their RNA-binding capacity. They serve for the analysis of RNA function as well as for the study of RNA as a potential therapeutic target. Improvements in RNA structure determination recently provided first insights into the decoding site of the ribosome at high resolution and how aminoglycosides might induce misreading of the genetic code. In addition to inhibiting prokaryotic translation, aminoglycosides inhibit several catalytic RNAs such as self-splicing group I introns, RNase P and small ribozymes in vitro. Furthermore, these antibiotics interfere with human immunodeficiency virus (HIV) replication by disrupting essential RNA-protein contacts. Most exciting is the potential of many RNA-binding antibiotics to stimulate RNA activities, conceiving small-molecule partners for the hypothesis of an ancient RNA world. SELEX (systematic evolution of ligands by exponential enrichment) has been used in this evolutionary game leading to small synthetic RNAs, whose NMR structures gave valuable information on how aminoglycosides interact with RNA, which could possibly be used in applied science. PMID:10619838

  11. Modulation of RNA function by aminoglycoside antibiotics.

    OpenAIRE

    Schroeder, R; Waldsich, C; Wank, H

    2000-01-01

    One of the most important families of antibiotics are the aminoglycosides, including drugs such as neomycin B, paromomycin, gentamicin and streptomycin. With the discovery of the catalytic potential of RNA, these antibiotics became very popular due to their RNA-binding capacity. They serve for the analysis of RNA function as well as for the study of RNA as a potential therapeutic target. Improvements in RNA structure determination recently provided first insights into the decoding site of the...

  12. Aminoglycoside antibiotics and autism: a speculative hypothesis

    Directory of Open Access Journals (Sweden)

    Manev Hari

    2001-10-01

    Full Text Available Abstract Background Recently, it has been suspected that there is a relationship between therapy with some antibiotics and the onset of autism; but even more curious, some children benefited transiently from a subsequent treatment with a different antibiotic. Here, we speculate how aminoglycoside antibiotics might be associated with autism. Presentation We hypothesize that aminoglycoside antibiotics could a trigger the autism syndrome in susceptible infants by causing the stop codon readthrough, i.e., a misreading of the genetic code of a hypothetical critical gene, and/or b improve autism symptoms by correcting the premature stop codon mutation in a hypothetical polymorphic gene linked to autism. Testing Investigate, retrospectively, whether a link exists between aminoglycoside use (which is not extensive in children and the onset of autism symptoms (hypothesis "a", or between amino glycoside use and improvement of these symptoms (hypothesis "b". Whereas a prospective study to test hypothesis "a" is not ethically justifiable, a study could be designed to test hypothesis "b". Implications It should be stressed that at this stage no direct evidence supports our speculative hypothesis and that its main purpose is to initiate development of new ideas that, eventually, would improve our understanding of the pathobiology of autism.

  13. Chronopharmacokinetics of once daily dosed aminoglycosides in hospitalized infectious patients

    OpenAIRE

    van Maarseveen, Erik; Man, Wai Hong; Proost, Johannes; Neef, Cees; Touw, Daniël

    2015-01-01

    Background hospitalized patients with serious infections treated with aminoglycosides are at risk of developing nephrotoxicity. Previous clinical studies have shown that the pharmacokinetics of aminoglycosides in humans follow a circadian rhythm. Therefore, the time of administration could have important clinical implications with respect to the risk of developing aminoglycoside-associated nephrotoxicity in patients treated with once daily dosing regimens. Objective To examine the effect of t...

  14. Extracellular DNA Shields against Aminoglycosides in Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Nilsson, Martin; Jensen, Peter Østrup;

    2013-01-01

    Within recent years, it has been established that extracellular DNA is a key constituent of the matrix of microbial biofilms. In addition, it has recently been demonstrated that DNA binds positively charged antimicrobials such as aminoglycosides and antimicrobial peptides. In the present study, we...... provide evidence that extracellular DNA shields against aminoglycosides in Pseudomonas aeruginosa biofilms. We show that exogenously supplemented DNA integrates into P. aeruginosa biofilms and increases their tolerance toward aminoglycosides. We provide evidence that biofilms formed by a DNA release......-deficient P. aeruginosa quorum-sensing mutant are more susceptible to aminoglycoside treatment than wild-type biofilms but become rescued from the detrimental action of aminoglycosides upon supplementation with exogenous DNA. Furthermore, we demonstrate that exposure to lysed polymorphonuclear leukocytes...

  15. Microplate phosphocellulose binding assay for aminoglycoside-modifying enzymes.

    OpenAIRE

    Cooksey, R C; Metchock, B G; Thornsberry, C

    1986-01-01

    We modified the phosphocellulose binding assay for aminoglycoside-modifying enzymes (AMEs) by use of microdilution plates and a multichannel micropipette. Batteries of aminoglycoside substrates for screening organisms for the presence of AMEs as well as for subclassifying enzymes were prepared and stored in microdilution plates. When tested in parallel with the conventional tube reaction assay, the microplate assay yielded comparable radioactive counts and therefore equally correct identifica...

  16. High throughput LSPR and SERS analysis of aminoglycoside antibiotics.

    Science.gov (United States)

    McKeating, Kristy S; Couture, Maxime; Dinel, Marie-Pier; Garneau-Tsodikova, Sylvie; Masson, Jean-Francois

    2016-08-15

    Aminoglycoside antibiotics are used in the treatment of infections caused by Gram-negative bacteria, and are often dispensed only in severe cases due to their adverse side effects. Patients undergoing treatment with these antibiotics are therefore commonly subjected to therapeutic drug monitoring (TDM) to ensure a safe and effective personalised dosage. The ability to detect these antibiotics in a rapid and sensitive manner in human fluids is therefore of the utmost importance in order to provide effective monitoring of these drugs, which could potentially allow for a more widespread use of this class of antibiotics. Herein, we report on the detection of various aminoglycosides, by exploiting their ability to aggregate gold nanoparticles. The number and position of the amino groups of aminoglycoside antibiotics controlled the aggregation process. We investigated the complementary techniques of surface enhanced Raman spectroscopy (SERS) and localized surface plasmon resonance (LSPR) for dual detection of these aminoglycoside antibiotics and performed an in-depth study of the feasibility of carrying out TDM of tobramycin using a platform amenable to high throughput analysis. Herein, we also demonstrate dual detection of tobramycin using both LSPR and SERS in a single platform and within the clinically relevant concentration range needed for TDM of this particular aminoglycoside. Additionally we provide evidence that tobramycin can be detected in spiked human serum using only functionalised nanoparticles and SERS analysis. PMID:27412506

  17. Radioenzymatic assays for aminoglycosides with kanamycin 6'- acetyltransferase

    International Nuclear Information System (INIS)

    To facilitate the rapid and accurate quantitation of parenterally administered aminoglycosides, the optimum conditions (pH, duration of incubation, and cofactor concentrations) were defined to permit radioenzymatic assays with kanamycin acetyltransferase. The accuracy in quantitating tobramycin, netilmicin, kanamycin, and amikacin at concentrations in the therapeutic range was greater than 90%, with a mean recovery of 102.8%. The mean of the interassay coefficient of variation was 7.8%. Typical standard curves at six different concentrations resulted in a correlation coefficient (r value) of greater than 0.99 for each aminoglycoside. The radioenzymatic assay correlates well with the bioassay (tobramycin and netilmicin) and radioimmunoassay (amikacin and kanamycin); the correlation coefficient is greater than 0.90 for all. The authors conclude that the radioenzymatic assay utilizing kanamycin 6'-acetyltransferase is feasible for all commercially available parenterally administered aminoglycosides

  18. Genetic basis of aminoglycoside resistance following changes in aminoglycoside prescription patterns.

    Science.gov (United States)

    Kosmidis, Chris; Giannopoulou, Maria; Flountzi, Anastasia; Markogiannakis, Antonis; Goukos, Dimitris; Petrikkos, George; Daikos, George L; Tzanetou, Konstantina

    2013-08-01

    Aminoglycosides (AG) offer an important therapeutic option for the treatment of infections caused by multiresistant Enterobacteriaceae. We observed a change in AG usage patterns in our institution between 1997 and 2006, namely a reduction in use of all AG except amikacin. We studied the changes in AG susceptibility rates in these time periods and correlated with prevalence of different molecular resistance mechanisms. Enterobacteriaceae isolated from blood cultures from 1997 and 2006 were studied. Susceptibilities to AG were determined with the disk diffusion method. PCR was used to detect genes encoding AG-modifying enzymes and methylases. Gentamicin resistance rates dropped from 14·5 to 8·8%, whereas resistance rates to other AG remained unchanged. The AAC(6')-I+AAC(3)-I combination was more common in 1997, whereas AAC(6')-I was the most common mechanism in 2006. Reduction in gentamicin use may preserve the usefulness of this agent against severe infections by multiresistant bacteria such as carbapenemase-producing Enterobacteriaceae. PMID:23906075

  19. Radioenzymatic assays for aminoglycosides with kanamycin 6'-acetyltransferase.

    OpenAIRE

    Weber, A; Smith, A L; Opheim, K E

    1985-01-01

    To facilitate the rapid and accurate quantitation of parenterally administered aminoglycosides, we defined the optimum conditions (pH, duration of incubation, and cofactor concentrations) to permit radioenzymatic assays with kanamycin acetyltransferase. The accuracy in quantitating tobramycin, netilmicin, kanamycin, and amikacin at concentrations in the therapeutic range was greater than 90%, with a mean recovery of 102.8%. The mean of the interassay coefficient of variation was 7.8%. Typical...

  20. DETERMINATION OF AMINOGLYCOSIDES IN FOOD BY FLUORESCENCE POLARIZATION IMMUNOASSAY

    Directory of Open Access Journals (Sweden)

    FARAFONOVA O.V.

    2015-01-01

    Full Text Available The methodic for quantitative determination of aminoglycoside antibiotics (gentamicin, kanamycin, streptomycin, amikacin, neomycin in food by polarization fluorescent immunoassay (FPIA is developed. The size and structure influence of a fluorescent molecule on a fluorescence polarization degree is analyzed. Affinity constants of antibodies to compounds and tracers were estimated, optimized working concentration of tracers and antibodies that provide the maximum value of analytical signal. Methods were tested in the antibiotics identification in milk, eggs and chicken.

  1. UK31214, a new aminoglycoside and derivative of kanamycin B.

    OpenAIRE

    Wise, R.; Andrews, J. M.; Bedford, K A

    1980-01-01

    The in vitro activity of UK31214, a kanamycin B derivative, was studied against 250 recent isolates and compared with other aminoglycosides. Against the Enterobacteriaceae (with the exception of Proteus mirabilis and Providencia stuartii) UK31214 and amikacin had similar degrees of activity (mode minimum inhibitory concentration [MIC], 1 microgram/ml). Proteus mirabilis and P. stuartii strains were four- to eight-fold more susceptible to amikacin than to UK31214. Pseudomonas aeruginosa strain...

  2. Determination of aminoglycoside resistance in Staphylococcus aureus by DNA hybridization.

    OpenAIRE

    Dickgiesser, N; Kreiswirth, B N

    1986-01-01

    A method is described for identification of the genes conferring aminoglycoside resistance in Staphylococcus aureus by dot-blot and Southern blot techniques. As radioactive probes, fragments of plasmids pAT48, pUBH2, and pH13, carrying the genes for an aminocyclitol-3'-phosphotransferase, an aminocyclitol-4'-adenylyltransferase, and an aminocyclitol-2''-phosphotransferase-aminocyclitol-6'-acetyltransferase, respectively, were used.

  3. Antifungal amphiphilic aminoglycoside K20: bioactivities and mechanism of action

    OpenAIRE

    Shrestha, Sanjib K.; Cheng-Wei T Chang; Meissner, Nicole; Oblad, John; Shrestha, Jaya P.; Sorensen, Kevin N.; Michelle M. Grilley; Jon Y Takemoto

    2014-01-01

    K20 is a novel amphiphilic antifungal aminoglycoside that is synthetically derived from the antibiotic kanamycin A. Reported here are investigations of K20′s antimicrobial activities, cytotoxicity, and fungicidal mechanism of action. In vitro growth inhibitory activities against a variety of human and plant pathogenic yeasts, filamentous fungi, and bacteria were determined using microbroth dilution assays and time-kill curve analyses, and hemolytic and animal cell cytotoxic activities were de...

  4. Antifungal amphiphilic aminoglycoside K20: bioactivities and mechanism of action

    OpenAIRE

    Shrestha, Sanjib K.; Cheng-Wei Tom Chang; Nicole eMeissner; John eOblad; Shrestha, Jaya P.; Sorensen, Kevin N.; Michelle M. Grilley; Jon Y Takemoto

    2014-01-01

    K20 is a novel amphiphilic antifungal aminoglycoside that is synthetically derived from the antibiotic kanamycin A. Reported here are investigations of K20’s antimicrobial activities, cytotoxicity, and fungicidal mechanism of action. In vitro growth inhibitory activities against a variety of human and plant pathogenic yeasts, filamentous fungi, and bacteria were determined using microbroth dilution assays and time-kill curve analyses, and hemolytic and animal cell cytotoxic activities were d...

  5. The effect of pharmacy intervention on aminoglycoside costs.

    Science.gov (United States)

    Tsuyuki, R T; Nakagawa, R S

    1987-04-01

    Antibiotics constitute a large percentage of every hospital's drug budget. In an effort to control the escalating costs of antimicrobial therapy, we focused on the usage of aminoglycosides at our institution. The aminoglycosides, gentamicin and tobramycin, are similar in terms of antimicrobial spectra and toxicities. Since gentamicin is much less expensive, it was felt that significant cost savings would be realized if gentamicin were to be used preferentially over tobramycin. Specific criteria for the use of tobramycin were developed and approved by the Pharmacy and Therapeutics Committee. All patients prescribed parenteral tobramycin during the five week data collection period were entered into the study. We chose to use direct verbal intervention as our method for altering physician's prescribing patterns. An educational program of intervention was set up such that when a physician prescribed tobramycin, the patient's chart was immediately reviewed. If tobramycin was prescribed for a purpose other than those in the approved criteria for tobramycin use, the physician was contacted personally to discuss the cost-effectiveness of gentamicin use. Utilization figures from the previous six months showed that our interventions would save approximately $32,000 over a one year period. Our interventions on aminoglycoside prescribing represents a highly successful, cost-effective and educational method for altering physician's prescribing patterns. PMID:10282090

  6. 16S ribosomal RNA methylation: emerging resistance mechanism against aminoglycosides.

    Science.gov (United States)

    Doi, Yohei; Arakawa, Yoshichika

    2007-07-01

    Methylation of 16S ribosomal RNA (rRNA) has recently emerged as a new mechanism of resistance against aminoglycosides among gram-negative pathogens belonging to the family Enterobacteriaceae and glucose-nonfermentative microbes, including Pseudomonas aeruginosa and Acinetobacter species. This event is mediated by a newly recognized group of 16S rRNA methylases, which share modest similarity to those produced by aminoglycoside-producing actinomycetes. Their presence confers a high level of resistance to all parenterally administered aminoglycosides that are currently in clinical use. The responsible genes are mostly located on transposons within transferable plasmids, which provides them with the potential to spread horizontally and may in part explain the already worldwide distribution of this novel resistance mechanism. Some of these organisms have been found to coproduce extended-spectrum beta-lactamases or metallo-beta-lactamases, contributing to their multidrug-resistant phenotypes. A 2-tiered approach, consisting of disk diffusion tests followed by confirmation with polymerase chain reaction, is recommended for detection of 16S rRNA methylase-mediated resistance. PMID:17554708

  7. Synergistic effect of [10]-gingerol and aminoglycosides against vancomycin-resistant enterococci (VRE).

    Science.gov (United States)

    Nagoshi, Chihiro; Shiota, Sumiko; Kuroda, Teruo; Hatano, Tsutomu; Yoshida, Takashi; Kariyama, Reiko; Tsuchiya, Tomofusa

    2006-03-01

    An extract from ginger (root of Zingiber officinale) reduced the minimum inhibitory concentrations (MICs) of aminoglycosides in vancomycin-resistant enterococci (VRE). The effective compound was isolated and identified as [10]-gingerol. In the presence of [10]-gingerol at 1/10 concentration of its own MIC, the MIC of arbekacin was lowered by 1/32 to 1/16. [10]-Gingerol also reduced the MICs of other aminoglycosides, and of bacitracin and polymixin B, but not of other antimicrobial agents tested. Because [10]-gingerol reduced the MICs of several aminoglycosides both in strains possessing or lacking aminoglycoside-modification enzymes, it seems that the effect of [10]-gingerol is not related to these enzymes, which mainly confer bacterial resistance against aminoglycosides. It seemed that a detergent-like effect of [10]-gingerol potentiated the antimicrobial activity of the aminoglycosides. In fact, some detergents such as sodium dodecyl sulfate (SDS) and Triton X-100 reduced the MICs of aminoglycosides, bacitracin and polymixin B in VRE. Since the intrinsic resistance to aminoglycosides in enterococci is due to low level of entry of the drugs into the cells, increase in the membrane permeability caused by [10]-gingerol will enhance the influx of aminoglycosides into enterococcal cells. PMID:16508142

  8. Chaperonins fight aminoglycoside-induced protein misfolding and promote short-term tolerance in Escherichia coli

    DEFF Research Database (Denmark)

    Goltermann, Lise; Good, Liam; Bentin, Thomas

    2013-01-01

    survival, whereas inhibition of chaperonin expression sensitized bacteria. Overexpression of the DnaK/DnaJ/GrpE chaperone system similarly facilitated survival but did not promote growth of aminoglycoside-treated bacteria. Inhibition of chaperonin expression sensitized bacteria to aminoglycosides as...

  9. Aminoglycoside-derived amphiphilic nanoparticles for molecular delivery.

    Science.gov (United States)

    Miryala, Bhavani; Godeshala, Sudhakar; Grandhi, Taraka Sai Pavan; Christensen, Matthew D; Tian, Yanqing; Rege, Kaushal

    2016-10-01

    The development of effective drug carriers can lead to improved outcomes in a variety of disease conditions. Aminoglycosides have been used as antibacterial therapeutics, and are attractive as monomers for the development of polymeric materials in various applications. Here, we describe the development of novel aminoglycoside-derived amphiphilic nanoparticles for drug delivery, with an eye towards ablation of cancer cells. The aminoglycoside paromomycin was first cross-linked with resorcinol diglycidyl ether leading to the formation of a poly (amino ether), PAE. PAE molecules were further derivatized with methoxy-terminated poly(ethylene glycol) or mPEG resulting in the formation of mPEG-PAE polymer, which self-assembled to form nanoparticles. Formation of the mPEG-PAE amphiphile was characterized using (1)H NMR, (13)C NMR, gel permeation chromatography (GPC) and FTIR spectroscopy. Self-assembly of the polymer into nanoparticles was characterized using dynamic light scattering, zeta potential analyses, atomic force microscopy (AFM) and the pyrene fluorescence assay. mPEG-PAE nanoparticles were able to carry significant amounts of doxorubicin (DOX), presumably by means of hydrophobic interactions between the drug and the core. Cell-based studies indicated that mPEG-PAE nanoparticles, loaded with doxorubicin, were able to induce significant loss in viabilities of PC3 human prostate cancer, MDA-MB-231 human breast cancer, and MB49 murine bladder cancer cells; empty nanoparticles resulted in negligible losses of cell viability under the conditions investigated. Taken together, our results indicate that the mPEG-PAE nanoparticle platform is attractive for drug delivery in different applications, including cancer. PMID:27472455

  10. Deciphering the details of RNA aminoglycoside interactions: from atomistic models to biotechnological applications

    Energy Technology Data Exchange (ETDEWEB)

    Ilgu, Muslum [Iowa State Univ., Ames, IA (United States)

    2012-01-01

    A detailed study was done of the neomycin-B RNA aptamer for determining its selectivity and binding ability to both neomycin– and kanamycin-class aminoglycosides. A novel method to increase drug concentrations in cells for more efficiently killing is described. To test the method, a bacterial model system was adopted and several small RNA molecules interacting with aminoglycosides were cloned downstream of T7 RNA polymerase promoter in an expression vector. Then, the growth analysis of E. coli expressing aptamers was observed for 12-hour period. Our analysis indicated that aptamers helped to increase the intracellular concentration of aminoglycosides thereby increasing their efficacy.

  11. Cp*Rh-based indicator-displacement assays for the identification of amino sugars and aminoglycosides.

    Science.gov (United States)

    Zaubitzer, Friederike; Buryak, Andrey; Severin, Kay

    2006-05-01

    Indicator-displacement assays based on the organometallic complex [{Cp*RhCl2}2] (Cp*=pentamethylcyclopentadienyl) and the dye gallocyanine were used to sense amino sugars and aminoglycosides in buffered aqueous solution by conducting UV-visible spectroscopy. The data of three assays at pH 7.0, 8.0, and 9.0 were sufficient to distinguish between the amino sugars galactosamine, glucosamine, mannosamine and the aminoglycosides kanamycin A, kanamycin B, amikacin, apramycin, paromomycin, and streptomycin. Furthermore, the assays were used to characterize mixtures of aminoglycosides and obtain quantitative information about the respective analytes. PMID:16521137

  12. Study of Pseudomonas Aeroginosa resistance to Penicillines, Cephalosporins and Aminoglycosides

    Directory of Open Access Journals (Sweden)

    Maleknezhad P

    1998-07-01

    Full Text Available Drug therapy and prophylaxy in infectious diseases, from hygienic and economical point of view, are very important. Infections caused by pseudomonas aeroginosa were particularly severe, with high mortality rates. In the recent years pseudomonas aeroginosa continued to cause the most severe, life-thereating infections in burned patients, in spite of the introduction of a wide variety of antibiotics advised specifically for their anti pseudomonal activity. The aim of this study, in which many cases of ps.aeroginosa infections are assessed is to identify the drug resistance of this bacteria to penicillines, cephalosporins and aminoglycosides by antibiotic sensitivity test (disk ager diffusion. Results as percent of resistance to each antibiotic were 89% to carbenicillin, 55% to piperacillin, 89% to mezlocillin, 89.5% to ticarcillin+clavulonic acid, 85% to ceftriaxone, 95% to tobramycin, 5% of all isolates were not sensitive to any antibiotics.

  13. Antifungal amphiphilic aminoglycoside K20: bioactivities and mechanism of action

    Directory of Open Access Journals (Sweden)

    Sanjib K. Shrestha

    2014-12-01

    Full Text Available K20 is a novel amphiphilic antifungal aminoglycoside that is synthetically derived from the antibiotic kanamycin A. Reported here are investigations of K20’s antimicrobial activities, cytotoxicity, and fungicidal mechanism of action. In vitro growth inhibitory activities against a variety of human and plant pathogenic yeasts, filamentous fungi, and bacteria were determined using microbroth dilution assays and time-kill curve analyses, and hemolytic and animal cell cytotoxic activities were determined. Effects on Cryptococcus neoformans H-99 infectivity were determined with a preventive murine lung infection model. The antifungal mechanism of action was studied using intact fungal cells, yeast lipid mutants, and small unilamellar lipid vesicles. K20 exhibited broad-spectrum in vitro antifungal activities but not antibacterial activities. Pulmonary, single dose-administration of K20 reduced C. neoformans lung infection rates 4-fold compared to controls. Hemolysis and half-maximal cytotoxicities of mammalian cells occurred at concentrations that were 10 to 32-fold higher than fungicidal MICs. With fluorescein isothiocyanate, 20 to 25 mg/L K20 caused staining of >95% of C. neoformans and Fusarium graminearum cells and at 31.3 mg/L caused rapid leakage (30 to 80% in 15 min of calcein from preloaded small unilamellar lipid vesicles. K20 appears to be a broad-spectrum fungicide, capable of reducing the infectivity of C. neoformans, and exhibits low hemolytic activity and mammalian cell toxicity. It perturbs the plasma membrane by mechanisms that are lipid modulated. K20 is a novel amphiphilic aminoglycoside amenable to scalable production and a potential lead antifungal for therapeutic and crop protection applications.

  14. Emerging resistance to aminoglycosides in lactic acid bacteria of food origin-an impending menace.

    Science.gov (United States)

    Jaimee, G; Halami, P M

    2016-02-01

    Aminoglycosides are the most preferred choice of therapy against serious infections in humans. Therefore, its use in animal husbandry has been strictly regulated in the EU, UK, and USA to avoid the hazards of aminoglycoside resistance in gut microflora. Nevertheless, aminoglycosides are recommended for prophylaxis and therapeutics in food animals and agriculture owing to its bactericidal nature. In the recent past, the global surge in aminoglycoside-resistant lactic acid bacteria (LAB) from food sources has been noticed that might question its continued use in animal husbandry. Upon antibiotic administration, a selective pressure is created in the gut environment; in such instances, LAB could act as reservoirs of antibiotic resistance which may facilitate their transfer to pathogenic organisms contradicting its probiotic and industrial significance. This may be a risk to human health as the presence of one aminoglycoside resistance gene renders the bacteria tolerant to almost all antibiotics of the same class, thereby challenging its therapeutic efficacy. Low doses of aminoglycosides are recommended in farm animals due to its toxic nature and insolubility in blood. However, recent investigations indicate that use of aminoglycosides in sub-lethal concentrations can trigger the selection and conjugal transfer of aminoglycoside resistance in probiotic LAB. Resistance to erythromycin, tetracyclines, and fluoroquinolones in LAB were reported earlier to which immediate regulatory measures were adopted by some countries. Paradoxically, lack of regulations on antibiotic use in farms in most developing countries makes them a potential source of antibiotic resistance and its uncontrolled spread around the globe. The prevalence of aminoglycoside resistance was observed in enterococci from food origin earlier; however, its emergence in lactobacilli and pediococci suggests its spread in probiotic cultures which prompts immediate precautionary methods. This review highlights the

  15. Sensitivity of ribosomes of the hyperthermophilic bacterium Aquifex pyrophilus to aminoglycoside antibiotics.

    OpenAIRE

    Bocchetta, M; Huber, R.; Cammarano, P

    1996-01-01

    A poly(U)-programmed cell-free system from the hyperthermophilic bacterium Aquifex pyrophilus has been developed, and the susceptibility of Aquifex ribosomes to the miscoding-inducing and inhibitory actions of all known classes of aminoglycoside antibiotics has been assayed at temperatures (75 to 80 degrees C) close to the physiological optimum for cell growth. Unlike Thermotoga maritima ribosomes, which are systematically refractory to all known classes of aminoglycoside compounds (P. Londei...

  16. Toggled RNA Aptamers Against Aminoglycosides Allowing Facile Detection of Antibiotics Using Gold Nanoparticle Assays

    OpenAIRE

    Derbyshire, Nicola; White, Simon J.; Bunka, David H. J.; Song, Lei; Stead, Sara; Tarbin, Jonathan; Sharman, Matthew; Zhou, Dejian; Stockley, Peter G.

    2012-01-01

    We have used systematic evolution of ligands by exponential enrichment (SELEX) to isolate RNA aptamers against aminoglycoside antibiotics. The SELEX rounds were toggled against four pairs of aminoglycosides with the goal of isolating reagents that recognize conserved structural features. The resulting aptamers bind both of their selection targets with nanomolar affinities. They also bind the less structurally related targets, although they show clear specificity for this class of antibiotics....

  17. Determination of aminoglycoside antibiotics using complex compounds of chromotropic acid bisazoderivatives with rare earth ions

    International Nuclear Information System (INIS)

    Studies of complex formation of bisazo derivatives of chromotropic acid with rare earth ions and aminoglycoside antibiotics have made it possible to choose carboxyarsenazo, orthanyl R and carboxynitrazo as highly sensitive reagents for determining aminoglycoside antibiotics. Conditions have been found for the formation of precipitates of different-ligand complexes containing rare earth ions, bisazo derivatives of chromotropic acid and aminogylcoside antibiotics. A procedure has been worked out of determining the antibiotics in biological samples with carboxyarsenazo

  18. Once Daily Dosing of Aminoglycosides in Pediatric Cystic Fibrosis Patients: A Review of the Literature

    OpenAIRE

    Wassil, Sarah K.; Fox, Kristie M.; White, James W.

    2008-01-01

    Patients with cystic fibrosis receive many courses of antibiotic therapy throughout their lifetime. Dosing aminoglycosides once daily has become common practice in many of these individuals. Due to ease of home administration, decreased nursing time, and improved quality of life, this regimen is being increasingly explored in the cystic fibrosis population. Because patients with cystic fibrosis have increased aminoglycoside clearance, once daily dosing may result in a prolonged time during th...

  19. The aac(6'Ib gene in Proteus mirabilis strains resistant to aminoglycosides.

    Directory of Open Access Journals (Sweden)

    Jerzy Ratajczak

    2009-01-01

    Full Text Available The aim of this study was to evaluate the presence of aac(6'-Ib gene conferring resistance to aminoglycosides in Proteus mirabilis strains. Five isolates had aac(6'-Ib gene. In one case the gene was no-expressed. Three isolates were resistant to all aminoglycosides and minimum inhibitory concentrations were > or = 256 microg/ml. Additionally, all positive strains were resistant to tetracycline and ciprofloxacin.

  20. Mechanism of Enhanced Activity of Liposome-Entrapped Aminoglycosides against Resistant Strains of Pseudomonas aeruginosa

    OpenAIRE

    Mugabe, Clement; Halwani, Majed; Azghani, Ali O.; Lafrenie, Robert M.; Omri, Abdelwahab

    2006-01-01

    Pseudomonas aeruginosa is inherently resistant to most conventional antibiotics. The mechanism of resistance of this bacterium is mainly associated with the low permeability of its outer membrane to these agents. We sought to assess the bactericidal efficacy of liposome-entrapped aminoglycosides against resistant clinical strains of P. aeruginosa and to define the mechanism of liposome-bacterium interactions. Aminoglycosides were incorporated into liposomes, and the bactericidal efficacies of...

  1. Strategies to overcome the action of aminoglycoside-modifying enzymes for treating resistant bacterial infections

    OpenAIRE

    Labby, Kristin J.; Garneau-Tsodikova, Sylvie

    2013-01-01

    Shortly after the discovery of the first antibiotics, bacterial resistance began to emerge. Many mechanisms give rise to resistance; the most prevalent mechanism of resistance to the aminoglycoside (AG) family of antibiotics is the action of aminoglycoside-modifying enzymes (AMEs). Since the identification of these modifying enzymes, many efforts have been put forth to prevent their damaging alterations of AGs. These diverse strategies are discussed within this review, including: creating new...

  2. Aminoglycoside microarrays to explore interactions of antibiotics with RNAs and proteins.

    Science.gov (United States)

    Disney, Matthew D; Seeberger, Peter H

    2004-07-01

    RNA is an important target for drug discovery efforts. Several clinically used aminoglycoside antibiotics bind to bacterial rRNA and inhibit protein synthesis. Aminoglycosides, however, are losing efficacy due to their inherent toxicity and the increase in antibiotic resistance. Targeting of other RNAs is also becoming more attractive thanks to the discovery of new potential RNA drug targets through genome sequencing and biochemical efforts. Identification of new compounds that target RNA is therefore urgent, and we report here on the development of rapid screening methods to probe binding of low molecular weight ligands to proteins and RNAs. A series of aminoglycosides has been immobilized onto glass microscope slides, and binding to proteins and RNAs has been detected by fluorescence. Construction and analysis of the arrays is completed by standard DNA genechip technology. Binding of immobilized aminoglycosides to proteins that are models for study of aminoglycoside toxicity (DNA polymerase and phospholipase C), small RNA oligonucleotide mimics of aminoglycoside binding sites in the ribosome (rRNA A-site mimics), and a large (approximately 400 nucleotide) group I ribozyme RNA is detected. The ability to screen large RNAs alleviates many complications associated with binding experiments that use isolated truncated regions from larger RNAs. These studies lay the foundation for rapid identification of small organic ligands from combinatorial libraries that exhibit strong and selective RNA binding while displaying decreased affinity to toxicity-causing proteins. PMID:15224340

  3. XBP1 mitigates aminoglycoside-induced endoplasmic reticulum stress and neuronal cell death.

    Science.gov (United States)

    Oishi, N; Duscha, S; Boukari, H; Meyer, M; Xie, J; Wei, G; Schrepfer, T; Roschitzki, B; Boettger, E C; Schacht, J

    2015-01-01

    Here we study links between aminoglycoside-induced mistranslation, protein misfolding and neuropathy. We demonstrate that aminoglycosides induce misreading in mammalian cells and assess endoplasmic reticulum (ER) stress and unfolded protein response (UPR) pathways. Genome-wide transcriptome and proteome analyses revealed upregulation of genes related to protein folding and degradation. Quantitative PCR confirmed induction of UPR markers including C/EBP homologous protein, glucose-regulated protein 94, binding immunoglobulin protein and X-box binding protein-1 (XBP1) mRNA splicing, which is crucial for UPR activation. We studied the effect of a compromised UPR on aminoglycoside ototoxicity in haploinsufficient XBP1 (XBP1(+/-)) mice. Intra-tympanic aminoglycoside treatment caused high-frequency hearing loss in XBP1(+/-) mice but not in wild-type littermates. Densities of spiral ganglion cells and synaptic ribbons were decreased in gentamicin-treated XBP1(+/-) mice, while sensory cells were preserved. Co-injection of the chemical chaperone tauroursodeoxycholic acid attenuated hearing loss. These results suggest that aminoglycoside-induced ER stress and cell death in spiral ganglion neurons is mitigated by XBP1, masking aminoglycoside neurotoxicity at the organismal level. PMID:25973683

  4. Kinetic and Structural Analysis of Bisubstrate Inhibition of the Salmonella enterica Aminoglycoside 6′-N-Acetyltransferase†,‡

    OpenAIRE

    Magalhães, Maria L. B.; Vetting, Matthew W.; Gao, Feng; Freiburger, Lee; Auclair, Karine; Blanchard, John S.

    2007-01-01

    Aminoglycosides are antibacterial compounds that act by binding to the A site of the small 30S bacterial ribosomal subunit and inhibiting protein translation. Clinical resistance to aminoglycosides is generally the result of the expression of enzymes that covalently modify the antibiotic, including phosphorylation, adenylylation, and acetylation. Bisubstrate analogs for the aminoglycoside N-acetyl-transferases are nanomolar inhibitors of Enterococcus faecium AAC(6′)-Ii. However, in the case o...

  5. Serum Aminoglycoside Assay by Enzyme-Mediated Immunoassay (EMIT): Correlation with Radioimmunoassay, Fluoroimmunoassay, and Acetyltransferase and Microbiological Assays

    OpenAIRE

    White, L O; Scammell, L. M.; Reeves, D S

    1981-01-01

    Enzyme-mediated immunoassay (EMIT) serum aminoglycoside assay results were accurate and precise and correlated well with radioimmunoassay, fluoroimmunoassay, and acetyltransferase and microbiological assay determinations.

  6. Clinical Pharmacokinetics of Penicillins, Cephalosporins and Aminoglycosides in the Neonate: A Review

    Directory of Open Access Journals (Sweden)

    Gian Maria Pacifici

    2010-08-01

    Full Text Available Bacterial infections are common in the neonates and are a major cause of morbidity and mortality. Sixty percent of preterm infants admitted to neonatal intensive care units received at least one antibiotic during the first week of life. Penicillins, aminoglycosides and cephalosporins comprised 53, 43 and 16%, respectively. Kinetic parameters such as the half-life (t1/2, clearance (Cl, and volume of distribution (Vd change with development, so the kinetics of penicillins, cephalosporins and aminoglycosides need to be studied in order to optimise therapy with these drugs. The aim of this study is to review the pharmacokinetics of penicillins, cephalosporins and aminoglycosides in the neonate in a single article in order to provide a critical analysis of the literature and thus provide a useful tool in the hands of physicians. The bibliographic search was performed electronically using PubMed, as the search engine, until February 2nd, 2010. Medline search terms were as follows: pharmacokinetics AND (penicillins OR cephalosporins OR aminoglycosides AND infant, newborn, limiting to humans. Penicillins, cephalosporins and aminoglycosides are fairly water soluble and are mainly eliminated by the kidneys. The maturation of the kidneys governs the pharmacokinetics of penicillins, cephalosporins and aminoglycosides in the neonate. The renal excretory function is reduced in preterms compared to term infants and Cl of these drugs is reduced in premature infants. Gestational and postnatal ages are important factors in the maturation of the neonate and, as these ages proceed, Cl of penicillins, cephalosporins and aminoglycosides increases. Cl and t1/2 are influenced by development and this must be taken into consideration when planning a dosage regimen with these drugs. More pharmacokinetic studies are required to ensure that the dose recommended for the treatment of sepsis in the neonate is evidence based.

  7. A surprising dipolar cycloaddition provides ready access to aminoglycosides.

    Science.gov (United States)

    Dahl, Russell S; Finney, Nathaniel S

    2004-07-14

    This contribution describes the results of a new research effort in our laboratory aimed at the synthesis of novel aminoglycosides and amino-C-glycosides. Despite the importance of such compounds, and the previous development of some methodological solutions, this remains an important area of research. Notable features of our approach, which is distinct from and complementary to previous efforts, are the following: (1) Reliance on a surprising and unprecedented formation of glycal triazolines via an inverse electron demand dipolar cycloaddition of glucal. We believe this desirable transformation has not previously been discovered because of the unusual selection of substrates and solvent required. (2) Very mild reaction conditions. An initial thermal cycloaddition is carried out in an inert solvent, the triazoline generated is photochemically converted to a reactive aziridine, and the crude aziridine undergoes ring opening at room temperature in the presence of a nucleophile and a mild Lewis acid catalyst. (3) Formation of products lacking an N-acyl group, allowing ready synthesis of novel glucosamine derivatives. PMID:15237974

  8. Environmental and genetic factors affecting mutability to aminoglycoside antibiotics among Escherichia coli K12 strains

    Directory of Open Access Journals (Sweden)

    Monteiro A.C.M.

    2003-01-01

    Full Text Available Environmental and genetic factors affecting the in vitro spontaneous mutation frequencies to aminoglycoside resistance in Escherichia coli K12 were investigated. Spontaneous mutation frequencies to kanamycin resistance were at least 100 fold higher on modified Luria agar (L2 plates, when compared to results obtained in experiments carried out with Nutrient agar (NA plates. In contrast to rifampincin, the increased mutability to kanamycin resistance could not be attributed to a mutator phenotype expressed by DNA repair defective strains. Kanamycin mutant selection windows and mutant preventive concentrations on L2 plates were at least fourfold higher than on NA plates, further demonstrating the role of growth medium composition on the mutability to aminoglycosides. Mutability to kanamycin resistance was increased following addition of sorbitol, suggesting that osmolarity is involved on the spontaneous mutability of E. coli K12 strains to aminoglycosides. The spontaneous mutation rates to kanamycin resistance on both L2 and NA plates were strictly associated with the selective antibiotic concentrations. Moreover, mutants selected at different antibiotic concentrations expressed heterogeneous resistance levels to kanamycin and most of them expressing multiple resistance to all tested aminoglycoside antibiotics (gentamicin, neomycin, amykacin and tobramycin. These results will contribute to a better understanding of the complex nature of aminoglycoside resistance and the emergence of spontaneous resistant mutants among E. coli K12 strains.

  9. Triclosan-Induced Aminoglycoside-Tolerant Listeria monocytogenes Isolates Can Appear as Small-Colony Variants

    DEFF Research Database (Denmark)

    Kastbjerg, Vicky Gaedt; Hein-Kristensen, Line; Gram, Lone

    2014-01-01

    Exposure of the human food-borne pathogen Listeria monocytogenes to sublethal concentrations of triclosan can cause resistance to several aminoglycosides. Aminoglycoside-resistant isolates exhibit two colony morphologies: normal-size and pinpoint colonies. The purposes of the present study were to...... heme gene, and addition of heme caused the pinpoint isolates to revert to normal colony size. Triclosan-induced gentamicin-resistant isolates had mutations in several different genes, and it cannot be directly concluded how the different mutations caused gentamicin resistance. However, since many of...... the mutations affected proteins involved in respiration, it seems likely that the mutations affected the active transport of the antibiotic and thereby caused resistance by decreasing the amount of aminoglycoside that enters the bacterial cell. Our study emphasizes that triclosan likely has more...

  10. Emergence of aminoglycoside resistance genes aadA and aadE in the genus Campylobacter.

    OpenAIRE

    Pinto-Alphandary, H; Mabilat, C; Courvalin, P

    1990-01-01

    Resistance to streptomycin or spectinomycin or both in five Campylobacter coli strains, two Campylobacter jejuni strains, and a Campylobacter-like strain was studied by enzymatic assays and dot blot hybridization. Resistance was due to 6- or 3",9-aminoglycoside adenylyltransferases and to new types of phospho- and adenylyltransferases.

  11. Single biosensor immunoassay for the detection of five aminoglycosides in reconstituted skimmed milk

    NARCIS (Netherlands)

    Haasnoot, W.; Cazemier, G.; Koets, M.; Amerongen, van A.

    2003-01-01

    The application of an optical biosensor (Biacore 3000), with four flow channels (Fcs), in combination with a mixture of four specific antibodies resulted in a competitive inhibition biosensor immunoassay (BIA) for the simultaneous detection of the five relevant aminoglycosides in reconstituted skimm

  12. 21 CFR 573.130 - Aminoglycoside 3′-phospho- transferase II.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aminoglycoside 3â²-phospho- transferase II. 573.130 Section 573.130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... genetically modified cotton, oilseed rape, and tomatoes in accordance with the following prescribed...

  13. Natural bizbenzoquinoline derivatives protect zebrafish lateral line sensory hair cells from aminoglycoside toxicity

    Directory of Open Access Journals (Sweden)

    Matthew eKruger

    2016-03-01

    Full Text Available Moderate to severe hearing loss affects 360 million people worldwide and most often results from damage to sensory hair cells. Hair cell damage can result from aging, genetic mutations, excess noise exposure, and certain medications including aminoglycoside antibiotics. Aminoglycosides are effective at treating infections associated with cystic fibrosis and other life-threatening conditions such as sepsis, but cause hearing loss in 20-30% of patients. It is therefore imperative to develop new therapies to combat hearing loss and allow safe use of these potent antibiotics. We approach this drug discovery question using the larval zebrafish lateral line because zebrafish hair cells are structurally and functionally similar to mammalian inner ear hair cells and respond similarly to toxins. We screened a library of 502 natural compounds in order to identify novel hair cell protectants. Our screen identified four bisbenzylisoquinoline derivatives: berbamine, E6 berbamine, hernandezine, and isotetrandrine, each of which robustly protected hair cells from aminoglycoside-induced damage. Using fluorescence microscopy and electrophysiology, we demonstrated that the natural compounds confer protection by reducing antibiotic uptake into hair cells and showed that hair cells remain functional during and after incubation in E6 berbamine. We also determined that these natural compounds do not reduce antibiotic efficacy. Together, these natural compounds represent a novel source of possible otoprotective drugs that may offer therapeutic options for patients receiving aminoglycoside treatment.

  14. Structural Analysis of a Putative Aminoglycoside N-Acetyltransferase from Bacillus anthracis

    Energy Technology Data Exchange (ETDEWEB)

    Klimecka, Maria M.; Chruszcz, Maksymilian; Font, Jose; Skarina, Tatiana; Shumilin, Igor; Onopryienko, Olena; Porebski, Przemyslaw J.; Cymborowski, Marcin; Zimmerman, Matthew D.; Hasseman, Jeremy; Glomski, Ian J.; Lebioda, Lukasz; Savchenko, Alexei; Edwards, Aled; Minor, Wladek (SC); (Toronto); (UV)

    2012-02-15

    For the last decade, worldwide efforts for the treatment of anthrax infection have focused on developing effective vaccines. Patients that are already infected are still treated traditionally using different types of standard antimicrobial agents. The most popular are antibiotics such as tetracyclines and fluoroquinolones. While aminoglycosides appear to be less effective antimicrobial agents than other antibiotics, synthetic aminoglycosides have been shown to act as potent inhibitors of anthrax lethal factor and may have potential application as antitoxins. Here, we present a structural analysis of the BA2930 protein, a putative aminoglycoside acetyltransferase, which may be a component of the bacterium's aminoglycoside resistance mechanism. The determined structures revealed details of a fold characteristic only for one other protein structure in the Protein Data Bank, namely, YokD from Bacillus subtilis. Both BA2930 and YokD are members of the Antibiotic-NAT superfamily (PF02522). Sequential and structural analyses showed that residues conserved throughout the Antibiotic-NAT superfamily are responsible for the binding of the cofactor acetyl coenzyme A. The interaction of BA2930 with cofactors was characterized by both crystallographic and binding studies.

  15. 21 CFR 173.170 - Aminoglycoside 3′-phospho-trans-ferase II.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SECONDARY DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.170 Aminoglycoside 3′-phospho-trans... development of genetically modified cotton, oilseed rape, and tomatoes in accordance with the...

  16. Natural Bizbenzoquinoline Derivatives Protect Zebrafish Lateral Line Sensory Hair Cells from Aminoglycoside Toxicity.

    Science.gov (United States)

    Kruger, Matthew; Boney, Robert; Ordoobadi, Alexander J; Sommers, Thomas F; Trapani, Josef G; Coffin, Allison B

    2016-01-01

    Moderate to severe hearing loss affects 360 million people worldwide and most often results from damage to sensory hair cells. Hair cell damage can result from aging, genetic mutations, excess noise exposure, and certain medications including aminoglycoside antibiotics. Aminoglycosides are effective at treating infections associated with cystic fibrosis and other life-threatening conditions such as sepsis, but cause hearing loss in 20-30% of patients. It is therefore imperative to develop new therapies to combat hearing loss and allow safe use of these potent antibiotics. We approach this drug discovery question using the larval zebrafish lateral line because zebrafish hair cells are structurally and functionally similar to mammalian inner ear hair cells and respond similarly to toxins. We screened a library of 502 natural compounds in order to identify novel hair cell protectants. Our screen identified four bisbenzylisoquinoline derivatives: berbamine, E6 berbamine, hernandezine, and isotetrandrine, each of which robustly protected hair cells from aminoglycoside-induced damage. Using fluorescence microscopy and electrophysiology, we demonstrated that the natural compounds confer protection by reducing antibiotic uptake into hair cells and showed that hair cells remain functional during and after incubation in E6 berbamine. We also determined that these natural compounds do not reduce antibiotic efficacy. Together, these natural compounds represent a novel source of possible otoprotective drugs that may offer therapeutic options for patients receiving aminoglycoside treatment. PMID:27065807

  17. Evaluation of Aminoglycoside and Non-Aminoglycoside Compounds for Stop-Codon Readthrough Therapy in Four Lysosomal Storage Diseases.

    Directory of Open Access Journals (Sweden)

    Marta Gómez-Grau

    Full Text Available Nonsense mutations are quite prevalent in inherited diseases. Readthrough drugs could provide a therapeutic option for any disease caused by this type of mutation. Geneticin (G418 and gentamicin were among the first to be described. Novel compounds have been generated, but only a few have shown improved results. PTC124 is the only compound to have reached clinical trials. Here we first investigated the readthrough effects of gentamicin on fibroblasts from one patient with Sanfilippo B, one with Sanfilippo C, and one with Maroteaux-Lamy. We found that ARSB activity (Maroteaux-Lamy case resulted in an increase of 2-3 folds and that the amount of this enzyme within the lysosomes was also increased, after treatment. Since the other two cases (Sanfilippo B and Sanfilippo C did not respond to gentamicin, the treatments were extended with the use of geneticin and five non-aminoglycoside (PTC124, RTC13, RTC14, BZ6 and BZ16 readthrough compounds (RTCs. No recovery was observed at the enzyme activity level. However, mRNA recovery was observed in both cases, nearly a two-fold increase for Sanfilippo B fibroblasts with G418 and around 1.5 fold increase for Sanfilippo C cells with RTC14 and PTC124. Afterwards, some of the products were assessed through in vitro analyses for seven mutations in genes responsible for those diseases and, also, for Niemann-Pick A/B. Using the coupled transcription/translation system (TNT, the best results were obtained for SMPD1 mutations with G418, reaching a 35% recovery at 0.25 μg/ml, for the p.W168X mutation. The use of COS cells transfected with mutant cDNAs gave positive results for most of the mutations with some of the drugs, although to a different extent. The higher enzyme activity recovery, of around two-fold increase, was found for gentamicin on the ARSB p.W146X mutation. Our results are promising and consistent with those of other groups. Further studies of novel compounds are necessary to find those with more

  18. Rapid analysis of aminoglycoside antibiotics in bovine tissues using disposable pipette extraction and ultrahigh performance liquid chromatography - tandem mass spectrometry

    Science.gov (United States)

    A high-throughput qualitative screening and identification method for 9 aminoglycosides of regulatory interest has been developed, validated, and implemented for bovine kidney, liver, and muscle tissues. The method involves extraction at previously validated conditions, cleanup using disposable pip...

  19. Defining RNA motif–aminoglycoside interactions via two-dimensional combinatorial screening and structure–activity relationships through sequencing

    OpenAIRE

    Velagapudi, Sai Pradeep; Disney, Matthew D.

    2013-01-01

    RNA is an extremely important target for the development of chemical probes of function or small molecule therapeutics. Aminoglycosides are the most well studied class of small molecules to target RNA. However, the RNA motifs outside of the bacterial rRNA A-site that are likely to be bound by these compounds in biological systems is largely unknown. If such information were known, it could allow for aminoglycosides to be exploited to target other RNAs and, in addition, could provide invaluabl...

  20. Structural and Molecular Basis for Resistance to Aminoglycoside Antibiotics by the Adenylyltransferase ANT(2″)-Ia

    OpenAIRE

    Cox, Georgina; Peter J. Stogios; Savchenko, Alexei; Wright, Gerard D.

    2015-01-01

    ABSTRACT   The aminoglycosides are highly effective broad-spectrum antimicrobial agents. However, their efficacy is diminished due to enzyme-mediated covalent modification, which reduces affinity of the drug for the target ribosome. One of the most prevalent aminoglycoside resistance enzymes in Gram-negative pathogens is the adenylyltransferase ANT(2″)-Ia, which confers resistance to gentamicin, tobramycin, and kanamycin. Despite the importance of this enzyme in drug resistance, its structure...

  1. Assessment on the adverse effects of Aminoglycosides and Flouroquinolone on sperm parameters and male reproductive tissue: A systematic review

    OpenAIRE

    Arash Khaki

    2015-01-01

    Background: Antibiotic therapies used in treatment of many diseases have adverse effects on fertility. This review analyzes previous comparative studies that surveyed the effects of two common groups of antibiotics on male fertility. Objective: To evaluate histo-pathological effects of fluoroquinolones and aminoglycosides on sperm parameters and male reproductive tissue. Materials and Methods: Articles about the effects of aminoglycosides and fluoroquinolones on male infertility, sperm parame...

  2. Directed Evolution of Aminoglycoside Phosphotransferase (3′) Type IIIa Variants That Inactivate Amikacin but Impose Significant Fitness Costs

    OpenAIRE

    Kramer, Joseph R.; Matsumura, Ichiro

    2013-01-01

    The rules that govern adaptive protein evolution remain incompletely understood. Aminoglycoside aminotransferase (3′) type IIIa (hereafter abbreviated APH(3′)-IIIa) is a good model enzyme because it inactivates kanamycin efficiently; it recognizes other aminoglycoside antibiotics, including amikacin, but not nearly as well. Here we direct the evolution of APH(3′)-IIIa variants with increased activity against amikacin. After four rounds of random mutation and selection in Escherichia coli, the...

  3. Aminoglycoside Efflux in Pseudomonas aeruginosa: Involvement of Novel Outer Membrane Proteins

    OpenAIRE

    Jo, James T. H.; Brinkman, Fiona S.L.; Hancock, Robert E W

    2003-01-01

    The expression of tripartite multidrug efflux pumps such as MexA-MexB-OprM in Pseudomonas aeruginosa contributes to intrinsic resistance to a wide variety of antimicrobials, including β-lactams, chloramphenicol, macrolides, quinolones, and tetracycline. The MexX-MexY linker-pump combination has been shown to be involved in intrinsic resistance to aminoglycosides, but the identity of the cognate outer membrane channel component remains under debate. Fourteen uncharacterized OprM homologs ident...

  4. Molecular Epidemiology of Aminoglycosides Resistance in Acinetobacter Spp. with Emergence of Multidrug-Resistant Strains

    Directory of Open Access Journals (Sweden)

    MH Nazem Shirazi

    2010-06-01

    Full Text Available Background: Acinetobacter spp. is characterized as an important nosocomial pathogen and increasing antimicrobial resistance. Our aim was to evaluate antimicrobial susceptibility and aminoglycosides resistance genes of Acinetobacter spp. isolated from hospitalized patients.Methods: Sixty isolates were identified as Acinetobacter species. The isolates were tested for antibiotic resistance by disc diffusion method for 12 antimicrobials. The presence of aphA6, aacC1 aadA1, and aadB genes were detected using PCR.Results: From the isolated Acinetobacter spp. the highest resistance rate showed against amikacin, tobramycin, and ceftazidim, respectively; while isolated bacteria were more sensitive to ampicillic/subactam. More than 66% of the isolates were resistant to at least three classes of antibiotics, and 27.5% of MDR strains were resistant to all seven tested classes of antimicrobials. The higher MDR rate presented in bacteria isolated from the ICU and blood samples. More than 60% of the MDR bacteria were resistance to amikacin, ceftazidim, ciprofloxacin, piperacillin/tazobactam, doxycycline, tobramycin and levofloxacin. Also, more than 60% of the isolates contained phosphotransferase aphA6, and acetyltransferase genes aacC1, but adenylyltransferase genes aadA1 (41.7%, and aadB (3.3% were less prominent. 21.7% of the strains contain three aminoglycoside resistance genes (aphA6, aacC1 and aadA1.Conclusion: The rising trend of resistance to aminoglycosides poses an alarming threat to treatment of such infections. The findings showed that clinical isolates of Acinetobacter spp. in our hospital carrying various kinds of aminoglycoside resistance genes.

  5. Synthesis of 4′-aminopantetheine and derivatives to probe aminoglycoside N-6′-acetyltransferase

    OpenAIRE

    Yan, Xuxu; Akinnusi, T. Olukayode; Larsen, Aaron T.; Auclair, Karine

    2011-01-01

    A convenient synthesis of 4′-aminopantetheine from commercial D-pantethine is reported. The amino group was introduced by reductive amination in order to avoid substitution at a sterically congested position. Derivatives of 4′-aminopantetheine were also prepared to evaluate the effect of O-to-N substitution on inhibitors of the resistance-causing enzyme aminoglycoside N-6′-acetyltransferase. The biological results combined with docking studies indicate that in spite of its reported unusual fl...

  6. Evaluation of Antibacterial Activity of Aminoglycosides and Modulating the Essential Oil of Cymbopogon citratus (DC.) Stapf

    OpenAIRE

    Tintino, Saulo R.; Lucena, Bruno F. F.; Fernando G. Figueredo; Cícera Datiane de M. OLIVEIRA; José J. DOS S. AGUIAR; Edmilson DO N. CARDOSO; Pedro E. A. DE AQUINO; Jacqueline C. ANDRADE; Coutinho, Henrique D. M.; Ednardo F. F. MATIAS

    2014-01-01

     Several works demonstrated the importance of the study of natural products as an alternative source for new antimicrobial drugs or for modulators for these ones. In this point, the aim of this was to investigate the antibacterial activity and the possible interactions between the essential oil of Cymbopogon citratus alone and in association with aminoglycosides against standard and clinically isolated strains of multidrug-resistant bacteria such as S. aureus, E. coli and P. aeruginosa by mic...

  7. Cymbopogon citratus protects against the renal injury induced by toxic doses of aminoglycosides in rabbits

    OpenAIRE

    Ullah, N.; Khan, M. A.; Khan, T.; W Ahmad

    2013-01-01

    Renal injury is the most common side-effect of aminoglycosides. These antimicrobial drugs are particularly effective against Gram-negative microorganisms. The present study was conducted to investigate the renal protective activity of Cymbopogon citratus in gentamicin-induced nephrotoxicity. Male rabbits were divided into four groups (n=6) including group 1 (0.9% saline treated), group 2 (80 mg/kg/day gentamicin-treated), group 3 (200 mg/kg/day Cymbopogon citratus treated) and group 4 (80 mg/...

  8. Intrasaccular injection of aminoglycosides: a novel method for temporary damaging fish inner ear hair cells

    OpenAIRE

    Faucher, Karine; Aas-Hansen, Øyvind; Damsgard, Borge; Stenklev, Niels-Christian

    2008-01-01

    Fish models are increasingly being used for hearing research investigations. Aminoglycoside antibiotics that are used for damaging the inner ear hair cells can have systemic side effects leading to death of study animals. This study aimed to compare two methods: i) systemic (intravenous) and ii) local (intrasaccular) gentamicin administration for induction of inner ear hair cell damage in the Atlantic cod, Gadus morhua (L.). Hair cell damage was assessed using scanning electron microscopy; ha...

  9. Effects of salicylates and aminoglycosides on spontaneous otoacoustic emissions in the Tokay gecko

    OpenAIRE

    Stewart, Charles E; Hudspeth, A. James

    2000-01-01

    The high sensitivity and sharp frequency discrimination of hearing depend on mechanical amplification in the cochlea. To explore the basis of this active process, we examined the pharmacological sensitivity of spontaneous otoacoustic emissions (SOAEs) in a lizard, the Tokay gecko. In a quiet environment, each ear produced a complex but stable pattern of emissions. These SOAEs were reversibly modulated by drugs that affect mammalian otoacoustic emissions, the salicylates and the aminoglycoside...

  10. In vitro activities of quinolones against enterococci resistant to penicillin-aminoglycoside synergy.

    OpenAIRE

    Sahm, D F; Koburov, G T

    1989-01-01

    The MICs and MBCs of CI-934, ciprofloxacin, difloxacin (A-56619), A-56620, norfloxacin, enoxacin, amifloxacin, and coumermycin were determined for 43 clinical isolates of Enterococcus faecalis known to be resistant to penicillin-aminoglycoside synergy. Results were compared with those obtained for 37 synergy-susceptible E. faecalis and 22 Enterococcus faecium strains. Although no substantial differences in quinolone activities were observed between synergy-resistant and -susceptible E. faecal...

  11. Rescue of non-sense mutated p53 tumor suppressor gene by aminoglycosides

    OpenAIRE

    Floquet, Célia; Deforges, Jules; Rousset, Jean-Pierre; Bidou, Laure

    2010-01-01

    Mutation-based treatments are a new development in genetic medicine, in which the nature of the mutation dictates the therapeutic strategy. Interest has recently focused on diseases caused by premature termination codons (PTCs). Drugs inducing the readthrough of these PTCs restore the production of a full-length protein. In this study, we explored the possibility of using aminoglycoside antibiotics to induce the production of a full-length functional p53 protein from a gene carrying a PTC. We...

  12. Preparation and characterization of dehydration-rehydration vesicles loaded with aminoglycoside and macrolide antibiotics.

    Science.gov (United States)

    Mugabe, Clement; Azghani, Ali O; Omri, Abdelwahab

    2006-01-13

    Enhanced activity of liposomes-encapsulated antibiotics against clinical isolates of Pseudomonas aeruginosa has been documented with liposomes of low encapsulation efficiency. We sought to construct liposomes with high yield entrapment of aminoglycoside and macrolide antibiotics as well as favorable stability in storage and physiological conditions. Liposome-entrapped aminoglycosides (amikacin, gentamicin, tobramycin) and a macrolide (erythromycin) were prepared by a modified dehydration-rehydration vesicles (DRVs) method, and their particle size and entrapment efficiency were determined. We studied in vitro stability of these vesicles over a 48 h period at 4 and 37 degrees C in phosphate-buffered saline (PBS) and in plasma at 37 degrees C. The mean particle size of DRVs loaded with antibiotics varied from 163.37+/-38.44 to 259.83+/-11.80 nm with no significant difference in regard with the type of the antibiotics encapsulated. Encapsulation efficiency of DRVs loaded with amikacin, gentamicin, tobramycin, and erythromycin were 29.27+/-1.17, 33+/-0.76, 22.33+/-1.48 and 32.06+/-0.82% of initial amount of the drug, respectively. These vesicles were stable regardless of the experimental temperature. Indeed, the liposomes retained more than 75% of the initially encapsulated drugs for the study period of 48 h. DRVs incubated in plasma however, released more antibiotics than those incubated in PBS. In conclusion, using this modified DRV method, we obtained small sized vesicles with high yield entrapment for aminoglycoside and macrolide antibiotics. The technique may be utilized to overcome the low encapsulation efficiency associated with aminoglycoside and macrolide antibiotics. PMID:16289986

  13. Sodium-Glucose Transporter-2 (SGLT2; SLC5A2) Enhances Cellular Uptake of Aminoglycosides

    OpenAIRE

    Meiyan Jiang; Qi Wang; Takatoshi Karasawa; Ja-Won Koo; Hongzhe Li; Steyger, Peter S.

    2014-01-01

    Aminoglycoside antibiotics, like gentamicin, continue to be clinically essential worldwide to treat life-threatening bacterial infections. Yet, the ototoxic and nephrotoxic side-effects of these drugs remain serious complications. A major site of gentamicin uptake and toxicity resides within kidney proximal tubules that also heavily express electrogenic sodium-glucose transporter-2 (SGLT2; SLC5A2) in vivo. We hypothesized that SGLT2 traffics gentamicin, and promotes cellular toxicity. We conf...

  14. LC-MS/MS-Methoden zur Rückstandsanalyse von Penicillinen, Cephalosporinen und Aminoglycosid-Antibiotika

    OpenAIRE

    Becker, Matthias

    2014-01-01

    In today’s livestock farming and milk production, therapeutic, metaphylactic and prophylactic use of ß-lactams (penicillins, cephalosporins) and aminoglycosides is inevitable. However, improper use of these antibiotics may lead to residues in milk and edible tissues and can cause human health hazards as well as technological problems in dairy industry. In general, antibiotics are unwanted components in food, and it has to be ensured that the consumer is not exposed to antibioti...

  15. Study of Klebsiella pneumoniae producing extended-spectrum β-lactamases against aminoglycosides

    Institute of Scientific and Technical Information of China (English)

    WEI FENG SHI; SU JIAN WANG; JIAN PING QIN

    2007-01-01

    Klebsiella pneumoniae ( K. pneumoniae) is one of the main gram-negative bacilli in clinical practice. Nosocomial infections caused by K. pneumoniae producing extended-spectrum β-lactamases (ESBLs) are very difficult to treat. This paper investigated the resistant characteristics of K. pneumoniae producing ESBLs and their aminoglycoside-modifying enzyme gene expressions including Nacetyltransferases and O-adenyhransferases. Bacteria identification and ESBLs confirmatory tests were performed by Phoenix TM-100 system. And minimum inhibitory concentrations (MICs) of gentamicin,amikacin, kanamycin, tobramycin, netilmicin and neomycin in 53 K. pneumoniae isolates were detected by agar dilution. In addition, six aminoglycoside-modifying enzyme genes were amplified by polymerase chain reaction (PCR) and verified by DNA sequencer. It was found that imipenem and meropenem against 120 K. pneumoniae isolates produced powerful antimicrobial activities. The resistant rates of gentamicin and amikacin were 55.0% and 46.7%, respectively. Except neomycin,MIC50 and MIC90 of gentamicin, amikacin, kanamycin, tobramycin and netilmicin in 53 K. pneumoniae were all > 128 μg/ml, and the resistant rates were 83.0%, 52.3%, 75.5%, 81. 1% and 69.8%, respectively. However, neomycin was only 39.6%. In addition, five modifying enzyme genes, including aac(3)- Ⅰ , aac(3)-Ⅱ, aac(6′) - Ⅰ b, ant(3″) - Ⅰ, ant(2″) - Ⅰ genes, were found in 53 isoahes except aac (6′)-Ⅱ, and their positive rates were 11.3%, 67.9%, 47.2%,1.9 % and 39.6 %, respectively. It was also confirmed by nucleotide sequence analysis that the above resistant genes shared nearly 100% identities with GenBank published genes. The results obtained in the present study indicated that K. pneumoniae producing ESBLs strains are rapidly spreading in our hospital, and their resistance to aminoglycosides may be associated with aminoglycoside-modifying enzyme gene expressions.

  16. Synergistic Effect of Oleanolic Acid on Aminoglycoside Antibiotics against Acinetobacter baumannii.

    Directory of Open Access Journals (Sweden)

    Bora Shin

    Full Text Available Difficulties involved in treating drug-resistant pathogens have created a need for new therapies. In this study, we investigated the possibility of using oleanolic acid (OA, a natural pentacyclic triterpenoid, as a natural adjuvant for antibiotics against Acinetobacter baumannii. High concentrations of OA can kill cells, partly because it generates reactive oxygen species. Measurement of the fractional inhibitory concentration (FIC for OA and time-kill experiments demonstrated that it only synergizes with aminoglycoside antibiotics (e.g., gentamicin, kanamycin. Other classes of antibiotics (e.g., ampicillin, rifampicin, norfloxacin, chloramphenicol, and tetracycline have no interactions with OA. Microarray and quantitative reverse transcription-PCR analysis indicated that genes involved in ATP synthesis and cell membrane permeability, the gene encoding glycosyltransferase, peptidoglycan-related genes, phage-related genes, and DNA repair genes were upregulated under OA. OA highly induces the expression of adk, which encodes an adenylate kinase, and des6, which encodes a linoleoyl-CoA desaturase, and deletion of these genes increased FICs; these observations indicate that adk and des6 are involved in the synergism of OA with aminoglycosides. Data obtained using 8-anilino-1-naphthalenesulfonic acid, fluorescence-conjugated gentamicin, and membrane fatty acid analysis indicates that adk and des6 are involved in changes in membrane permeability. Proton-motive force and ATP synthesis tests show that those genes are also involved in energy metabolism. Taken together, our data show that OA boosts aminoglycoside uptake by changing membrane permeability and energy metabolism in A. baumannii.

  17. LOWER DOSE OF AMINOGLYCOSIDE OTOTOXIC EXPOSURE CAUSES PRESYNAPTIC ALTERATIONS ASSOICATED WITH HEARING LOSS

    Institute of Scientific and Technical Information of China (English)

    LIU Ke; WANG Xiaoyu; LI Sijun; TANG Siquan; XU Yice; WANG Xuefeng; SUN Jianhe; YANG Weiyan; YANG Shiming

    2014-01-01

    Objective To study presynaptic alternations of cochlear ribbons arising from aminoglycoside ototoxic stimuli in C57BL/6J mice. Methods Animals were injected with low dose gentamicin (100 mg/kg/day) for 14 days, From the 14th to 28th days, the mice were maintained free of gentamicin treatment. Immunohisto-chemistry labeling was employed to trace RIBEYE, a major presynaptic componment of ribbon synapses. RIBEYE/CtBP2 expression levels were assessed and compared with hearing threshold shifts. Auditory func-tion was assessed by auditory brainstem responses. The stereocilia of outer hair cells (OHCs) and IHCs was examined by scanning electron microscopy (SEM). Results Hearing thresholds were elevated with peak hearing loss observed on the 7th day after gentamicin exposure, followed by improvement after the 7th day. RIBEYE/CtBP2 expression directly correlated with observed hearing threshold shifts. Strikingly, we did not see any obvious changes in stereocilia in both OHCs and IHCs until the 28th day. Mild changes in stereocil-ia were only observed in OHCs on the 28th day. Conclusions These findings indicate that presynapse co-chlear ribbons, rather than stereocilia, may be sensitive to aminoglycoside ototoxic exposure in mice cochle-ae. A pattern of RIBEYE/CtBP2 expression changes seems to parallel hearing threshold shifts and suggests presynaptic response properties to lower dosage of aminoglycoside ototoxic stimuli.

  18. Dissecting the cosubstrate structure requirements of the Staphylococcus aureus aminoglycoside resistance enzyme ANT(4').

    Science.gov (United States)

    Porter, Vanessa R; Green, Keith D; Zolova, Olga E; Houghton, Jacob L; Garneau-Tsodikova, Sylvie

    2010-12-01

    Aminoglycosides are important antibiotics used against a wide range of pathogens. As a mechanism of defense, bacteria have evolved enzymes able to inactivate these drugs by regio-selectively adding a variety of functionalities (acetyl, phospho, and nucelotidyl groups) to their scaffolds. The aminoglycoside nucleotidyltransferase ANT(4') is one of the most prevalent and unique modifying-enzymes. Here, by TLC, HRMS, and colorimetric assays, we demonstrate that the resistance enzyme ANT(4') from Staphylococcus aureus is highly substrate and cosubstrate promiscuous. We show that deoxy-ribonucleotide triphosphates (dNTPs) are better cosubstrates than NTPs. We demonstrate that the position of the triphosphate group (5' and not 3') on the ribose/deoxyribose ring is important for recognition by ANT(4'), and that NTPs with larger substituents at the 3'-position of the ribose ring are not cosubstrates for ANT(4'). We confirm that for all aminoglycosides tested, the respective nucleotidylated products are completely inactive. These results provide valuable insights into the development of strategies to combat the ever-growing bacterial resistance problem. PMID:21040710

  19. [Is it possible to reduce the incidence of aminoglycoside-induced nephrotoxicity?].

    Science.gov (United States)

    Fillastre, J P

    1999-01-01

    The incidence of nephrotoxicity due to aminoglycosides should be sharply reduced. The indications for prescribing these antibiotics should be limited to infectious disorders induced by aerobic Gram-negative bacteria and by some Gram-positive bacteria requiring treatment in specialized hospital units using an association of aminoglycosides and another antibiotic. Daily doses should not exceed those indicated by the manufacturer, and the length of treatment should be as short as possible, with a relay to other antibiotics that are not or are less nephrotoxic. The possibilities for reducing the incidence of nephrotoxicity are few. It is not possible to prevent the antibiotic from entering the renal tubular cell or from producing deleterious effects therein. However, by using short-term intravenous infusion as the administration route, prolonged contact between the antibiotic and its receptors on the brush borders of the proximal tubular cells can be avoided, particularly since the process of cellular absorption is saturable. Essentially, doses should be adapted according to the age and the glomerular filtration of the patient, since renal function usually decreases with age. Volemic and hydroelectrolytic disorders favour nephrotoxicity and should be corrected. Associations with other nephrotoxic drugs should either be avoided or used with increased caution. The same is true in special situations such as endotoxaemia, severe renal parenchymatous infections and cholestasis. In any case, given the well-known insidious onset of nephropathy, aminoglycoside treatment always requires laboratory follow-up consisting of repeated testing of creatinemia during the two weeks of treatment. PMID:10465001

  20. Heparin interferes with the radioenzymatic and homogeneous enzyme immunoassays for aminoglycosides

    International Nuclear Information System (INIS)

    Heparin interferes with measurement of aminoglycosides in serum by biological, radioenzymatic, and homogeneous enzyme immunoassay techniques, but not with radioimmunoassay. At concentrations greater than or equal to 105 and greater than or equal to 3 X 106 USP units/L, respectively, it interferes with the radioenzymatic assay by inhibiting the gentamicin 3-acetyltransferase and kanamycin 6'-acetyltransferase enzymes used in the assay. It interferes with the homogeneous enzyme immunoassays for gentamicin and tobramycin (at concentrations greater than or equal to 105 and greater than or equal to104 USP units/L, respectively), but not with the commercially available homogeneous enzyme immunoassays for other drugs. Heparin interference with the homogeneous enzyme immunoassay for aminoglycosides requires both the heparin polyanion and glucose-6-phosphate dehydrogenase bound to a cationic aminoglycoside. This interference can be reproduced with dextran sulfate (but not dextran), and does not occur with free enzyme (glucose-6-phosphate dehydrogenase) alone. Heparin interference with these two assays and at concentrations that may be present in intravenous infusions or in seriously underfilled blood-collection tubes is described

  1. Identification of Genes Coding Aminoglycoside Modifying Enzymes in E. coli of UTI Patients in India

    Directory of Open Access Journals (Sweden)

    Abdul Rouf Mir

    2016-01-01

    Full Text Available This study is to probe the pattern of antibiotic resistance against aminoglycosides and its mechanism in E. coli obtained from patients from Chennai, India. Isolation and identification of pathogens were done on MacConkey agar. Antimicrobial sensitivity testing was done by disc diffusion test. The identification of genes encoding aminoglycoside modifying enzymes was done by Polymerase Chain Reaction (PCR. Out of 98 isolates, 71 (72.45% isolates were identified as E. coli and the remaining 27 (27.55% as other bacteria. Disc diffusion method results showed a resistance level of 72.15% for streptomycin, 73.4% for gentamicin, 63.26% for neomycin, 57.14% for tobramycin, 47.9% for netilmicin, and 8.16% for amikacin in E. coli. PCR screening showed the presence of four genes, namely, rrs, aacC2, aacA-aphD, and aphA3, in their plasmid DNA. The results point towards the novel mechanism of drug resistance in E. coli from UTI patients in India as they confirm the presence of genes encoding enzymes that cause resistance to aminoglycoside drugs. This could be an alarm for drug prescription to UTI patients.

  2. A rapid method for detection of five known mutations associated with aminoglycoside-induced deafness

    Directory of Open Access Journals (Sweden)

    Greinwald John H

    2009-01-01

    Full Text Available Abstract Background South Africa has one of the highest incidences of multidrug-resistant tuberculosis (MDR-TB in the world. Concomitantly, aminoglycosides are commonly used in this country as a treatment against MDR-TB. To date, at least five mutations are known to confer susceptibility to aminoglycoside-induced hearing loss. The aim of the present study was to develop a rapid screening method to determine whether these mutations are present in the South African population. Methods A multiplex method using the SNaPshot technique was used to screen for five mutations in the MT-RNR1 gene: A1555G, C1494T, T1095C, 961delT+C(n and A827G. A total of 204 South African control samples, comprising 98 Mixed ancestry and 106 Black individuals were screened for the presence of the five mutations. Results A robust, cost-effective method was developed that detected the presence of all five sequence variants simultaneously. In this pilot study, the A1555G mutation was identified at a frequency of 0.9% in the Black control samples. The 961delT+C(n variant was present in 6.6% of the Black controls and 2% of the Mixed ancestry controls. The T1095C, C1494T and A827G variants were not identified in any of the study participants. Conclusion The frequency of 0.9% for the A1555G mutation in the Black population in South Africa is of concern given the high incidence of MDR-TB in this particular ethnic group. Future larger studies are warranted to determine the true frequencies of the aminoglycoside deafness mutations in the general South African population. The high frequencies of the 961delT+C(n variant observed in the controls suggest that this change is a common non-pathogenic polymorphism. This genetic method facilitates the identification of individuals at high risk of developing hearing loss prior to the start of aminoglycoside therapy. This is important in a low-resource country like South Africa where, despite their adverse side-effects, aminoglycosides will

  3. Relationship between antimicrobial resistance and aminoglycoside-modifying enzyme gene expressions in Acinetobacter baumannii

    Institute of Scientific and Technical Information of China (English)

    SHI Wei-feng; JIANG Jian-ping; MI Zu-huang

    2005-01-01

    Background Acinetobacter baumannii is one of the main gram-negative bacilli in clinical practice. Nosocomial infections caused by multi-drug resistance Acinetobacter baumannii is very difficult to treat. This study was designed to investigate the antimicrobial resistance characteristics and four resistant gene expressions of aminoglycoside-modifying enzymes including N-acetyltransferases and O-phosphotransferases in Acinetobacter baumannii. Methods Bacterial identification and antimicrobial susceptibility test were performed by PhoenixTM system in 247 strains of Acinetobacter baumannii. Minimal inhibitory concentrations (MICs) of seven aminoglycosides including gentamicin, amikacin, kanamycin, tobramycin, netilmicin, neomycin and streptomycin in 15 strains of multi-drug resistant Acinetobacter baumannii were detected by agar dilution. Four aminoglycoside-modifying enzyme genes were amplified by polymerase chain reaction (PCR) and verified by DNA sequencer.Results The resistance rates of 247 strains of Acinetobacter baumannii against cefotaxime, levofloxacin, piperacillin, aztreonam, tetracycline, ciprofloxacin and chloramphenicol were more than 50%. Imipenem and meropenem showed high antibacterial activities with resistance rates of 3.2% and 4.1%. MIC50 and MIC90 of gentamicin, amikacin, streptomycin and kanamycin in 15 strains of multi-drug resistant Acinetobacter baumanii were all more than 1024 mg/L, and the resistance rates were 100%, 100%, 100% and 93.3%, respectively. But their resistance rates to tobramycin, netilmicin and neomycin were 86.7%, 93.3% and 46.7%, respectively. Three modifying enzyme genes, including aacC1, aacC2 and aacA4 genes, were found in 15 strains, but aphA6 had not been detected. Their positive rates were 93.3%, 20.0% and 20.0%, respectively. These three genes existed simultaneously in No.19 strain. Nucleotide sequences of aacC1, aacC2 and aacA4 genes shared 100%, 97.9% and 99.7% identities with GenBank genes (AY307113, S68058 and AY

  4. Defining RNA motif-aminoglycoside interactions via two-dimensional combinatorial screening and structure-activity relationships through sequencing.

    Science.gov (United States)

    Velagapudi, Sai Pradeep; Disney, Matthew D

    2013-10-15

    RNA is an extremely important target for the development of chemical probes of function or small molecule therapeutics. Aminoglycosides are the most well studied class of small molecules to target RNA. However, the RNA motifs outside of the bacterial rRNA A-site that are likely to be bound by these compounds in biological systems is largely unknown. If such information were known, it could allow for aminoglycosides to be exploited to target other RNAs and, in addition, could provide invaluable insights into potential bystander targets of these clinically used drugs. We utilized two-dimensional combinatorial screening (2DCS), a library-versus-library screening approach, to select the motifs displayed in a 3×3 nucleotide internal loop library and in a 6-nucleotide hairpin library that bind with high affinity and selectivity to six aminoglycoside derivatives. The selected RNA motifs were then analyzed using structure-activity relationships through sequencing (StARTS), a statistical approach that defines the privileged RNA motif space that binds a small molecule. StARTS allowed for the facile annotation of the selected RNA motif-aminoglycoside interactions in terms of affinity and selectivity. The interactions selected by 2DCS generally have nanomolar affinities, which is higher affinity than the binding of aminoglycosides to a mimic of their therapeutic target, the bacterial rRNA A-site. PMID:23719281

  5. Molecular basis of rare aminoglycoside susceptibility and pathogenesis of Burkholderia pseudomallei clinical isolates from Thailand.

    Directory of Open Access Journals (Sweden)

    Lily A Trunck

    Full Text Available BACKGROUND: Burkholderia pseudomallei is intrinsically resistant to aminoglycosides and macrolides, mostly due to AmrAB-OprA efflux pump expression. We investigated the molecular mechanisms of aminoglycoside susceptibility exhibited by Thai strains 708a, 2188a, and 3799a. METHODOLOGY/PRINCIPAL FINDINGS: qRT-PCR revealed absence of amrB transcripts in 708a and greatly reduced levels in 2188a and 3799a. Serial passage on increasing gentamicin concentrations yielded 2188a and 3799a mutants that became simultaneously resistant to other aminoglycosides and macrolides, whereas such mutants could not be obtained with 708a. Transcript analysis showed that the resistance of the 2188a and 3799a mutants was due to upregulation of amrAB-oprA expression by unknown mechanism(s. Use of a PCR walking strategy revealed that the amrAB-oprA operon was missing in 708a and that this loss was associated with deletion of more than 70 kb of genetic material. Rescue of the amrAB-oprB region from a 708a fosmid library and sequencing showed the presence of a large chromosome 1 deletion (131 kb and 141 kb compared to strains K96243 and 1710b, respectively. This deletion not only removed the amrAB-oprA operon, but also the entire gene clusters for malleobactin and cobalamin synthesis. Other genes deleted included the anaerobic arginine deiminase pathway, putative type 1 fimbriae and secreted chitinase. Whole genome sequencing and PCR analysis confirmed absence of these genes from 708a. Despite missing several putative virulence genes, 708a was fully virulent in a murine melioidosis model. CONCLUSIONS/SIGNIFICANCE: Strain 708a may be a natural candidate for genetic manipulation experiments that use Select Agent compliant antibiotics for selection and validates the use of laboratory-constructed Delta(amrAB-oprA mutants in such experiments.

  6. Mechanism of enhanced activity of liposome-entrapped aminoglycosides against resistant strains of Pseudomonas aeruginosa.

    Science.gov (United States)

    Mugabe, Clement; Halwani, Majed; Azghani, Ali O; Lafrenie, Robert M; Omri, Abdelwahab

    2006-06-01

    Pseudomonas aeruginosa is inherently resistant to most conventional antibiotics. The mechanism of resistance of this bacterium is mainly associated with the low permeability of its outer membrane to these agents. We sought to assess the bactericidal efficacy of liposome-entrapped aminoglycosides against resistant clinical strains of P. aeruginosa and to define the mechanism of liposome-bacterium interactions. Aminoglycosides were incorporated into liposomes, and the bactericidal efficacies of both free and liposomal drugs were evaluated. To define the mechanism of liposome-bacterium interactions, transmission electron microscopy (TEM), flow cytometry, lipid mixing assay, and immunocytochemistry were employed. Encapsulation of aminoglycosides into liposomes significantly increased their antibacterial activity against the resistant strains used in this study (MICs of > or =32 versus < or =8 microg/ml). TEM observations showed that liposomes interact intimately with the outer membrane of P. aeruginosa, leading to the membrane deformation. The flow cytometry and lipid mixing assays confirmed liposome-bacterial membrane fusion, which increased as a function of incubation time. The maximum fusion rate was 54.3% +/- 1.5% for an antibiotic-sensitive strain of P. aeruginosa and 57.8% +/- 1.9% for a drug-resistant strain. The fusion between liposomes and P. aeruginosa significantly enhanced the antibiotics' penetration into the bacterial cells (3.2 +/- 2.3 versus 24.2 +/- 6.2 gold particles/bacterium, P < or = 0.001). Our data suggest that liposome-entrapped antibiotics could successfully resolve infections caused by antibiotic-resistant P. aeruginosa through an enhanced mechanism of drug entry into the bacterial cells. PMID:16723560

  7. Phytochemical screening and synergistic interactions between aminoglycosides, selected antibiotics and extracts from the bryophyte Octoblepharum albidum Hedw (Calymperaceae

    Directory of Open Access Journals (Sweden)

    Vidal C.A.S.

    2012-01-01

    Full Text Available This work is the first to describe the modulation of antibiotic activity of the bryophyte Octoblepharum albidum Hedw extract. The antibacterial activity of ethanolic extract of O. albidum (EEOa, alone and in association with aminoglycosides, was determined against six bacterial strains by a microdilution test. The results showed a similar inhibitory activity of EEOa against Escherichia coli ATCC 25922 and Klebsiella pneumoniae ATCC 33018 (MICs 512 μg/mL. The synergistic effect of the extracts and aminoglycosides was also verified. The most pronounced effects were obtained with EEOa + gentamicin against E. coli and EEOa + kanamycin against K. pneumoniae with MICs reduction (128 to 32 μg/mL. The data from this study are indicative of the antibacterial activity of the bryophyte O. albidum extracts and its potential in modifying the resistance of aminoglycosides analyzed.

  8. Synthesis of 4′-aminopantetheine and derivatives to probe aminoglycoside N-6′-acetyltransferase

    Science.gov (United States)

    Yan, Xuxu; Akinnusi, T. Olukayode; Larsen, Aaron T.; Auclair, Karine

    2011-01-01

    Summary A convenient synthesis of 4′-aminopantetheine from commercial D-pantethine is reported. The amino group was introduced by reductive amination in order to avoid substitution at a sterically congested position. Derivatives of 4′-aminopantetheine were also prepared to evaluate the effect of O-to-N substitution on inhibitors of the resistance-causing enzyme aminoglycoside N-6′-acetyltransferase. The biological results combined with docking studies indicate that in spite of its reported unusual flexibility and ability to adopt different folds, this enzyme is highly specific for AcCoA. PMID:21225062

  9. Synthesis of 4'-aminopantetheine and derivatives to probe aminoglycoside N-6'-acetyltransferase.

    Science.gov (United States)

    Yan, Xuxu; Akinnusi, T Olukayode; Larsen, Aaron T; Auclair, Karine

    2011-03-01

    A convenient synthesis of 4'-aminopantetheine from commercial D-pantethine is reported. The amino group was introduced by reductive amination in order to avoid substitution at a sterically congested position. Derivatives of 4'-aminopantetheine were also prepared to evaluate the effect of O-to-N substitution on inhibitors of the resistance-causing enzyme aminoglycoside N-6'-acetyltransferase. The biological results combined with docking studies indicate that in spite of its reported unusual flexibility and ability to adopt different folds, this enzyme is highly specific for AcCoA. PMID:21225062

  10. Worldwide Disseminated armA Aminoglycoside Resistance Methylase Gene Is Borne by Composite Transposon Tn1548

    OpenAIRE

    Galimand, M.; Sabtcheva, S.; Courvalin, P; Lambert, T.

    2005-01-01

    The armA (aminoglycoside resistance methylase) gene, which confers resistance to 4,6-disubstituted deoxystreptamines and fortimicin, was initially found in Klebsiella pneumoniae BM4536 on IncL/M plasmid pIP1204 of ca. 90 kb which also encodes the extended-spectrum β-lactamase CTX-M-3. Thirty-four enterobacteria from various countries that were likely to produce a CTX-M enzyme since they were more resistant to cefotaxime than to ceftazidime were studied. The armA gene was detected in 12 clinic...

  11. Correction of ATM gene function by aminoglycoside-induced read-through of premature termination codons

    OpenAIRE

    Lai, Chih-Hung; Chun, Helen H.; Nahas, Shareef A.; Mitui, Midori; Gamo, Kristin M.; Du, Liutao; Gatti, Richard A.

    2004-01-01

    Approximately 14% of genetic mutations in patients with ataxia-telangiectsia (A-T) are single-nucleotide changes that result in primary premature termination codons (PTCs), either UAA, UAG, or UGA. The purpose of this study was to explore a potential therapeutic approach for this subset of patients by using aminoglycosides to induce PTC read-through, thereby restoring levels of full-length ATM (A-T mutated) protein. In experiments using a modified in vitro cDNA coupled transcription/translati...

  12. Design of Novel Aminoglycoside Derivatives with Enhanced Suppression of Diseases-Causing Nonsense Mutations.

    Science.gov (United States)

    Sabbavarapu, Narayana Murthy; Shavit, Michal; Degani, Yarden; Smolkin, Boris; Belakhov, Valery; Baasov, Timor

    2016-04-14

    New pseudotrisaccharide derivatives of aminoglycosides that exploit additional interaction on the shallow groove face of the decoding-site rRNA of eukaryotic ribosome were designed, synthesized and biologically evaluated. Novel lead structures (6 and 7 with an additional 7'-OH), exhibiting enhanced specificity to eukaryotic cytoplasmic ribosome, and superior nonsense mutation suppression activity than those of gentamicin, were discovered. The comparative benefit of new leads was demonstrated in four different nonsense DNA-constructs underling the genetic diseases cystic fibrosis, Usher syndrome, and Hurler syndrome. PMID:27096052

  13. Clonal origin of aminoglycoside-resistant Citrobacter freundii isolates in a Danish county

    DEFF Research Database (Denmark)

    Norskov-Lauritsen, N.; Sandvang, Dorthe; Hedegaard, J.; Fussing, V.; Mortensen, K.K.; Sperling-Petersen, H.U.; Schonheyder, H.C.

    2001-01-01

    During 1997, attention was drawn to an increased frequency of aminoglycoside-resistant Citrobacter freundii in a Danish county, when a total of 24 resistant C. freundii isolates was detected. In this study, 15 such isolates were typed by pulsed-field gel electrophoresis, riboprinting and partial ...... dihydrofolate reductase gene in a class I integron. The source of the strain remains unresolved. Representative isolates were obtained from various specimens from hospitals and general practice throughout the county, with no evidence of patient-to-patient transmission....

  14. Crystallization and preliminary crystallographic analysis of an aminoglycoside kinase from Legionella pneumophila

    International Nuclear Information System (INIS)

    Two crystal forms of the antibiotic resistance enzyme APH(9)-Ia from L. pneumophila are reported. 9-Aminoglycoside phosphotransferase type Ia [APH(9)-Ia] is a resistance factor in Legionella pneuemophila, the causative agent of legionnaires’ disease. It is responsible for providing intrinsic resistance to the antibiotic spectinomycin. APH(9)-Ia phosphorylates one of the hydroxyl moieties of spectinomycin in an ATP-dependent manner, abolishing the antibiotic properties of this drug. Here, the crystallization and preliminary X-ray studies of this enzyme in two crystal forms is reported. One of the these crystal forms provides diffraction data to a resolution of 1.7 Å

  15. Structural and molecular basis for resistance to aminoglycoside antibiotics by the adenylyltransferase ANT(2″)-Ia.

    Science.gov (United States)

    Cox, Georgina; Stogios, Peter J; Savchenko, Alexei; Wright, Gerard D

    2015-01-01

    The aminoglycosides are highly effective broad-spectrum antimicrobial agents. However, their efficacy is diminished due to enzyme-mediated covalent modification, which reduces affinity of the drug for the target ribosome. One of the most prevalent aminoglycoside resistance enzymes in Gram-negative pathogens is the adenylyltransferase ANT(2″)-Ia, which confers resistance to gentamicin, tobramycin, and kanamycin. Despite the importance of this enzyme in drug resistance, its structure and molecular mechanism have been elusive. This study describes the structural and mechanistic basis for adenylylation of aminoglycosides by the ANT(2″)-Ia enzyme. ANT(2″)-Ia confers resistance by magnesium-dependent transfer of a nucleoside monophosphate (AMP) to the 2″-hydroxyl of aminoglycoside substrates containing a 2-deoxystreptamine core. The catalyzed reaction follows a direct AMP transfer mechanism from ATP to the substrate antibiotic. Central to catalysis is the coordination of two Mg(2+) ions, positioning of the modifiable substrate ring, and the presence of a catalytic base (Asp86). Comparative structural analysis revealed that ANT(2″)-Ia has a two-domain structure with an N-terminal active-site architecture that is conserved among other antibiotic nucleotidyltransferases, including Lnu(A), LinB, ANT(4')-Ia, ANT(4″)-Ib, and ANT(6)-Ia. There is also similarity between the nucleotidyltransferase fold of ANT(2″)-Ia and DNA polymerase β. This similarity is consistent with evolution from a common ancestor, with the nucleotidyltransferase fold having adapted for activity against chemically distinct molecules. IMPORTANCE  : To successfully manage the threat associated with multidrug-resistant infectious diseases, innovative therapeutic strategies need to be developed. One such approach involves the enhancement or potentiation of existing antibiotics against resistant strains of bacteria. The reduction in clinical usefulness of the aminoglycosides is a particular

  16. Cymbopogon citratus protects against the renal injury induced by toxic doses of aminoglycosides in rabbits

    Directory of Open Access Journals (Sweden)

    N Ullah

    2013-01-01

    Full Text Available Renal injury is the most common side-effect of aminoglycosides. These antimicrobial drugs are particularly effective against Gram-negative microorganisms. The present study was conducted to investigate the renal protective activity of Cymbopogon citratus in gentamicin-induced nephrotoxicity. Male rabbits were divided into four groups (n=6 including group 1 (0.9% saline treated, group 2 (80 mg/kg/day gentamicin-treated, group 3 (200 mg/kg/day Cymbopogon citratus treated and group 4 (80 mg/kg/day gentamicin and 200 mg/kg/day Cymbopogon citratus treated. Biochemical kidney functioning parameters, urinary enzymes and histopathological examination were performed. The results of the present study showed that simultaneous administration of Cymbopogon citrates and gentamicin significantly protected alteration in body weight, blood urea nitrogen, serum creatinine, creatinine clearance, serum uric acid, serum electrolytes, urinary volume, urinary protein, urinary lactate dehydrogenase and urinary alkaline phosphatase induced by gentamicin. Histological examination of the kidney also suggested the same. It is concluded from the current study that co-administration of Cymbopogon citratus with gentamicin for 3 weeks successfully prevented renal damage associated with aminoglycosides.

  17. Cymbopogon citratus Protects against the Renal Injury Induced by Toxic Doses of Aminoglycosides in Rabbits.

    Science.gov (United States)

    Ullah, N; Khan, M A; Khan, T; Ahmad, W

    2013-03-01

    Renal injury is the most common side-effect of aminoglycosides. These antimicrobial drugs are particularly effective against Gram-negative microorganisms. The present study was conducted to investigate the renal protective activity of Cymbopogon citratus in gentamicin-induced nephrotoxicity. Male rabbits were divided into four groups (n=6) including group 1 (0.9% saline treated), group 2 (80 mg/kg/day gentamicin-treated), group 3 (200 mg/kg/day Cymbopogon citratus treated) and group 4 (80 mg/kg/day gentamicin and 200 mg/kg/day Cymbopogon citratus treated). Biochemical kidney functioning parameters, urinary enzymes and histopathological examination were performed. The results of the present study showed that simultaneous administration of Cymbopogon citrates and gentamicin significantly protected alteration in body weight, blood urea nitrogen, serum creatinine, creatinine clearance, serum uric acid, serum electrolytes, urinary volume, urinary protein, urinary lactate dehydrogenase and urinary alkaline phosphatase induced by gentamicin. Histological examination of the kidney also suggested the same. It is concluded from the current study that co-administration of Cymbopogon citratus with gentamicin for 3 weeks successfully prevented renal damage associated with aminoglycosides. PMID:24019578

  18. Indigenous and acquired modifications in the aminoglycoside binding sites of Pseudomonas aeruginosa rRNAs

    DEFF Research Database (Denmark)

    Gutierrez, Belen; Douthwaite, Stephen Roger; Gonzalez-Zorn, Bruno

    2013-01-01

    of 16S rRNA helix 44 with a secondary target in 23S rRNA helix 69. Here, we have mapped P. aeruginosa rRNAs using MALDI mass spectrometry and reverse transcriptase primer extension to identify nucleotide modifications that could influence aminoglycoside interactions. Helices 44 and 45 contain...... indigenous (housekeeping) modifications at m (4)Cm1402, m (3)U1498, m (2)G1516, m (6) 2A1518, and m (6) 2A1519; helix 69 is modified at m (3)Ψ1915, with m (5)U1939 and m (5)C1962 modification in adjacent sequences. All modifications were close to stoichiometric, with the exception of m (3)Ψ1915, where about...... 80% of rRNA molecules were methylated. The modification status of a virulent clinical strain expressing the acquired methyltransferase RmtD was altered in two important respects: RmtD stoichiometrically modified m (7)G1405 conferring high resistance to the aminoglycoside tobramycin and, in doing so...

  19. Assessment of hearing loss in multi-drug resistant tuberculosis (MDR-TB patients undergoing Aminoglycoside treatment

    Directory of Open Access Journals (Sweden)

    Sheikh Nizamuddin

    2015-07-01

    Conclusion: Aminoglycosides in MDR-TB patients may cause irreversible hearing loss involving higher frequencies and can become a hearing handicap as speech frequencies are too implied in more or less of the patients, thus underlining the need for regular audiologic evaluation in patients of MDR-TB during the treatment. [Int J Res Med Sci 2015; 3(7.000: 1734-1740

  20. Purification, crystallization and preliminary X-ray analysis of the aminoglycoside-6′-acetyltransferase AAC(6′)-Im

    OpenAIRE

    Toth, Marta; Vakulenko, Sergei B.; Smith, Clyde A.

    2012-01-01

    AAC(6′)-Im is an N-acetyltransferase enzyme responsible for aminoglycoside resistance in E. faecium and E. coli isolates. Crystals of the kanamycin complex of this enzyme have been prepared and preliminary X-ray diffraction experiments have been undertaken.

  1. Purification, crystallization and preliminary X-ray analysis of the aminoglycoside-6′-acetyltransferase AAC(6′)-Im

    International Nuclear Information System (INIS)

    AAC(6′)-Im is an N-acetyltransferase enzyme responsible for aminoglycoside resistance in E. faecium and E. coli isolates. Crystals of the kanamycin complex of this enzyme have been prepared and preliminary X-ray diffraction experiments have been undertaken. Bacterial resistance to the aminoglycoside antibiotics is primarily the result of enzymatic deactivation of the drugs. The aminoglycoside N-acetyltransferases (AACs) are a large family of bacterial enzymes that are responsible for coenzyme-A-facilitated acetylation of aminoglycosides. The gene encoding one of these enzymes, AAC(6′)-Im, has been cloned and the protein (comprising 178 amino-acid residues) was expressed in Escherichia coli, purified and crystallized as the kanamycin complex. Synchrotron diffraction data to approximately 2.0 Å resolution were collected from a crystal of this complex on beamline BL12-2 at SSRL (Stanford, California, USA). The crystals belonged to the hexagonal space group P65, with approximate unit-cell parameters a = 107.75, c = 37.33 Å, and contained one molecule in the asymmetric unit. Structure determination is under way using molecular replacement

  2. Identification of aminoglycoside-acetylating enzymes by high-pressure liquid chromatographic determination of their reaction products.

    OpenAIRE

    Lovering, A M; White, L. O.; Reeves, D S

    1984-01-01

    A method to identify the aminoglycoside-acetyltransferase (AAC) enzymes AAC(3), AAC(2') and AAC(6') by high-pressure liquid chromatographic characterization of their products of reaction with tobramycin or sisomicin is described. Conditions are given for the chromatography of kanamycin A, netilmicin, neomycin, and apramycin, and their products of reaction, if any, with the three AAC enzymes are listed.

  3. Audiologic monitoring of multi-drug resistant tuberculosis patients on aminoglycoside treatment with long term follow-up

    Directory of Open Access Journals (Sweden)

    Sarkar Malay

    2007-11-01

    Full Text Available Abstract Background Multi-drug resistant tuberculosis has emerged as a significant problem with the resurfacing of tuberculosis and thus the need to use the second line drugs with the resultant increased incidence of adverse effects. We discuss the effect of second line aminoglycoside anti-tubercular drugs on the hearing status of MDR-TB patients. Methods Sixty four patients were put on second line aminoglycoside anti-TB drugs. These were divided into three groups: group I, 34 patients using amikacin, group II, 26 patients using kanamycin and group III, 4 patients using capreomycin. Results Of these, 18.75% of the patients developed sensorineural hearing loss involving higher frequencies while 6.25% had involvement of speech frequencies also. All patients were seen again approximately one year after aminoglycoside discontinuation and all hearing losses were permanent with no threshold improvement. Conclusion Aminoglycosides used in MDR-TB patients may result in irreversible hearing loss involving higher frequencies and can become a hearing handicap as speech frequencies are also involved in some of the patients thus underlining the need for regular audiologic evaluation in patients of MDR-TB during the treatment.

  4. Non-derivatization approach to high-performance liquid chromatography-fluorescence detection for aminoglycoside antibiotics based on a ligand displacement reaction.

    Science.gov (United States)

    Yang, M; Tomellini, S A

    2001-12-21

    An indirect fluorescence detection method has been developed for detecting the aminoglycoside antibiotics following chromatographic separation. This approach to detection is based on a displacement reaction between the aminoglycosides and a copper(II)-L-tryptophan (L-Trp) complex, Cu(L-Trp)2. The aminoglycosides, which contain multiple amino groups, have strong affinities for the Cu(II) ion and displace L-Trp from the Cu(L-Trp)2 complex. The resulting increase in L-Trp fluorescence, which is quenched when coordinated to Cu(II), is indicative of the presence of the aminoglycoside. Fluorescence titration data indicate that there is a stoichiometric ratio of 1:1 between the reaction of the aminoglycosides with Cu(L-Trp)2. This HPLC detection scheme is implemented postcolumn by mixing a buffered Cu(L-Trp)2 solution with the column eluent prior to detection. The aminoglycosides were separated with the use of a column packed with a polymeric strong cation-exchanger. Separation and detection variables were optimized and are discussed. The detection limits for the aminoglycosides tested ranged from 4.2 to 14.5 ng injected (S/N=3). A linear working curve was achieved for amikacin in the range of 29-586 ng for a six point linearity test. The developed separation and detection scheme was further tested by analyzing commercial pharmaceutical formulations of these antibiotics. PMID:11806546

  5. Determination of stability constants of aminoglycoside antibiotics with their metal complexes

    Science.gov (United States)

    Tiwow, Vanny M. A.

    2014-03-01

    One group of aminoglycoside antibiotics contains aminosugars. The aminosugar neomycin B with its derivate product neamine (2-Deoxy-4-0-(2,6-diamino-2,6-dideoxy-α-D-glucopyranosyl)-D-Streptamine) was identified as a free ligands and metal complexes. In particular, the stability constants of metal complexes by potentiometric titration techniques were investigated. Our previous study had determined the acid dissociation constants of these aminosugars with few metal complexes in fair depth. In this work, the complexation of two pyridine-containing amino alcohols and an amino sugar (neamine) have been measured potentiometrically. For instance, the stability constant of copper(II) complexation were determine and the model system generated an excellent fit. Stability constants with several metals have been determined and will be reported.

  6. Study of the Interference between Plectranthus Species Essential Oils from Brazil and Aminoglycosides.

    Science.gov (United States)

    Galvão Rodrigues, Fabíola Fernandes; Costa, José Galberto Martins; Rodrigues, Fábio Fernandes Galvao; Campos, Adriana Rolim

    2013-01-01

    Plectranthus is one of the most representative genera of Lamiaceae family. In this study, the essential oils from Plectranthus amboinicus, Plectranthus ornatus, and Plectranthus barbatus were investigated for their chemical composition and antimicrobial and modulatory activities. The major components found were carvacrol (54.4%-P. amboinicus) and eugenol (22.9%-P. ornatus e 25.1%-P. barbatus). In vitro antimicrobial activity was conducted against Escherichia coli, Proteus vulgaris, Bacillus cereus, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus aureus (multiresistant) using microdilution method. The results of bioassay showed that all strains were sensitive to the oils, except P. aeruginosa that was resistant to P. amboinicus and P. ornatus. A synergistic effect of all essential oils combined with the aminoglycosides was demonstrated. These results show that P. amboinicus, P. ornatus, and P. barbatus inhibit the growth of pathogenic microorganism, and besides this they present antibiotic modifying activity, providing a new perspective against the problem of bacterial resistance to antibiotics. PMID:23662150

  7. Coenzyme A Binding to the Aminoglycoside Acetyltransferase (3)-IIIb Increases Conformational Sampling of Antibiotic Binding Site

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Xiaohu [ORNL; Norris, Adrianne [University of Tennessee, Knoxville (UTK); Baudry, Jerome Y [ORNL; Serpersu, Engin H [University of Tennessee, Knoxville (UTK)

    2011-01-01

    NMR spectroscopy experiments and molecular dynamics simulations were performed to describe the dynamic properties of the aminoglycoside acetyltransferase (3)-IIIb (AAC) in its apo and coenzyme A (CoASH) bound forms. The {sup 15}N-{sup 1}H HSQC spectra indicate a partial structural change and coupling of the CoASH binding site with another region in the protein upon the CoASH titration into the apo enzyme. Molecular dynamics simulations indicate a significant structural and dynamic variation of the long loop in the antibiotic binding domain in the form of a relatively slow (250 ns), concerted opening motion in the CoASH enzyme complex and that binding of the CoASH increases the structural flexibility of the loop, leading to an interchange between several similar equally populated conformations.

  8. Factors impacting the aminoglycoside-induced UGA stop codon readthrough in selenoprotein translation.

    Science.gov (United States)

    Martitz, Janine; Hofmann, Peter Josef; Johannes, Jörg; Köhrle, Josef; Schomburg, Lutz; Renko, Kostja

    2016-09-01

    Aminoglycosides (AG) are oligosaccharide antibiotics that interfere with the small ribosomal subunit in aerobic, Gram-negative bacteria, causing pathogen-destructing error rates in their protein biosynthesis. Aminoglycosides also induce mRNA misinterpretation in eukaryotic cells, especially of the UGA (Opal)-stop codon, albeit to a lower extent. UGA recoding is essentially required for the incorporation of selenocysteine (Sec) into growing selenoproteins during translation. Selenocysteine incorporation requires the presence of a selenoprotein-specific stem-loop structure within the 3'-untranslated region of the mRNA, the so-called Sec-insertion sequence (SECIS) element. Interestingly, selenoprotein genes differ in their SECIS-element sequence and in their UGA base context. We hypothesized that the SECIS-element and the specific codon context synergize in controlling the effects of AG on stop codon readthrough. To this end, the SECIS-elements of glutathione peroxidase 1, glutathione peroxidase 4 and selenoprotein P transcripts were cloned into a reporter system and analyzed in combination with different UGA codon contexts. Our results indicate that a cytosine in position 4 (directly downstream of UGA) confers strongest effects on both the Se- and AG-dependent readthrough. Overall selenoprotein biosynthesis rate depends on the Se-status, AG concentration and the specific SECIS-element present in the transcript. These findings help to get a better understanding for the susceptibility of different transcripts towards AG-mediated interference with the biosynthesis of functional Se-containing selenoproteins, and highlight the importance of the Se-status for successful selenoprotein biosynthesis under antibiotic therapy. PMID:27157664

  9. Investigation on the Mechanism of Exacerbation of Myasthenia Gravis by Aminoglycoside Antibiotics in Mouse Model

    Institute of Scientific and Technical Information of China (English)

    LIU Changqin; HU Fang

    2005-01-01

    Summary: To investigate the underlying mechanism of the exacerbation of myasthenia gravis by aminoglycoside antibiotics. C57/BL6 mice were immunized with acetylcholine receptor (AChR), extracted from electric organ of Narcine timilei according to Xu Haopeng's methods, in complete Fruend's adjuvant (CFA) to establish experimental autoimmune myasthenia gravis (EAMG). EAMG mice were divided randomly into 5 groups: MG group, NS group and three antibiotics groups. The clinical symptom scores of mice were evaluated on d7 after the last immunization and d14 of antibiotics treatment. Repetitive nerve stimulation (RNS) was performed and the levels of anti-AChR antibody (AChR-Ab) were tested at the same time. The mean clinical symptom grades of gentamycin group (1.312, 2.067), amikacin group (1.111, 1.889) and etimicin group (1.263, 1.632) were significantly higher than those of MG group (1.000, 1.200) (P<0.05). The positive rates of RNS of three antibiotics groups were 69.23 %, 58.82 % and 63.16 % respectively, which were significantly higher than those of MG group and NS group (40.00 %, 40.00 %, P<0.05). The AChR-Ab level in serum and the expression of AChR on neuromuscular junction (NMJ) of mice in three antibiotics groups were also higher than those of MG group. Our results indicated that aminoglycoside antibiotics could aggravate the symptom of myasthenia gravis. The exacerbation of myasthenia gravis by these antibiotics probably involves competitively restraining the release of acetylcholine from presynaptic membrane, impairing the depolarization of postsynaptic membrane, depressing the irritability of myocyte membrane around the end-plate membrane and consequently leading to the blockade of neuromuscular junction.

  10. Azobenzene-aminoglycoside: Self-assembled smart amphiphilic nanostructures for drug delivery.

    Science.gov (United States)

    Deka, Smriti Rekha; Yadav, Santosh; Mahato, Manohar; Sharma, Ashwani Kumar

    2015-11-01

    Here, we have designed and synthesized a novel cationic amphiphilic stimuli-responsive azobenzene-aminoglycoside (a small molecule) conjugate, Azo-AG 5, and characterized it by UV and FTIR. Light responsive nature of Azo-AG 5 was assessed under UV-vis light. Self- assembly of Azo-AG 5 in aqueous solutions into nanostructures and their ability to act as drug carrier were also investigated. The nanostructures of Azo-AG 5 showed average hydrodynamic diameter of ∼ 255 nm with aminoglycoside moiety (neomycin) and 4-dimethylaminoazobenzene forming hydrophilic shell and hydrophobic core, respectively. In the hydrophobic core, eosin and aspirin were successfully encapsulated. Dynamic light scattering (DLS) measurements demonstrated that the nanoassemblies showed expansion and contraction on successive UV and visible light irradiations exhibiting reversible on-off switch for controlling the drug release behavior. Similar behavior was observed when these nanostructures were subjected to pH-change. In vitro drug release studies showed a difference in UV and visible light-mediated release pattern. It was observed that the release rate under UV irradiation was comparatively higher than that observed under visible light. Further, azoreductase-mediated cleavage of the azo moiety in Azo-AG 5 nanoassemblies resulted in the dismantling of the structures into aggregated microstructures. Azo-AG 5 nanostructures having positive surface charge (+9.74 mV) successfully interacted with pDNA and retarded its mobility on agarose gel. Stimuli responsiveness of nanostructures and their on-off switch like behavior ensure the great potential as controlled drug delivery systems and in other biomedical applications such as colon-specific delivery and gene delivery. PMID:26255160

  11. Ribozyme-based aminoglycoside switches of gene expression engineered by genetic selection in S. cerevisiae.

    Science.gov (United States)

    Klauser, Benedikt; Atanasov, Janina; Siewert, Lena K; Hartig, Jörg S

    2015-05-15

    Systems for conditional gene expression are powerful tools in basic research as well as in biotechnology. For future applications, it is of great importance to engineer orthogonal genetic switches that function reliably in diverse contexts. RNA-based switches have the advantage that effector molecules interact immediately with regulatory modules inserted into the target RNAs, getting rid of the need of transcription factors usually mediating genetic control. Artificial riboswitches are characterized by their simplicity and small size accompanied by a high degree of modularity. We have recently reported a series of hammerhead ribozyme-based artificial riboswitches that allow for post-transcriptional regulation of gene expression via switching mRNA, tRNA, or rRNA functions. A more widespread application was so far hampered by moderate switching performances and a limited set of effector molecules available. Here, we report the re-engineering of hammerhead ribozymes in order to respond efficiently to aminoglycoside antibiotics. We first established an in vivo selection protocol in Saccharomyces cerevisiae that enabled us to search large sequence spaces for optimized switches. We then envisioned and characterized a novel strategy of attaching the aptamer to the ribozyme catalytic core, increasing the design options for rendering the ribozyme ligand-dependent. These innovations enabled the development of neomycin-dependent RNA modules that switch gene expression up to 25-fold. The presented aminoglycoside-responsive riboswitches belong to the best-performing RNA-based genetic regulators reported so far. The developed in vivo selection protocol should allow for sampling of large sequence spaces for engineering of further optimized riboswitches. PMID:24871672

  12. Effects of F171 Mutations in the 6′-N-Acetyltransferase Type Ib [AAC(6′)-Ib] Enzyme on Susceptibility to Aminoglycosides

    OpenAIRE

    Chavideh, Ramona; Sholly, Steven; Panaite, Doina; Tolmasky, Marcelo E.

    1999-01-01

    Substitutions at position F171 of 6′-N-acetyltransferase type Ib cause variable loss of aminoglycoside resistance, indicating that this residue plays an important role in the structure and/or function of the enzyme.

  13. Intrinsic resistance to aminoglycosides in Enterococcus faecium is conferred by the 16S rRNA m5C1404-specific methyltransferase EfmM

    DEFF Research Database (Denmark)

    Galimand, Marc; Schmitt, Emmanuelle; Panvert, Michel; Desmolaize, Benoît; Douthwaite, Stephen Roger; Mechulam, Yves; Courvalin, Patrice

    2011-01-01

    Aminoglycosides are ribosome-targeting antibiotics and a major drug group of choice in the treatment of serious enterococcal infections. Here we show that aminoglycoside resistance in Enterococcus faecium strain CIP 54-32 is conferred by the chromosomal gene efmM, encoding the E. faecium methyltr......Aminoglycosides are ribosome-targeting antibiotics and a major drug group of choice in the treatment of serious enterococcal infections. Here we show that aminoglycoside resistance in Enterococcus faecium strain CIP 54-32 is conferred by the chromosomal gene efmM, encoding the E. faecium...... locations are required for catalysis. The tertiary structure of EfmM is highly similar to that of RsmF, consistent with m(5)C formation at adjacent sites on the 30S subunit, while distinctive structural features account for the enzymes' respective specificities for nucleotides C1404 and C1407....

  14. Aminoglycoside 6′-N-Acetyltransferase Variants of the Ib Type with Altered Substrate Profile in Clinical Isolates of Enterobacter cloacae and Citrobacter freundii

    OpenAIRE

    Casin, Isabelle; Bordon, Florence; Bertin, Philippe; Coutrot, Anne; Podglajen, Isabelle; Brasseur, Robert; Collatz, Ekkehard

    1998-01-01

    Three clinical isolates, Enterobacter cloacae EC1562 and EC1563 and Citrobacter freundii CFr564, displayed an aminoglycoside resistance profile evocative of low-level 6′-N acetyltransferase type II [AAC(6′)-II] production, which conferred reduced susceptibility to gentamicin but not to amikacin or isepamicin. Aminoglycoside acetyltransferase assays suggested the synthesis in the three strains of an AAC(6′) which acetylated amikacin practically as well as it acetylated gentamicin in vitro. Bot...

  15. Aminoglycoside binding to the HIV-1 RNA dimerization initiation site: thermodynamics and effect on the kissing-loop to duplex conversion

    OpenAIRE

    Bernacchi, Serena; Freisz, Séverine; Maechling, Clarisse; Spiess, Bernard; Marquet, Roland; Dumas, Philippe; Ennifar, Eric

    2007-01-01

    Owing to a striking, and most likely fortuitous, structural and sequence similarity with the bacterial 16 S ribosomal A site, the RNA kissing-loop complex formed by the HIV-1 genomic RNA dimerization initiation site (DIS) specifically binds 4,5-disubstituted 2-deoxystreptamine (2-DOS) aminoglycoside antibiotics. We used chemical probing, molecular modeling, isothermal titration calorimetry (ITC) and UV melting to investigate aminoglycoside binding to the DIS loop–loop complex. We showed that ...

  16. Isolation and speciation of Enterococci from various clinical samples and their antimicrobial susceptibility pattern with special reference to high level Aminoglycoside resistance

    Directory of Open Access Journals (Sweden)

    :Saroj Golia, Nirmala AR, Asha S Kamath B

    2014-07-01

    Full Text Available Background and Objectives: Enterococci are important nosocomial agents and strains resistant to penicillin and other antibiotics occur frequently. Enterococci are intrinsically resistant to cephalosporins and offer low level resistance to aminoglycosides. In penicillin sensitive strains, synergism occurs with combination treatment with penicillin and aminoglycoside. Serious infections caused by them are treated with penicillin and aminoglycoside combination. But the synergistic effect is lost, when the strain develops high level aminoglycoside resistance. The choice of drug for infections due to such strains is vancomycin. The present study was carried out to isolate and speciate Enterococci from various clinical samples, to know the susceptibility pattern of the isolates, to determine the High Level Aminoglycoside Resistance (HLAR among Enterococcal isolates. Methods: A total of One hundred Enterococcal species isolated from various clinical samples were identified by various biochemical reactions. Antimicrobial susceptibility testing and HLAR were determined by Kirby- Bauer disc diffusion method. Results: Out of 100 Enterococcal isolates, 59 were E. faecalis, 38 were E. faecium, 3 were other Enterococcal species. Among these 53 isolates showed High Level Aminoglycoside Resistance. Conclusion: Present study shows the presence of drug resistance to most of commonly used antibiotics and HLAR is also more in E.faecium compared to E.fecalis.

  17. The prevalence of aminoglycoside-modifying enzyme genes (aac (6'-I, aac (6'-II, ant (2"-I, aph (3'-VI in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Farzam Vaziri

    2011-01-01

    Full Text Available INTRODUCTION: Pseudomonas aeruginosa (P. aeruginosa is one of the primary opportunistic pathogens responsible for nosocomial infections. Aminoglycosides are an import ant component of antipseudomonal chemotherapy. The inactivation of drugs by modifying enzymes is the most common mechanism of aminoglycoside resistance. OBJECTIVES: The inactivation of aminoglycosides by modifying enzymes is the primary resistance mechanism employed by P. aeruginosa. The aim of the present study was to investigate the occurrence of aminoglycoside resistance and the prevalence of four import ant modifying enzyme genes (aac (6'-I, aac (6'-II, ant (2"-I, aph (3'-VI in P. aeruginosa in Iran. METHODS: A total of 250 clinical isolates of P. aeruginosa were collected from several hospitals in seven cities in Iran. Antimicrobial susceptibility tests (using the disk diffusion method and E-tests were performed for all 250 isolates. In addition, all isolates were screened for the presence of modifying enzyme genes by polymerase chain reaction. RESULTS: The resistance rates, as determined by the disk diffusion method, were as follows: gentamicin 43%, tobramycin 38%, and amikacin 24%. Of the genes examined, aac (6'-II (36% was the most frequently identified gene in phenotypic resist ant isolates, followed by ant (2"-I, aph (3'-VI, and aac (6'-I. CONCLUSIONS: Aminoglycoside resistance in P. aeruginosa remains a signific ant problem in Iran. Therefore, there is considerable local surveillance of aminoglycoside resistance.

  18. Aminoglycoside binding to the HIV-1 RNA dimerization initiation site: thermodynamics and effect on the kissing-loop to duplex conversion.

    Science.gov (United States)

    Bernacchi, Serena; Freisz, Séverine; Maechling, Clarisse; Spiess, Bernard; Marquet, Roland; Dumas, Philippe; Ennifar, Eric

    2007-01-01

    Owing to a striking, and most likely fortuitous, structural and sequence similarity with the bacterial 16 S ribosomal A site, the RNA kissing-loop complex formed by the HIV-1 genomic RNA dimerization initiation site (DIS) specifically binds 4,5-disubstituted 2-deoxystreptamine (2-DOS) aminoglycoside antibiotics. We used chemical probing, molecular modeling, isothermal titration calorimetry (ITC) and UV melting to investigate aminoglycoside binding to the DIS loop-loop complex. We showed that apramycin, an aminoglycoside containing a bicyclic moiety, also binds the DIS, but in a different way than 4,5-disubstituted 2-DOS aminoglycosides. The determination of thermodynamic parameters for various aminoglycosides revealed the role of the different rings in the drug-RNA interaction. Surprisingly, we found that the affinity of lividomycin and neomycin for the DIS (K(d) approximately 30 nM) is significantly higher than that obtained in the same experimental conditions for their natural target, the bacterial A site (K(d) approximately 1.6 microM). In good agreement with their respective affinity, aminoglycoside increase the melting temperature of the loop-loop interaction and also block the conversion from kissing-loop complex to extended duplex. Taken together, our data might be useful for selecting new molecules with improved specificity and affinity toward the HIV-1 DIS RNA. PMID:17942426

  19. Ultrastructural analysis of aminoglycoside-induced hair cell death in the zebrafish lateral line reveals an early mitochondrial response.

    OpenAIRE

    Owens, Kelly,; Cunningham, Dale,; Macdonald, Glen; Rubel, Edwin,; Raible, David,; Pujol, Remy

    2007-01-01

    Loss of the mechanosensory hair cells in the auditory and vestibular organs leads to hearing and balance deficits. To investigate initial, in vivo events in aminoglycoside-induced hair cell damage, we examined hair cells from the lateral line of the zebrafish, Danio rerio. The mechanosensory lateral line is located externally on the animal and therefore allows direct manipulation and observation of hair cells. Labeling with vital dyes revealed a rapid response of hair cells to the aminoglycos...

  20. Purification, crystallization and preliminary X-ray analysis of Enterococcus casseliflavus aminoglycoside-2′′-phosphotransferase-IVa

    International Nuclear Information System (INIS)

    Aminoglycoside-2′′-phosphotransferase-IVa [APH(2′′)-IVa] is an enzyme that is responsible for high-level gentamicin resistance in E. casseliflavus isolates. Three different crystals of wild-type substrate-free APH(2′′)-IVa have been prepared and preliminary X-ray diffraction experiments have been undertaken on all three crystal forms. The deactivation of aminoglycoside antibiotics by chemical modification is one of the major sources of bacterial resistance to this family of therapeutic compounds, which includes the clinically relevant drugs streptomycin, kanamycin and gentamicin. The aminoglycoside phosphotransferases (APHs) form one such family of enzymes responsible for this resistance. The gene encoding one of these enzymes, aminoglycoside-2′′-phosphotransferase-IVa [APH(2′′)-IVa] from Enterococcus casseliflavus, has been cloned and the protein (comprising 306 amino-acid residues) has been expressed in Escherichia coli and purified. The enzyme was crystallized in three substrate-free forms. Two of the crystal forms belonged to the orthorhombic space group P212121 with similar unit-cell parameters, although one of the crystal forms had a unit-cell volume that was approximately 13% smaller than the other and a very low solvent content of around 38%. The third crystal form belonged to the monoclinic space group P21 and preliminary X-ray diffraction analysis was consistent with the presence of two molecules in the asymmetric unit. The orthorhombic crystal forms of apo APH(2′′)-IVa both diffracted to 2.2 Å resolution and the monoclinic crystal form diffracted to 2.4 Å resolution; synchrotron diffraction data were collected from these crystals at SSRL (Stanford, California, USA). Structure determination by molecular replacement using the structure of the related enzyme APH(2′′)-IIa is proceeding

  1. Resistance-Nodulation-Cell Division-Type Efflux Pump Involved in Aminoglycoside Resistance in Acinetobacter baumannii Strain BM4454

    OpenAIRE

    Magnet, Sophie; Courvalin, Patrice; Lambert, Thierry

    2001-01-01

    Multidrug-resistant strain Acinetobacter baumannii BM4454 was isolated from a patient with a urinary tract infection. The adeB gene, which encodes a resistance-nodulation-cell division (RND) protein, was detected in this strain by PCR with two degenerate oligodeoxynucleotides. Insertional inactivation of adeB in BM4454, which generated BM4454-1, showed that the corresponding protein was responsible for aminoglycoside resistance and was involved in the level of susceptibility to other drugs in...

  2. Appearance of amikacin and tobramycin resistance due to 4'-aminoglycoside nucleotidyltransferase [ANT(4')-II] in gram-negative pathogens.

    OpenAIRE

    Jacoby, G A; Blaser, M J; Santanam, P; Hächler, H; Kayser, F H; Hare, R S; Miller, G. H.

    1990-01-01

    Following the use of amikacin as the principal aminoglycoside at a Denver hospital, amikacin resistance appeared first in Pseudomonas aeruginosa and then in Escherichia coli, Klebsiella pneumoniae, and other enteric organisms from debilitated and compromised patients who had spent time in intensive care units and who had been treated with multiple antibiotics, usually including amikacin. In a P. aeruginosa isolate, resistance to amikacin and tobramycin was transferable by the IncP-2 plasmid p...

  3. Screen of FDA-approved drug library reveals compounds that protect hair cells from aminoglycosides and cisplatin

    OpenAIRE

    Vlasits, Anna L.; Simon, Julian A.; Raible, David W.; Rubel, Edwin W; Owens, Kelly N.

    2012-01-01

    Loss of mechanosensory hair cells in the inner ear accounts for many hearing loss and balance disorders. Several beneficial pharmaceutical drugs cause hair cell death as a side effect. These include aminoglycoside antibiotics, such as neomycin, kanamycin and gentamicin, and several cancer chemotherapy drugs, such as cisplatin. Discovering new compounds that protect mammalian hair cells from toxic insults is experimentally difficult because of the inaccessibility of the inner ear. We used the ...

  4. Prevalence of resistance to aminoglycosides and fluoroquinolones among Pseudomonas aeruginosa strains in a University Hospital in Northeastern Poland

    OpenAIRE

    Anna Diana Michalska; Pawel Tomasz Sacha; Dominika Ojdana; * Anna Wieczorek; Elzbieta Tryniszewska

    2014-01-01

    The present study was conducted to investigate the prevalence of genes encoding resistance to aminoglycosides and fluoroquinolones among twenty-five Pseudomonas aeruginosa isolated between 2002 and 2009. In PCR, following genes were detected: ant(2″)-Ia in 9 (36.0%), aac(6′)-Ib in 7 (28.0%), qnrB in 5 (20.0%), aph(3″)-Ib in 2 (8.0%) of isolates.

  5. In vitro read-through of phenylalanine hydroxylase (PAH) nonsense mutations using aminoglycosides: a potential therapy for phenylketonuria.

    Science.gov (United States)

    Ho, Gladys; Reichardt, Juergen; Christodoulou, John

    2013-11-01

    Phenylketonuria (PKU, OMIM 261600) is an autosomal recessive inborn error of phenylalanine metabolism, predominantly caused by mutations in the phenylalanine hydroxylase (PAH) gene. Approximately 10% of patients carry a nonsense mutation, which results in an inactive or unstable truncated protein. In some genetic disorders, including cystic fibrosis and Duchenne muscular dystrophy, restoration of full-length protein has been achieved by aminoglycoside antibiotics, such as gentamicin and G-418 (Geneticin). More recently, nonsense read-through has been induced at greater rates using a non-aminoglycoside drug, PTC124 (Ataluren), which has the advantage of being non-toxic in contrast to the antibiotics. The efficacy of read-through induced by three compounds, aminoglycosides G418 and gentamicin, and PTC124 were evaluated for four nonsense mutations of PAH in an in vitro expression system in two mammalian cell lines (COS-7 and HEK293). The production of full-length PAH was investigated using western blotting and the functionality confirmed by enzyme activity. Gentamicin and G-418 induced read-through of nonsense PAH mutations in HEK293 cells. The read-through product partially restored enzymatic activity, which was significantly less than that of wild-type, but comparable to a missense mutation of PAH associated with less severe forms of PKU. Treatment with PTC124 up to 100 μM did not result in full-length PAH polypeptide. Nonsense read-through drugs are a potential form of treatment for PKU, although the high dosage of aminoglycosides used is not appropriate in a clinical setting. In vitro studies with new non-toxic read-through agents as well as in vivo studies would also be essential to determine the extent of read-through required to restore normal phenylalanine levels. PMID:23532445

  6. The comparative effects of aminoglycoside antibiotics and muscle relaxants on electrical field stimulation response in rat bladder smooth muscle.

    Science.gov (United States)

    Min, Chang Ho; Min, Young Sil; Lee, Sang Joon; Sohn, Uy Dong

    2016-06-01

    It has been reported that several aminoglycoside antibiotics have a potential of prolonging the action of non-depolarizing muscle relaxants by drug interactions acting pre-synaptically to inhibit acetylcholine release, but antibiotics itself also have a strong effect on relaxing the smooth muscle. In this study, four antibiotics of aminoglycosides such as gentamicin, streptomycin, kanamycin and neomycin were compared with skeletal muscle relaxants baclofen, tubocurarine, pancuronium and succinylcholine, and a smooth muscle relaxant, papaverine. The muscle strips isolated from the rat bladder were stimulated with pulse trains of 40 V in amplitude and 10 s in duration, with pulse duration of 1 ms at the frequency of 1-8 Hz, at 1, 2, 4, 6, 8 Hz respectively. To test the effect of four antibiotics on bladder smooth muscle relaxation, each of them was treated cumulatively from 1 μM to 0.1 mM with an interval of 5 min. Among the four antibiotics, gentamicin and neomycin inhibited the EFS response. The skeletal muscle relaxants (baclofen, tubocurarine, pancuronium and succinylcholine) and inhibitory neurotransmitters (GABA and glycine) did not show any significant effect. However, papaverine, had a significant effect in the relaxation of the smooth muscle. It was suggested that the aminoglycoside antibiotics have inhibitory effect on the bladder smooth muscle. PMID:27260628

  7. Activation of PI3K signaling prevents aminoglycoside-induced hair cell death in the murine cochlea

    Directory of Open Access Journals (Sweden)

    Azadeh Jadali

    2016-06-01

    Full Text Available Loss of sensory hair cells of the inner ear due to aminoglycoside exposure is a major cause of hearing loss. Using an immortalized multipotent otic progenitor (iMOP cell line, specific signaling pathways that promote otic cell survival were identified. Of the signaling pathways identified, the PI3K pathway emerged as a strong candidate for promoting hair cell survival. In aging animals, components for active PI3K signaling are present but decrease in hair cells. In this study, we determined whether activated PI3K signaling in hair cells promotes survival. To activate PI3K signaling in hair cells, we used a small molecule inhibitor of PTEN or genetically ablated PTEN using a conditional knockout animal. Hair cell survival was challenged by addition of gentamicin to cochlear cultures. Hair cells with activated PI3K signaling were more resistant to aminoglycoside-induced hair cell death. These results indicate that increased PI3K signaling in hair cells promote survival and the PI3K signaling pathway is a target for preventing aminoglycoside-induced hearing loss.

  8. The prevalence of aminoglycoside-modifying enzyme genes (aac (6′)-I, aac (6′)-II, ant (2″)-I, aph (3′)-VI) in Pseudomonas aeruginosa

    OpenAIRE

    Farzam Vaziri; Shahin Najar Peerayeh; Qorban Behzadian Nejad; Abbas Farhadian

    2011-01-01

    INTRODUCTION: Pseudomonas aeruginosa (P. aeruginosa) is one of the primary opportunistic pathogens responsible for nosocomial infections. Aminoglycosides are an import ant component of antipseudomonal chemotherapy. The inactivation of drugs by modifying enzymes is the most common mechanism of aminoglycoside resistance. OBJECTIVES: The inactivation of aminoglycosides by modifying enzymes is the primary resistance mechanism employed by P. aeruginosa. The aim of the present study was to investig...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-06-17

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-05-21

    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.

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

    International Nuclear Information System (INIS)

    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

  12. Study of the Interference between Plectranthus Species Essential Oils from Brazil and Aminoglycosides

    Directory of Open Access Journals (Sweden)

    Fabíola Fernandes Galvão Rodrigues

    2013-01-01

    Full Text Available Plectranthus is one of the most representative genera of Lamiaceae family. In this study, the essential oils from Plectranthus amboinicus, Plectranthus ornatus, and Plectranthus barbatus were investigated for their chemical composition and antimicrobial and modulatory activities. The major components found were carvacrol (54.4%—P. amboinicus and eugenol (22.9%—P. ornatus e 25.1%—P. barbatus. In vitro antimicrobial activity was conducted against Escherichia coli, Proteus vulgaris, Bacillus cereus, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus aureus (multiresistant using microdilution method. The results of bioassay showed that all strains were sensitive to the oils, except P. aeruginosa that was resistant to P. amboinicus and P. ornatus. A synergistic effect of all essential oils combined with the aminoglycosides was demonstrated. These results show that P. amboinicus, P. ornatus, and P. barbatus inhibit the growth of pathogenic microorganism, and besides this they present antibiotic modifying activity, providing a new perspective against the problem of bacterial resistance to antibiotics.

  13. Andrographolide: A potent antituberculosis compound that targets Aminoglycoside 2'-N-acetyltransferase in Mycobacterium tuberculosis.

    Science.gov (United States)

    Prabu, Amudha; Hassan, Sameer; Prabuseenivasan; Shainaba, A S; Hanna, L E; Kumar, Vanaja

    2015-09-01

    Tuberculosis (TB) still remains a major challenging infectious disease. The increased rate of emergence of multi-drug resistant and extensively-drug resistant strains of the organism has further complicated the situation, resulting in an urgent need for new anti-TB drugs. Antimycobacterial activity of Andrographis paniculata was evaluated using a rapid LRP assay and the probable targets were identified by docking analysis. The methanolic extract of A. paniculata showed maximum antimycobacterial activity at 250μg/ml against all the tested strains of M. tuberculosis (H37Rv, MDR, and drug sensitive). Based on bioassay guided fractionation, andrographolide was identified as the potent molecule. With the docking analysis, both ICDH (Isocitrate Dehydrogenase) and AAC (Aminoglycoside 2'-N-acetyltransferase) were predicted as targets of andrographolide in M. tuberculosis. Molecular simulation revealed that, ICDH showed low binding affinity to andrographolide. However, for AAC, the andrographolide was observed to be well within the active site after 10ns of molecular simulation. This suggests that ACC (PDB ID 1M4I) could be the probable target for andrographolide. PMID:26245695

  14. Effects of salicylates and aminoglycosides on spontaneous otoacoustic emissions in the Tokay gecko.

    Science.gov (United States)

    Stewart, C E; Hudspeth, A J

    2000-01-01

    The high sensitivity and sharp frequency discrimination of hearing depend on mechanical amplification in the cochlea. To explore the basis of this active process, we examined the pharmacological sensitivity of spontaneous otoacoustic emissions (SOAEs) in a lizard, the Tokay gecko. In a quiet environment, each ear produced a complex but stable pattern of emissions. These SOAEs were reversibly modulated by drugs that affect mammalian otoacoustic emissions, the salicylates and the aminoglycoside antibiotics. The effect of a single i.p. injection of sodium salicylate depended on the initial power of the emissions: ears with strong control SOAEs displayed suppression at all frequencies, whereas those with weak control emissions showed enhancement. Repeated oral administration of acetylsalicylic acid reduced all emissions. Single i.p. doses of gentamicin or kanamycin suppressed SOAEs below 2.6 kHz, while modulating those above 2.6 kHz in either of two ways. For ears whose emission power at 2.6-5.2 kHz encompassed more than half of the total, individual emissions displayed facilitation as great as 35-fold. For the remaining ears, emissions dropped to as little as one-sixth of their initial values. The similarity of the responses of reptilian and mammalian cochleas to pharmacological intervention provides further evidence for a common mechanism of cochlear amplification. PMID:10618439

  15. Hair cell regeneration in the bullfrog vestibular otolith organs following aminoglycoside toxicity

    Science.gov (United States)

    Baird, Richard A.; Torres, M. A.; Schuff, N. R.

    1994-01-01

    Adult bullfrogs were given single intraotic injections of the aminoglycoside antibiotic gentamicin sulfate and sacrificed at postinjection times ranging from 0.5 to 9 days. The saccular and utricular maculae of normal and injected animals were examined in wholemount and cross-section. Intraotic 200 (mu) M gentamicin concentrations resulted in the uniform destruction of the hair bundles and, at later times, the cell bodies of saccular hair cells. In the utriculus, striolar hair cells were selectively damaged while extrastriolar hair cells were relatively unaffected. Regenerating hair cells, identified in sectioned material by their small cell bodies and short, well-formed hair bundles, were seen in the saccular and utricular maculae as early as 24-48 h postinjection. Immature versions of mature hair cell types in both otolith organs were recognized by the presence of absence of a bulbed kinocilia and the relative lengths of their kinocilia and longest sterocilia. Utricular hair cell types with kinocilia longer than their longest stereocilia were observed at earlier times than hair cell types with shorter kinocilia. In the same sacculus, the hair bundles of gentamicin-treated animals, even at 9 days postinjection, were significantly smaller than those of normal animals. The hair bundles of utricular hair cells, on the other hand, reached full maturity within the same time period.

  16. 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.

  17. Introducing Aztreonam The First Monobactam Antibiotic, A Suitable Substitution for the Aminoglycosides

    Directory of Open Access Journals (Sweden)

    A. Jahanshahi M.Khajeh - Karamadeni S. Fazli Bazaz

    1992-07-01

    Full Text Available Aztreonam (Azactam for injection, squibb is the first member of a new and unique class of beta - lactam antibiotics designated by researchers at the Squibb Institute for Medical Research as monobactams (monocyclic bacterially produced beta - lactam antibiotics."nIn this research, for the first time, antimicrobial spectrum of aztrenoam was determined by Disk - Agar Diffusion (250 spp. and Macrodilution Broth Methods (150 Spp."nWe also compared this antibiotic with two routine aminoglycoside antibiotics (Amikacin, Gentamicin in Iran. The most active antibiotic in our study was aztreonam which had MIC50 & MIC90 of 4 & 32 ^g/ml specifically against Pseudomonas aeruginosa."nThis rate for the other aerobic gram - negative bacteria (E. coli, Kleb. pneumoniae, Proteus mirabilis, enterobacter spp., Shigella Spp. and Salmonella Spp. was less than 0.5 & 4 g/ml respectively."nAztreonam's MIC90 for kleb pneumoniae was 8/jg/mI our results were Correlated to the other studies"nAll aerobic gram - negative bacteria has been obtained from the Qhaem's Medical Center in Mashhad - IRAN."nThe results of Disk - Agar Diffusion Method determines that all bacteria were 100% susceptible against aztreonam except Pseudomonas aeruginosa with 83% susceptibility.

  18. Highly stable, protein capped gold nanoparticles as effective drug delivery vehicles for amino-glycosidic antibiotics

    International Nuclear Information System (INIS)

    A method for the production of highly stable gold nanoparticles (Au NP) was optimized using sodium borohydride as reducing agent and bovine serum albumin as capping agent. The synthesized nanoparticles were characterized using UV–visible spectroscopy, transmission electron microscopy, X‐ray diffraction (XRD) and dynamic light scattering techniques. The formation of gold nanoparticles was confirmed from the appearance of pink colour and an absorption maximum at 532 nm. These protein capped nanoparticles exhibited excellent stability towards pH modification and electrolyte addition. The produced nanoparticles were found to be spherical in shape, nearly monodispersed and with an average particle size of 7.8 ± 1.7 nm. Crystalline nature of the nanoparticles in face centered cubic structure is confirmed from the selected‐area electron diffraction and XRD patterns. The nanoparticles were functionalized with various amino-glycosidic antibiotics for utilizing them as drug delivery vehicles. Using Fourier transform infrared spectroscopy, the possible functional groups of antibiotics bound to the nanoparticle surface have been examined. These drug loaded nanoparticle solutions were tested for their antibacterial activity against Gram-negative and Gram-positive bacterial strains, by well diffusion assay. The antibiotic conjugated Au NP exhibited enhanced antibacterial activity, compared to pure antibiotic at the same concentration. Being protein capped and highly stable, these gold nanoparticles can act as effective carriers for drugs and might have considerable applications in the field of infection prevention and therapeutics. - Highlights: ► Method for NaBH4 reduced and BSA capped gold nanoparticle was standardized. ► Nanoparticles were spherical and nearly monodispersed with a size of 7.8 nm. ► Nanoparticles are extremely stable towards pH modification and electrolyte addition. ► Antibiotic conjugated nanoparticles exhibited enhanced antibacterial activity

  19. 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. PMID:27033000

  20. Characterization of a C3 Deoxygenation Pathway Reveals a Key Branch Point in Aminoglycoside Biosynthesis.

    Science.gov (United States)

    Lv, Meinan; Ji, Xinjian; Zhao, Junfeng; Li, Yongzhen; Zhang, Chen; Su, Li; Ding, Wei; Deng, Zixin; Yu, Yi; Zhang, Qi

    2016-05-25

    Apramycin is a clinically interesting aminoglycoside antibiotic (AGA) containing a highly unique bicyclic octose moiety, and this octose is deoxygenated at the C3 position. Although the biosynthetic pathways for most 2-deoxystreptamine-containing AGAs have been well characterized, the pathway for apramycin biosynthesis, including the C3 deoxygenation process, has long remained unknown. Here we report detailed investigation of apramycin biosynthesis by a series of genetic, biochemical and bioinformatical studies. We show that AprD4 is a novel radical S-adenosyl-l-methionine (SAM) enzyme, which uses a noncanonical CX3CX3C motif for binding of a [4Fe-4S] cluster and catalyzes the dehydration of paromamine, a pseudodisaccharide intermediate in apramycin biosynthesis. We also show that AprD3 is an NADPH-dependent reductase that catalyzes the reduction of the dehydrated product from AprD4-catalyzed reaction to generate lividamine, a C3' deoxygenated product of paromamine. AprD4 and AprD3 do not form a tight catalytic complex, as shown by protein complex immunoprecipitation and other assays. The AprD4/AprD3 enzyme system acts on different pseudodisaccharide substrates but does not catalyze the deoxygenation of oxyapramycin, an apramycin analogue containing a C3 hydroxyl group on the octose moiety, suggesting that oxyapramycin and apramycin are partitioned into two parallel pathways at an early biosynthetic stage. Functional dissection of the C6 dehydrogenase AprQ shows the crosstalk between different AGA biosynthetic gene clusters from the apramycin producer Streptomyces tenebrarius, and reveals the remarkable catalytic versatility of AprQ. Our study highlights the intriguing chemistry in apramycin biosynthesis and nature's ingenuity in combinatorial biosynthesis of natural products. PMID:27120352

  1. Efficacy of an ototoxic aminoglycoside (gentamicin) on the differentiation of the inner ear of cichlid fish

    Science.gov (United States)

    Schönleber, J.; Anken, R. H.

    2004-01-01

    Previous investigations revealed that the growth of fish inner ear otoliths depends on the amplitude and the direction of gravity, thus suggesting the existence of a (negative) feedback mechanism. In the course of these experiments, it was shown that altered gravity both affected otolith size (and thus the provision of the proteinacious matrix) as well as the incorporation of calcium. It is hitherto unknown, as of whether sensory hair cells are involved either in the regulation of otolith growth or in the provision of otolithic material (such as protein or inorganic components) or even both. The ototoxic aminoglycoside gentamicin (GM) damages hair cells in many vertebrates (and is therefore used for the treatment of Meniere's disease in humans). The present study was thus designed to determine as of whether vestibular sensory cells are needed for otolith growth by applying GM in order to induce a (functionally relevant) loss of these cells. Developing cichlid fish Oreochromis mossambicus were therefore immersed in 120 mg/l GM for 10 or 21 days. At the beginning and at the end of the experimental periods, the fish were incubated in the calcium-tracer alizarin complexone (AC). After the experiment, otoliths were dissected and the area grown during GM-exposure (i.e., the area enclosed by the two AC labellings) was determined planimetrically. The results showed that incubating the animals in a GM-solution had no effect on otolith growth, but the development of otolith asymmetry was affected. Ultrastructural examinations of the sensory hair cells revealed that they had obviously not been affected by GM-treatment (no degenerative morphological features observed). Overall, the present results suggest that hair cells are not affected by GM concerning their possible role in (general) otolith growth, but that these cells indeed might have transitionally been impaired by GM resulting in a decreased capacity of regulating otolith symmetry.

  2. SYNTHESIS AND CYTOTOXIC ACTIVITY OF NEW 5H-INDOLO[2,3-B]QUINOLINE O-AMINOGLYCOSIDES.

    Science.gov (United States)

    Badowska-Rosłonek, Katarzyna; Ciesielska, Agnieszka; Switalska, Marta; Piskozub, Małgorzata; Peczyńska-Czoch, Wanda; Wietrzyk, Joanna; Kaczmarek, Łukasz

    2016-01-01

    Novel 5H-indolo[2,3-b]quinoline O-aminoglycosides were synthesized in order to check the hypothesis that the construction of hybrids composed of the active 5H-indolo[2,3-b]quinoline chromophore and daunosaminyl or acosaminyl moiety may result in the cytotoxic activity of the obtained derivatives that is much higher than the one of the parent DIMIQ (5,11-dimethyl-5H-indolo[2,3-b]quinoline) and 6H-indoloquinoline analogs. Actually, 5H-indolo[2,3-b]indoloquinoline O-aminoglycosides showed the anti-proliferative activity in vitro against human lung adenocarcinoma A549, breast cancer MCF-7, melanoma Hs294T, promyelocytic leukemia HL-60, uterine sarcoma MES-SA and colon cancer LoVo cell lines, which was 10 times higher than that of the 6H-analogs and comparable to the one of the referential DIMIQ. Unexpectedly, it appeared that except for HL-60/MX2 (P-gp-independent and topoisomerase II-dependent resistance), other MDR tumor cell lines (LoVo/DX. P-gp-dependent, MRP-, LRP-dependent multidrug resistance) and MES-SA/DX5 (P-gp-dependent resistance to doxorubicin) are also resistant to the 5H-indolo[2,3-b]indoloquinoline O-aminoglycosides tested. This is surprising because 6H-analogs, in general, 10 times less active against non-MDR tumor cell lines, as well as the DIMIQ itself, are able to overcome drug resistance in all MDR cell lines examined. The cytotoxicity of the tested compounds against tumor cell lines and against normal cells (mice fibroblasts BALB/3T3) was comparable. PMID:27476287

  3. Natural antioxidant L-carnosine inhibits LPO intensification in structures of the auditory analyzer under conditions of chronic exposure to aminoglycoside antibiotics.

    Science.gov (United States)

    Zhuravskii, S G; Aleksandrova, L A; Sirot, V S; Ivanov, S A

    2004-10-01

    Intragastric administration of L-carnosine suspension to Wistar-Kyoto rats 3 days before and after 7-day course of intraperitoneal injections of ototoxic aminoglycoside antibiotic kanamycin compensated expenditures of tissue antioxidant systems and significantly eliminated kanamycin-induced intensification of MDA production in tissues of the membrane part of the cochlea and in the auditory cortex of the temporal lobe. L-NAME (competitive NO synthase inhibitor) also inhibited LPO, increased total antioxidant activity, and decreased ototoxicity of kanamycin, which confirms the contribution of NO into LPO intensification under conditions of aminoglycoside treatment. Inhibition of pathological intensification of LPO processes and increase in total antioxidant activity under conditions of induced acute aminoglycoside ototoxicity characterizes L-carnosine as a highly effective otoprotector. PMID:15665945

  4. Plasmid-Mediated High-Level Resistance to Aminoglycosides in Enterobacteriaceae Due to 16S rRNA Methylation

    OpenAIRE

    Galimand, Marc; Courvalin, Patrice; Lambert, Thierry

    2003-01-01

    A self-transferable plasmid of ca. 80 kb, pIP1204, conferred multiple-antibiotic resistance to Klebsiella pneumoniae BM4536, which was isolated from a urinary tract infection. Resistance to β-lactams was due to the blaTEM1 and blaCTX-M genes, resistance to trimethroprim was due to the dhfrXII gene, resistance to sulfonamides was due to the sul1 gene, resistance to streptomycin-spectinomycin was due to the ant3"9 gene, and resistance to nearly all remaining aminoglycosides was due to the aac3-...

  5. Early transcriptional response to aminoglycoside antibiotic suggests alternate pathways leading to apoptosis of sensory hair cells in the mouse inner ear

    Directory of Open Access Journals (Sweden)

    Neil eSegil

    2015-05-01

    Full Text Available Aminoglycoside antibiotics are the drug of choice for treating many bacterial infections, but their administration results in hearing loss in nearly one fourth of the patients who receive them. Several biochemical pathways have been implicated in aminoglycoside antibiotic ototoxicity; however, little is known about how hair cells respond to aminoglycoside antibiotics at the transcriptome level. Here we have investigated the genome-wide response to the aminoglycoside antibiotic gentamicin. Using organotypic cultures of the perinatal organ of Corti, we performed RNA sequencing using cDNA libraries obtained from FACS-purified hair cells. Within 3 hours of gentamicin treatment, the messenger RNA level of more than three thousand genes in hair cells changed significantly. Bioinformatic analysis of these changes highlighted several known signal transduction pathways, including the JNK pathway and the NF-κB pathway, in addition to genes involved in the stress response, apoptosis, cell cycle control, and DNA damage repair. In contrast, only 698 genes, mainly involved in cell cycle and metabolite biosynthetic processes, were significantly affected in the non-hair cell population. The gene expression profiles of hair cells in response to gentamicin share a considerable similarity with those previously observed in gentamicin-induced nephrotoxicity. Our findings suggest that previously observed early responses to gentamicin in hair cells in specific signaling pathways are reflected in changes in gene expression. Additionally, the observed changes in gene expression of cell cycle regulatory genes indicate a disruption of the postmitotic state, which may suggest an alternative pathway regulating gentamicin-induced hair cell death. This work provides a more comprehensive view of aminoglycoside antibiotic ototoxicity, and thus contribute to identifying potential pathways or therapeutic targets to alleviate this important side effect of aminoglycoside

  6. COMBINATIONAL ADMINISTRATION OF AMINOGLYCOSIDES AND LOOP DIURETICS AS AN EFFICIENT STRATEGY TO ESTABLISH DEAFNESS MODELS IN RATS

    Institute of Scientific and Technical Information of China (English)

    CONG Tao; LIU Riyuan; YUAN Shuolong; XU Liangwei; YANG Shiming

    2014-01-01

    It is known that aminoglycoside antibiotics can damage the vestibular and auditory sensory epithelia, and the loop diuretics can enhance the ototoxic effect of aminoglycosides. Previous studies on the synergistic effect of these two types of drugs have used mice, guinea pigs and cats, but not rats. The aim of this study was to determine this synergistic effects in rat cochleae. Rats received intravenous injections of different doses of furosemide and/or intramuscular injections of kanamycin sulfate. Au-ditory brainstem response (ABR), scanning electron microscopy (SEM) and immunocytochemistry were used to determine the effects of drug administration. In the group receiving combined administration of furosemide and kanamycin, the ABR thresh-old showed significant elevation 3 days after drug administration, greater than single drug administration. The hair cells showed various degrees of injury from the apical turn to the basal turn of the cochlea and from the outer hair cells to the inner hair cells. Neuron fibers of the hair cells showed significant loss 7 days after the drug administration, but the number of spiral ganglia did not decrease and supporting cells showed no signs of injury. Our study suggest that combined administration of fu-rosemide and kanamycin has an synergistic ototoxic effect, and can result in hair cell loss and hearing loss in rats.

  7. Directed evolution of aminoglycoside phosphotransferase (3' type IIIa variants that inactivate amikacin but impose significant fitness costs.

    Directory of Open Access Journals (Sweden)

    Joseph R Kramer

    Full Text Available The rules that govern adaptive protein evolution remain incompletely understood. Aminoglycoside aminotransferase (3' type IIIa (hereafter abbreviated APH(3'-IIIa is a good model enzyme because it inactivates kanamycin efficiently; it recognizes other aminoglycoside antibiotics, including amikacin, but not nearly as well. Here we direct the evolution of APH(3'-IIIa variants with increased activity against amikacin. After four rounds of random mutation and selection in Escherichia coli, the minimum inhibitory concentration of amikacin rose from 18 micrograms/mL (wild-type enzyme to over 1200 micrograms/mL (clone 4.1. The artificially evolved 4.1 APH(3'-IIIa variant exhibited 19-fold greater catalytic efficiency (k cat/K M than did the wild-type enzyme in reactions with amikacin. E. coli expressing the evolved 4.1 APH(3'-IIIa also exhibited a four-fold decrease in fitness (as measured by counting colony forming units in liquid cultures with the same optical density compared with isogenic cells expressing the wild-type protein under non-selective conditions. We speculate that these fitness costs, in combination with the prevalence of other amikacin-modifying enzymes, hinder the evolution of APH(3'-IIIa in clinical settings.

  8. A preliminary report on the susceptibility to aminoglycosides of Escherichia coli isolated from the community-acquired urinary tract infections in adults in south-east Poland

    Directory of Open Access Journals (Sweden)

    Fidecka-Skwarzynska Magdalena

    2015-03-01

    Full Text Available World-wide, urinary tract infections (UTIs are an important clinical problem. In such, the most frequently isolated uropathogen is Escherichia coli. In the treatment of uncomplicated UTIs, e.g. cystitis, the widely used antibiotics are nitrofurantoin, trimethoprim/sulfamethoxazole, fosfomycin trometamol or ciprofloxacin, while the treatment of pyelonephritis requires the usage of antibiotics with a broader spectrum of activity, such as cephalosporins of the 3rd and 4th generation, aminoglycosides or even carbapenems. The aim of this study was to assess the susceptibility to aminoglycosides (such as amikacin, gentamicin, netilmicin and tobramycin of E. coli isolated from UTIs in adult community patients living in Lubelszczyzna. We found that all of the 86 strains of E. coli encountered were susceptible to amikacin. Moreover, the prevalence of susceptibility to tobramycin, gentamicin or netilmicin among the tested strains was found to be 89,5%, 90,7% or 94,2%, respectively. The data obtained in the present study shows the high susceptibility to aminoglycosides of E. coli isolated from the community-acquired UTIS in adults. These data, together with that derived from current literature, indicate that aminoglycosides, when employed in combination therapy with other antibiotics, may still be very useful group of antibacterial agents in the treatment of UTI’s in Poland.

  9. Clinical evaluation and mitochondrial DNA sequence analysis in two Chinese families with aminoglycoside-induced and non-syndromic hearing loss

    International Nuclear Information System (INIS)

    We report here the clinical, genetic, and molecular characterization of two Chinese pedigrees with aminoglycoside-induced and non-syndromic hearing impairment. Clinical evaluation revealed the variable phenotype of hearing impairment including audiometric configuration in these subjects. Penetrances of hearing loss in BJ105 and BJ106 pedigrees are 67% and 33%, respectively. In particular, three of 10 affected matrilineal relatives of BJ105 pedigree had aminoglycoside-induced hearing loss, while seven affected matrilineal relatives in BJ105 pedigree and six affected matrilineal relatives in BJ106 pedigree did not have a history of exposure to aminoglycosides. Sequence analysis of the complete mitochondrial genomes in these pedigrees showed the identical homoplasmic A1555G mutation and distinct sets of mtDNA variants belonging to haplogroups F3 and M7b. These variants showed no evolutionary conservation, implying that mitochondrial haplotype may not play a significant role in the phenotypic expression of the A1555G mutation in these Chinese pedigrees. However, aminoglycosides and nuclear backgrounds appear to be major modifier factors for the phenotypic manifestation of the A1555G mutation in these Chinese families

  10. Association of the novel aminoglycoside resistance determinant RmtF with NDM carbapenemase in Enterobacteriaceae isolated in India and the UK

    DEFF Research Database (Denmark)

    Hidalgo, Laura; Hopkins, Katie L; Gutierrez, Belen; Ovejero, Cristina M; Shukla, Suruchi; Douthwaite, Stephen Roger; Prasad, Kashi N; Woodford, Neil; Gonzalez-Zorn, Bruno

    2013-01-01

    16S rRNA methyltransferases are an emerging mechanism conferring high-level resistance to clinically relevant aminoglycosides and have been associated with important mechanisms such as NDM-1. We sought genes encoding these enzymes in isolates highly resistant (MIC >200 mg/L) to gentamicin and ami...

  11. Mitochondrial 12S Ribosomal RNA A1555G Mutation Associated with Cardiomyopathy and Hearing Loss following High-Dose Chemotherapy and Repeated Aminoglycoside Exposure

    DEFF Research Database (Denmark)

    Skou, Anne-Sofie; Tranebjærg, Lisbeth; Jensen, Tim;

    2014-01-01

    A 19-month-old girl with the A1555G mitochondrial mutation in the 12S ribosomal RNA gene and acute myelogenous leukemia developed dilated cardiomyopathy and bilateral sensorineural hearing loss before undergoing allogeneic stem cell transplantation. She had received gentamicin during episodes of ...... febrile neutropenia. Testing for the A1555G mutation is recommended in patients frequently treated with aminoglycosides....

  12. 30S Subunit-Dependent Activation of the Sorangium cellulosum So ce56 Aminoglycoside Resistance-Conferring 16S rRNA Methyltransferase Kmr

    Science.gov (United States)

    Savic, Miloje; Sunita, S.; Zelinskaya, Natalia; Desai, Pooja M.; Macmaster, Rachel; Vinal, Kellie

    2015-01-01

    Methylation of bacterial 16S rRNA within the ribosomal decoding center confers exceptionally high resistance to aminoglycoside antibiotics. This resistance mechanism is exploited by aminoglycoside producers for self-protection while functionally equivalent methyltransferases have been acquired by human and animal pathogenic bacteria. Here, we report structural and functional analyses of the Sorangium cellulosum So ce56 aminoglycoside resistance-conferring methyltransferase Kmr. Our results demonstrate that Kmr is a 16S rRNA methyltransferase acting at residue A1408 to confer a canonical aminoglycoside resistance spectrum in Escherichia coli. Kmr possesses a class I methyltransferase core fold but with dramatic differences in the regions which augment this structure to confer substrate specificity in functionally related enzymes. Most strikingly, the region linking core β-strands 6 and 7, which forms part of the S-adenosyl-l-methionine (SAM) binding pocket and contributes to base flipping by the m1A1408 methyltransferase NpmA, is disordered in Kmr, correlating with an exceptionally weak affinity for SAM. Kmr is unexpectedly insensitive to substitutions of residues critical for activity of other 16S rRNA (A1408) methyltransferases and also to the effects of by-product inhibition by S-adenosylhomocysteine (SAH). Collectively, our results indicate that adoption of a catalytically competent Kmr conformation and binding of the obligatory cosubstrate SAM must be induced by interaction with the 30S subunit substrate. PMID:25733511

  13. Study of matrix effects for liquid chromatography-electrospray ionization tandem mass spectrometric analysis of 4 aminoglycosides residues in milk.

    Science.gov (United States)

    Wang, Yuan; Li, Shaohui; Zhang, Feifang; Lu, Yifeng; Yang, Bingcheng; Zhang, Feng; Liang, Xinmiao

    2016-03-11

    Matrix effect (ME) is always a major issue for the development of LC-MS/MS method. ME resulting from co-eluting residual matrix components can affect the ionization efficiency of target analytes, leading to quantification errors of the analytes of interest. The present work evaluates MEs of milk samples on simultaneous analysis of four aminoglycosides residues via LC-ESI/MS/MS including streptomycin, dihydrostreptomycin, spectinomycin and kanamycin. Approaches to reduce MEs were examined: optimization of the sample preparation, sample dilution and lower flow rate used. Three commercial sorbents were tested including Oasis MCX, Oasis HLB and Oasis WCX. WCX behaved better for all analytes, but high MEs (80.8-134.9%) were obtained. Therefore, a consecutive SPE of tC18-WCX was found to effectively reduce ME. Milk samples from different manufacturers were analyzed and low MEs (85.6-112.9%) were obtained. PMID:26875117

  14. Development of aminoglycoside and β-lactamase resistance in intestinal microbiota of swine treated with lincomycin, chlorotetracycline and amoxicillin

    Directory of Open Access Journals (Sweden)

    Jian eSun

    2014-11-01

    Full Text Available Lincomycin, chlortetracycline, and amoxicillin are commonly used antimicrobials for growth promotion and infectious disease prophylaxis in swine production. In this study, we investigated the shifts and resistance development among intestinal microbiota in pregnant sows before and after lincomycin, chlortetracycline, and amoxicillin treatment by using phylogenetic analysis, bacterial enumeration, and PCR. After the antimicrobial treatment, shifts in microbial community, an increased proportion of resistant bacteria, and genes related to antimicrobial resistance as compared to the day before antimicrobial administration (day 0 were observed. Importantly, a positive correlation between antimicrobial resistance gene expression in different categories, especially those encoding aminoglycoside and β-lactamase and antimicrobial resistance, was observed. These findings demonstrate an important role of antimicrobial usage in animals in the development of antimicrobial resistance, and support the notion that prudent use of antimicrobials in swine is needed to reduce the risk of the emergence of multi-drug resistant (MDR zoonotic pathogens.

  15. Effect of mutations in the A site of 16 S rRNA on aminoglycoside antibiotic-ribosome interaction

    DEFF Research Database (Denmark)

    Recht, M I; Douthwaite, S; Dahlquist, K D;

    1999-01-01

    Decoding of genetic information occurs upon interaction of an mRNA codon-tRNA anticodon complex with the small subunit of the ribosome. The ribosomal decoding region is associated with highly conserved sequences near the 3' end of 16 S rRNA. The decoding process is perturbed by the aminoglycoside...... of universally conserved nucleotides at 1406 to 1408 and 1494 to 1495 in the decoding region of plasmid-encoded bacterial 16 S rRNA. Phenotypic changes range from the benign effect of U1406-->A or A1408-->G substitutions, to the highly deleterious 1406G and 1495 mutations that assemble into 30 S subunits...... but are defective in forming functional ribosomes. Changes in the local conformation of the decoding region caused by these mutations were identified by chemical probing of isolated 30 S subunits. Ribosomes containing 16 S rRNA with mutations at positions 1408, 1407+1494, or 1495 had reduced affinity...

  16. Involvement of aph(3‘-IIa in the formation of mosaic aminoglycoside resistance genes in natural environments

    Directory of Open Access Journals (Sweden)

    Markus eWoegerbauer

    2015-05-01

    Full Text Available Intragenic recombination leading to mosaic gene formation is known to alter resistance profiles for particular genes and bacterial species. Few studies have examined to what extent aminoglycoside resistance genes undergo intragenic recombination.We screened the GenBank database for mosaic gene formation in homologs of the aph(3’-IIa (nptII gene. APH(3’-IIa inactivates important aminoglycoside antibiotics. The gene is widely used as a selectable marker in biotechnology and enters the environment via laboratory discharges and the release of transgenic organisms. Such releases may provide opportunities for recombination in competent environmental bacteria.The retrieved GenBank sequences were grouped in 3 datasets comprising river water samples, duck pathogens and full-length variants from various bacterial genomes and plasmids. Analysis for recombination in these datasets was performed with the Recombination Detection Program, RDP4, and the Genetic Algorithm for Recombination Detection, GARD.From a total of 89 homologous sequences, 83% showed 99% - 100% sequence identity with aph(3’-IIa originally described as part of transposon Tn5. Fifty one were unique sequence variants eligible for recombination analysis. Only a single recombination event was identified with high confidence and indicated the involvement of aph(3’-IIa in the formation of a mosaic gene located on a plasmid of environmental origin in the multi-resistant isolate Pseudomonas aeruginosa PA96. The available data suggest that aph(3’-IIa is not an archetypical mosaic gene as the divergence between the described sequence variants and the number of detectable recombination events is low. This is in contrast to the numerous mosaic alleles reported for certain penicillin or tetracycline resistance determinants.

  17. Involvement of aph(3′)-IIa in the formation of mosaic aminoglycoside resistance genes in natural environments

    Science.gov (United States)

    Woegerbauer, Markus; Kuffner, Melanie; Domingues, Sara; Nielsen, Kaare M.

    2015-01-01

    Intragenic recombination leading to mosaic gene formation is known to alter resistance profiles for particular genes and bacterial species. Few studies have examined to what extent aminoglycoside resistance genes undergo intragenic recombination. We screened the GenBank database for mosaic gene formation in homologs of the aph(3′)-IIa (nptII) gene. APH(3′)-IIa inactivates important aminoglycoside antibiotics. The gene is widely used as a selectable marker in biotechnology and enters the environment via laboratory discharges and the release of transgenic organisms. Such releases may provide opportunities for recombination in competent environmental bacteria. The retrieved GenBank sequences were grouped in three datasets comprising river water samples, duck pathogens and full-length variants from various bacterial genomes and plasmids. Analysis for recombination in these datasets was performed with the Recombination Detection Program (RDP4), and the Genetic Algorithm for Recombination Detection (GARD). From a total of 89 homologous sequences, 83% showed 99–100% sequence identity with aph(3′)-IIa originally described as part of transposon Tn5. Fifty one were unique sequence variants eligible for recombination analysis. Only a single recombination event was identified with high confidence and indicated the involvement of aph(3′)-IIa in the formation of a mosaic gene located on a plasmid of environmental origin in the multi-resistant isolate Pseudomonas aeruginosa PA96. The available data suggest that aph(3′)-IIa is not an archetypical mosaic gene as the divergence between the described sequence variants and the number of detectable recombination events is low. This is in contrast to the numerous mosaic alleles reported for certain penicillin or tetracycline resistance determinants. PMID:26042098

  18. The MisR Response Regulator Is Necessary for Intrinsic Cationic Antimicrobial Peptide and Aminoglycoside Resistance in Neisseria gonorrhoeae.

    Science.gov (United States)

    Kandler, Justin L; Holley, Concerta L; Reimche, Jennifer L; Dhulipala, Vijaya; Balthazar, Jacqueline T; Muszyński, Artur; Carlson, Russell W; Shafer, William M

    2016-08-01

    During infection, the sexually transmitted pathogen Neisseria gonorrhoeae (the gonococcus) encounters numerous host-derived antimicrobials, including cationic antimicrobial peptides (CAMPs) produced by epithelial and phagocytic cells. CAMPs have both direct and indirect killing mechanisms and help link the innate and adaptive immune responses during infection. Gonococcal CAMP resistance is likely important for avoidance of host nonoxidative killing systems expressed by polymorphonuclear granulocytes (e.g., neutrophils) and intracellular survival. Previously studied gonococcal CAMP resistance mechanisms include modification of lipid A with phosphoethanolamine by LptA and export of CAMPs by the MtrCDE efflux pump. In the related pathogen Neisseria meningitidis, a two-component regulatory system (2CRS) termed MisR-MisS has been shown to contribute to the capacity of the meningococcus to resist CAMP killing. We report that the gonococcal MisR response regulator but not the MisS sensor kinase is involved in constitutive and inducible CAMP resistance and is also required for intrinsic low-level resistance to aminoglycosides. The 4- to 8-fold increased susceptibility of misR-deficient gonococci to CAMPs and aminoglycosides was independent of phosphoethanolamine decoration of lipid A and the levels of the MtrCDE efflux pump and seemed to correlate with a general increase in membrane permeability. Transcriptional profiling and biochemical studies confirmed that expression of lptA and mtrCDE was not impacted by the loss of MisR. However, several genes encoding proteins involved in membrane integrity and redox control gave evidence of being MisR regulated. We propose that MisR modulates the levels of gonococcal susceptibility to antimicrobials by influencing the expression of genes involved in determining membrane integrity. PMID:27216061

  19. Mechanistic studies of copper(II)-aminoglycoside mediated DNA damage and magnesium catalyzed nuclease activity of hammerhead ribozyme

    Science.gov (United States)

    Patwardhan, Anjali A.

    The antibacterial activity of aminoglycosides stems from their high affinity binding to the 16S rRNA in bacteria resulting in inhibition of protein synthesis. Used to treat acute bacterial infections these antibiotics have limited applications due to their high dosage requirements and the emergence of resistant strains. We have synthesized and characterized Cu(II) derivatives of the aminoglycosides, kanamycin A, tobramycin, neamine, kanamycin B, neomycin B, and paromomycin. The first three exhibit preferential and tight binding to Cu(II) as against neomycin B and kanamycin B and paromomycin. EPR of frozen solutions and UV-visible spectroscopy suggest a change in geometry around the Cu(II) but the stabilities of the complexes in water differ. These copper derivatives efficiently cleave plasmid DNA at micromolar concentrations (hydrolytic) and at nanomolar concentrations in the presence co-reactants like hydrogen peroxide or ascorbic acid. Hydrolysis is multi turnover and exhibits Michelis-Menten kinetics with enzyme-like behavior whereas oxidative cleavage is highly specific with C-4' H abstraction resulting in characteristic base propenal and nucleotide base products. Hydroxyl radicals generated are copper based and are generated in close proximity of the substrate. Hammerhead ribozymes are selectively hydrolyzed in the presence of divalent ions with Mg2+ being the metal ion of choice in vivo . Our studies with complex ions like cobalt hexaammine and fac-triamminetriaquochromium(III) establish outer sphere interactions of Mg2+ with the hammerhead in the catalytic site. There are two sets of sites, one structural and one catalytic. Complex ions in the catalytic site and divalent ions in the structural site result in a slow but active hammerhead ribozyme suggesting that the complex ions are not inhibitory, contrary to what was suggested previously.

  20. Prevalence of plasmid-mediated quinolone resistance and aminoglycoside resistance determinants among carbapeneme non-susceptible Enterobacter cloacae.

    Directory of Open Access Journals (Sweden)

    Shifeng Huang

    Full Text Available BACKGROUND: Simultaneous resistance to aminoglycosides and fluoroquinolones in carbapeneme non-susceptible (CNS isolates will inevitably create problems. The present study was performed to characterize the prevalence of the plasmid-mediated quinolone resistance determinants (QRDs and aminoglycoside resistance determinants (ARDs among the CNS Enterobacter cloacae (E. cloacae isolates in a Chinese teaching hospital, and to acquire their molecular epidemiological characteristics. METHODS: The β-lactamases genes (including class A carbapenemase genes bla(KPC and bla(SME, metallo-β-lactamase genes (MBLs bla(IMP, bla(VIM and bla(NDM, and extended spectrum β-lactamases (ESBLs,bla(CTX-M, bla(TEM and bla(SHV, QRDs (including qnrA, qnrB, qnrS and aac(6'-Ib-cr and ARDs (including aac(6'-Ib, armA and rmtB of these 35 isolates were determined by PCR and sequenced bidirectionally. The clonal relatedness was investigated by pulsed-field gel electrophoresis (PFGE. RESULTS: Of the 35 isolates, 9 (25.7% harbored a carbapenemase gene; 23 (65.7% carried ESBLs; 24 (68.6% were QRD positive; and 27 (77.1% were ARD positive. Among the 5 bla(IMP-8 positive strains, 4 (80% contained both ESBL and QRD genes, and all the 5 (100% harbored ARD genes. Of the 23 ESBLs positive isolates, 6 (26.1% were carbapenemase positive, 14 (60.9% were QRD positive, and 18 (78.3% were ARD positive. PFGE revealed genetic diversity among the 35 isolates, indicating that the high prevalence of CNS E. cloacae isolates was not caused by clonal dissemination. CONCLUSION: QRD and ARD genes were highly prevalent among the CNS E. cloacae isolates. Multiple resistant genes were co-expressed in the same isolates. The CNS E. cloacae isolate co-expressing bla(NDM-1, bla(IMP-26, qnrA1 and qnrS1 was first reported.

  1. Adeno-associated virus-mediated Bcl-xL prevents aminoglycoside-induced hearing loss in mice

    Institute of Scientific and Technical Information of China (English)

    LIU Yu-he; KE Xiao-mei; QIN Yong; GU Zhi-ping; XIAO Shui-fang

    2007-01-01

    Background Recent studies showed that aminoglycosides destroyed the cochlear cells and induced ototoxicity by producing reactive oxygen species, including free radicals in the mitochondria, damaging the membrane of mitochondria and resulting in apoptotic cell death. Bcl-xL is a well characterized anti-apoptotic member of the Bcl-2 family. The aim of this study was to determine the potential cochlear protective effect of Bcl-xL as a therapeutic agent in the murine model of aminoglycoside ototoxicity.Methods Serotype 2 of adeno-associated virus (AAV2) as a vector encoding the mouse Bcl-xL gene was injected into mice cochleae prior to injection of kanamycin. Bcl-xL expression in vitro and in vivo was examined with Western blotting and immunohistochemistry separately. Cochlear dissection and auditory steady state responses were checked to evaluate the cochlear structure and function.Results The animals in the AAV2-Bcl-xL/kanamycin group displayed better auditory steady state responses hearing thresholds and cochlear structure than those in the artificial perilymph/kanamycin or AAV2-enhanced humanized green fluorescent protein/kanamycin control group at all tested frequencies. The auditory steady state responses hearing thresholds and cochlear structure in the inoculated side were better than that in the contralateral side.Conclusions AAV2-Bcl-xL afforded significant preservation of the cochlear hair cells against ototoxic insults and protected the cochlear function. AAV2-mediated Bcl-xL might be an approach with respect to potential therapeutic application in the cochlear degeneration.

  2. Evaluation of Antibacterial Activity of Aminoglycosides and Modulating the Essential Oil of Cymbopogon citratus (DC. Stapf

    Directory of Open Access Journals (Sweden)

    Saulo R. TINTINO

    2014-05-01

    Full Text Available  Several works demonstrated the importance of the study of natural products as an alternative source for new antimicrobial drugs or for modulators for these ones. In this point, the aim of this was to investigate the antibacterial activity and the possible interactions between the essential oil of Cymbopogon citratus alone and in association with aminoglycosides against standard and clinically isolated strains of multidrug-resistant bacteria such as S. aureus, E. coli and P. aeruginosa by microdilution method. The results indicated a synergism between the antibiotics and the essential oil with a subinhibitory concentration (MIC/8, reducing the minimal inhibitory concentration (MIC sixteen times against the multidrug-resistant strains of S. aureus 358, E. coli 27 and P. aeruginosa 143, but none modulatory activity was observed against P. aeruginosa 78 and P. aeruginosa 91 strains. By our results, can be concluded that the essential oil of Cymbopogon citratus can be an interesting source of natural products with antibacterial and/or modulatory antibiotic activitieAVALIAÇÃO DA ATIVIDADE ANTIBACTERIANA E MODULADORA DE AMINOGLICOSÍDEOS DO ÓLEO ESSENCIAL DE Cymbopogon citratus (DC. STAPFVários trabalhos vêm demonstrando a importância do estudo de produtos naturais como fonte alternativa para novos antimicrobianos ou que venham potencializar os já existentes. Neste contexto este trabalho teve como objetivo investigar a atividade antibacteriana e as possíveis interações entre o óleo essencial de Cymbopogon citratus combinados a aminoglicosídeos frente a linhagens padrões e multirresistentes de S. aureus, E. coli e de P. aeruginosa provenientes de isolados clínicos. Um ensaio de microdiluição foi realizado para verificar a atividade antibacteriana e as possíveis interacções entre o produto natural e os antibióticos, utilizando uma concentração sub-inibitória. Através dos resultados foi constatado a interferência sinérgica dos

  3. Enhancement of the antibiotic activity of aminoglycosides by extracts from Anadenanthera colubrine (Vell.) Brenan var. cebil against multi-drug resistant bacteria.

    Science.gov (United States)

    Barreto, Humberto M; Coelho, Kivia M R N; Ferreira, Josie H L; Dos Santos, Bernadete H C; de Abreu, Aislan P L; Coutinho, Henrique D M; da Silva, Romezio A C; de Sousa, Taciana O; Citó, Antonia M das G L; Lopes, José A D

    2016-06-01

    The aim of this work was to evaluate the antimicrobial activity of ethanol (EEAC) and hexane (HFAC) extracts from the stem bark of Anadenanthera colubrina (Vell.) Brenan var. cebil alone or in combination with aminoglycosides against multi-drug resistant (MDR) bacteria. Minimal inhibitory concentrations (MICs) of the extracts were determined by using microdilution assay. For the evaluation of extracts as modulators of antibiotic resistance, MICs of neomycin and amikacin were determined in presence or absence of each compound at sub-inhibitory concentrations. Both EEAC and HFAC did not show antimicrobial activity against MDR strains tested. However, the addition of EEAC and HFAC enhanced the activity of neomycin and amikacin against Staphylococcus aureus SA10 strain. When the natural products were replaced by chlorpromazine, the same effect was observed. Anadenanthera colubrine var. cebil may be a source of phytochemicals able to potentiate the aminoglycoside activity against MDR S. aureus by the inhibition of efflux pump. PMID:26158209

  4. Chemoprophylactic efficacy against experimental endocarditis caused by beta-lactamase-producing, aminoglycoside-resistant enterococci is associated with prolonged serum inhibitory activity.

    OpenAIRE

    Bayer, A S; Tu, J

    1990-01-01

    We studied the prevention of experimental aortic endocarditis caused by a beta-lactamase-producing, aminoglycoside-resistant strain of Enterococcus faecalis (HH22) in 146 catheterized rabbits. Both vancomycin and ampicillin-sulbactam readily killed this resistant enterococcus strain in vitro. At a challenge inoculum of approximately 10(9) CFU, vancomycin (40 mg/kg intravenously [i.v.]), ampicillin (40 mg/kg i.v.), or a combination of ampicillin plus a beta-lactamase inhibitor, sulbactam (20 m...

  5. Aminoglycoside antibiotics and the sensory hair cells of inner ear and lateral line system in the Atlantic cod, Gadus morhua: effects on fish hearing threshold

    OpenAIRE

    Faucher, Karine; Aas-Hansen, Øyvind; Damsgard, Borge; Bégout, Marie-Laure; Fuhr, Torgrim; Laukli, Einar; Stenklev, Niels-Christian

    2007-01-01

    The aims of the present study were to investigate: a) the potential involvement of the fish lateral line system in hearing at 250 Hz and b) the possible regeneration of the inner ear hair cells in the Atlantic cod (Gadus morhua). The inner ear and lateral line system of the Atlantic cod were inactivated using ototoxic aminoglycoside antibiotics by injection (gentamicin) or bath (gentamicin and streptomycin), respectively. Hearing thresholds were measured in the fish using the Auditory Brainst...

  6. In70 of plasmid pAX22, a bla(VIM-1)-containing integron carrying a new aminoglycoside phosphotransferase gene cassette.

    Science.gov (United States)

    Riccio, M L; Pallecchi, L; Fontana, R; Rossolini, G M

    2001-04-01

    An Achromobacter xylosoxydans strain showing broad-spectrum resistance to beta-lactams (including carbapenems) and aminoglycosides was isolated at the University Hospital of Verona (Verona, Italy). This strain was found to produce metallo-beta-lactamase activity and to harbor a 30-kb nonconjugative plasmid, named pAX22, carrying a bla(VIM-1) determinant inserted into a class 1 integron. Characterization of this integron, named In70, revealed an original array of four gene cassettes containing, respectively, the bla(VIM-1) gene and three different aminoglycoside resistance determinants, including an aacA4 allele, a new aph-like gene named aphA15, and an aadA1 allele. The aphA15 gene is the first example of an aph-like gene carried on a mobile gene cassette, and its product exhibits close similarity to the APH(3')-IIa aminoglycoside phosphotransferase encoded by Tn5 (36% amino acid identity) and to an APH(3')-IIb enzyme from Pseudomonas aeruginosa (38% amino acid identity). Expression of the cloned aphA15 gene in Escherichia coli reduced the susceptibility to kanamycin and neomycin as well as (slightly) to amikacin, netilmicin, and streptomycin. Characterization of the 5' and 3' conserved segments of In70 and of their flanking regions showed that In70 belongs to the group of class 1 integrons associated with defective transposon derivatives originating from Tn402-like elements. The structure of the 3' conserved segment indicates the closest ancestry with members of the In0-In2 lineage. In70, with its array of cassette-borne resistance genes, can mediate broad-spectrum resistance to most beta-lactams and aminoglycosides. PMID:11257042

  7. Increasing Prevalence of Aminoglycoside-Resistant Enterococcus faecalis Isolates Due to the aac(6’)-aph(2”) Gene: A Therapeutic Problem in Kermanshah, Iran

    Science.gov (United States)

    Khani, Mitra; Fatollahzade, Mahdie; Pajavand, Hamid; Bakhtiari, Somaye; Abiri, Ramin

    2016-01-01

    Background: Enterococci are important pathogens in nosocomial infections. Various types of antibiotics, such as aminoglycosides, are used for treatment of these infections. Enterococci can acquire resistant traits, which can lead to therapeutic problems with aminoglycosides. Objectives: This study was designed to identify the prevalence of, and to compare, the aac(6’)-aph(2”) and aph(3)-IIIa genes and their antimicrobial resistance patterns among Enterococcus faecalis and E. faecium isolates from patients at Imam Reza hospital in Kermanshah in 2011 - 2012. Patients and Methods: One hundred thirty-eight clinical specimens collected from different wards of Imam Reza hospital were identified to the species level by biochemical tests. Antimicrobial susceptibility tests against kanamycin, teicoplanin, streptomycin, imipenem, ciprofloxacin, and ampicillin were performed by the disk diffusion method. The minimum inhibitory concentrations of gentamicin, streptomycin, kanamycin, and amikacin were evaluated with the microbroth dilution method. The aminoglycoside resistance genes aac(6’)-aph(2”) and aph(3”)-IIIa were analyzed with multiplex PCR. Results: The prevalence of isolates was 33 (24.1%) for E. faecium and 63 (46%) for E. faecalis. Eighty-nine percent of the isolates were high-level gentamicin resistant (HLGR), and 32.8% of E. faecium isolates and 67.2% of E. faecalis isolates carried aac(6’)-aph(2”). The prevalence of aph(3”)-IIIa among the E. faecalis and E. faecium isolates was 22.7% and 77.3%, respectively. Conclusions: Remarkably increased incidence of aac(6’)-aph(2”) among HLGR isolates explains the relationship between this gene and the high level of resistance to aminoglycosides. As the resistant gene among enterococci can be transferred, the use of new-generation antibiotics is necessary.

  8. Development and evaluation of immunochromatography to detect Gram-negative bacteria producing ArmA 16S rRNA methylase responsible for aminoglycoside resistance.

    Science.gov (United States)

    Oshiro, Satoshi; Tada, Tatsuya; Kameoka, Yousuke; Suzuki, Kazuo; Ohmagari, Norio; Miyoshi-Akiyama, Tohru; Kirikae, Teruo

    2015-11-01

    Rapid and reliable detection of aminoglycoside-resistant bacteria is an important infection-control measure and a crucial aspect of antimicrobial chemotherapy. The enzyme 16S rRNA methylase has been shown to mediate aminoglycoside resistance in bacteria. This study describes a newly developed immunochromatographic assay using novel monoclonal antibodies (mAbs) that recognize ArmA 16S rRNA methylase. Epitope mapping showed that these mAbs recognized amino acids 1-93 of ArmA, which consists of 257 amino acids. Evaluation of the assay using ArmA producing and non-producing bacterial species, as well as bacteria producing other types of 16S rRNA methylases, indicated that immunochromatographic detection of the ArmA-type 16S rRNA methylase was fully consistent with PCR analysis for armA genes, with all immunochromatographically positive strains being resistant to aminoglycosides (MIC≥128μg/mL). The detection limit of the assay was 12ng ArmA. These findings indicate that this assay can be used for the rapid and reliable detection of the production of ArmA 16S rRNA methylase by Gram-negative bacteria, including Acinetobacter baumannii and Escherichia coli. PMID:26381663

  9. Resistance-nodulation-cell division-type efflux pump involved in aminoglycoside resistance in Acinetobacter baumannii strain BM4454.

    Science.gov (United States)

    Magnet, S; Courvalin, P; Lambert, T

    2001-12-01

    Multidrug-resistant strain Acinetobacter baumannii BM4454 was isolated from a patient with a urinary tract infection. The adeB gene, which encodes a resistance-nodulation-cell division (RND) protein, was detected in this strain by PCR with two degenerate oligodeoxynucleotides. Insertional inactivation of adeB in BM4454, which generated BM4454-1, showed that the corresponding protein was responsible for aminoglycoside resistance and was involved in the level of susceptibility to other drugs including fluoroquinolones, tetracyclines, chloramphenicol, erythromycin, trimethoprim, and ethidium bromide. Study of ethidium bromide accumulation in BM4454 and BM4454-1, in the presence or in the absence of carbonyl cyanide m-chlorophenylhydrazone, demonstrated that AdeB was responsible for the decrease in intracellular ethidium bromide levels in a proton motive force-dependent manner. The adeB gene was part of a cluster that included adeA and adeC which encodes proteins homologous to membrane fusion and outer membrane proteins of RND-type three-component efflux systems, respectively. The products of two upstream open reading frames encoding a putative two-component regulatory system might be involved in the regulation of expression of the adeABC gene cluster. PMID:11709311

  10. Hair cell stereociliary bundle regeneration by espin gene transduction after aminoglycoside damage and hair cell induction by Notch inhibition.

    Science.gov (United States)

    Taura, A; Taura, K; Koyama, Y; Yamamoto, N; Nakagawa, T; Ito, J; Ryan, A F

    2016-05-01

    Once inner ear hair cells (HCs) are damaged by drugs, noise or aging, their apical structures including the stereociliary arrays are frequently the first cellular feature to be lost. Although this can be followed by progressive loss of HC somata, a significant number of HC bodies often remain even after stereociliary loss. However, in the absence of stereocilia they are nonfunctional. HCs can sometimes be regenerated by Atoh1 transduction or Notch inhibition, but they also may lack stereociliary bundles. It is therefore important to develop methods for the regeneration of stereocilia, in order to achieve HC functional recovery. Espin is an actin-bundling protein known to participate in sterociliary elongation during development. We evaluated stereociliary array regeneration in damaged vestibular sensory epithelia in tissue culture, using viral vector transduction of two espin isoforms. Utricular HCs were damaged with aminoglycosides. The utricles were then treated with a γ-secretase inhibitor, followed by espin or control transduction and histochemistry. Although γ-secretase inhibition increased the number of HCs, few had stereociliary arrays. In contrast, 46 h after espin1 transduction, a significant increase in hair-bundle-like structures was observed. These were confirmed to be immature stereociliary arrays by scanning electron microscopy. Increased uptake of FM1-43 uptake provided evidence of stereociliary function. Espin4 transduction had no effect. The results demonstrate that espin1 gene therapy can restore stereocilia on damaged or regenerated HCs. PMID:26886463

  11. Determination of aminoglycosides in honey by capillary electrophoresis tandem mass spectrometry and extraction with molecularly imprinted polymers.

    Science.gov (United States)

    Moreno-González, David; Lara, Francisco J; Jurgovská, Nikola; Gámiz-Gracia, Laura; García-Campaña, Ana M

    2015-09-01

    A new analytical method based on capillary zone electrophoresis-tandem mass spectrometry is proposed and validated for the identification and simultaneous quantification of nine aminoglycosides in honey samples. Detection using an ion trap mass analyzer operating in the multiple reaction monitoring mode was used. Different parameters were optimized in order to obtain an adequate separation combined with the highest sensitivity. In order to achieve high selectivity in the sample treatment, a commercially-available molecularly imprinted polymer has been used for the solid phase extraction of the analytes. Under optimum conditions, recoveries for fortified samples ranged from 88.2 to 99.8%, with relative standard deviations lower than 8%. The limits of detection ranged from 0.4 to 28.5 μg kg(-1). Furthermore, the decision limit and the detection capability were evaluated, ranging from 3.5 to 60.5 μg kg(-1) and from 6.0 to 103.1 μg kg(-1), respectively, demonstrating the sensitivity and applicability of this fast and simple method. PMID:26388393

  12. Special characteristics of fluorescence and resonance Rayleigh scattering for cadmium telluride nanocrystal aqueous solution and its interactions with aminoglycoside antibiotics

    Institute of Scientific and Technical Information of China (English)

    LI TaiShan; LIU ShaoPu; LIU ZhongFang; HU XiaoLi; ZHANG LiPing

    2009-01-01

    CdTe nanocrystals (CdTe NCs) were achieved by reaction of CdCl2 with KHTe solution and were capped with sodium mercaptoacetate. The product was detected by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS), fluorescence spectra, ultraviolet-visible spectra and X-ray diffraction (XRD). The CdTe NCs are of cubic structure and the average size is about 5 nm. The fluorescence quantum yield of CdTe NCs aqueous solution increased from 37% to 97% after 20 d under room light. The maximum λem of fluorescence changed from 543 nm to 510 nm and the blue shift was 33 nm. CdTe NCs aqueous solution can be steady for at least 10 months at 4℃ in a refrigerator. The resonance Rayleigh scattering (RRS) of CdTe NCs in the aqueous solution was investigated. The maximum scattering peak was located at about 554 nm. The interactions of CdTe NCs with amikacin sulfate (AS) and micronomicin sulfate (MS) were in-vestigated respectively. The effects of AS and MS on fluorescence and RRS of CdTe NCs were analyzed. It was found that AS and MS quenched the photoluminescence of CdTe NCs and enhanced RRS of CdTe NCs. Under optimum conditions, there are linear relationships between quenching intensity (F0-F), intensity of RRS (1-10) and concentration of AS and MS. The detection limits (3σ) of AS and MS are re-spectively 3.4 ng.mL-1 and 2.6 ng.mL-1 by the fluorescence quenching method, and 15.2 ng.mL-1 and 14.0 ng.mL-1 by the RRS method. The methods have high sensitivity, thus CdTe NCs may be used as fluorescence probes and RRS probes for the detection of aminoglycoside antibiotics.

  13. Kinetics of kill of bacterial conjunctivitis isolates with moxifloxacin, a fluoroquinolone, compared with the aminoglycosides tobramycin and gentamicin

    Directory of Open Access Journals (Sweden)

    Rudolph S Wagner

    2010-01-01

    Full Text Available Rudolph S Wagner1, David B Granet2, Steven J Lichtenstein3, Tiffany Jamison4, Joseph J Dajcs4, Robert D Gross5, Paul Cockrum41New Jersey Medical School, Newark, NJ, USA; 2Ratner Children’s Eye Center, University of California – San Diego, La Jolla, CA, USA; 3University of Illinois College of Medicine at Peoria, Peoria, Illinois, USA; 4Alcon Research, Ltd, Fort Worth, TX, USA; 5Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX, USAPurpose: To compare the kinetics and speed of kill of Streptococcus pneumoniae and Haemophilus influenzae on exposure to three topical ophthalmic antibiotic solutions.Materials and methods: Bacterial conjunctivitis isolates of S. pneumoniae and H. influenzae were exposed to 1:1000 dilutions of moxifloxacin 0.5%, tobramycin 0.3%, gentamicin 0.3%, and water (control. At 15, 30, 60, 120, and 180 minutes after exposure, aliquots were collected, cells were cultured, and viable cell counts were determined using standard microbiological methods.Results: Moxifloxacin achieved 99.9% kill (3-log reduction at approximately 2 hours for S. pneumoniae and at 15 minutes for H. influenzae. Tobramycin and gentamicin did not achieve 3-log reduction of S. pneumoniae during the 180-minute study period. An increase in bacterial growth was noted for these isolates. Gentamicin took more than 120 minutes to achieve the 3-log reduction of H. influenzae and tobramycin did not reach the 3-log reduction of this pathogen during the 180-minute study period.Conclusion: Moxifloxacin killed S. pneumoniae and H. influenzae in vitro faster than tobramycin and gentamicin, suggesting its potential clinical benefit as a first-line treatment for bacterial conjunctivitis to minimize patient symptoms and to limit the contagiousness of the disease.Keywords: kinetics of kill, bacterial conjunctivitis, in vitro, Streptococcus pneumoniae, Haemophilus influenzae, fluoroquinolones, aminoglycosides

  14. Comparative Proteomic Analysis of Aminoglycosides Resistant and Susceptible Mycobacterium tuberculosis Clinical Isolates for Exploring Potential Drug Targets.

    Directory of Open Access Journals (Sweden)

    Divakar Sharma

    Full Text Available Aminoglycosides, amikacin (AK and kanamycin (KM are second line anti-tuberculosis drugs used to treat tuberculosis (TB and resistance to them affects the treatment. Membrane and membrane associated proteins have an anticipated role in biological processes and pathogenesis and are potential targets for the development of new diagnostics/vaccine/therapeutics. In this study we compared membrane and membrane associated proteins of AK and KM resistant and susceptible Mycobacterium tuberculosis isolates by 2DE coupled with MALDI-TOF/TOF-MS and bioinformatic tools. Twelve proteins were found to have increased intensities (PDQuest Advanced Software in resistant isolates and were identified as ATP synthase subunit alpha (Rv1308, Trigger factor (Rv2462c, Dihydrolipoyl dehydrogenase (Rv0462, Elongation factor Tu (Rv0685, Transcriptional regulator MoxR1(Rv1479, Universal stress protein (Rv2005c, 35kDa hypothetical protein (Rv2744c, Proteasome subunit alpha (Rv2109c, Putative short-chain type dehydrogenase/reductase (Rv0148, Bacterioferritin (Rv1876, Ferritin (Rv3841 and Alpha-crystallin/HspX (Rv2031c. Among these Rv2005c, Rv2744c and Rv0148 are proteins with unknown functions. Docking showed that both drugs bind to the conserved domain (Usp, PspA and SDR domain of these hypothetical proteins and GPS-PUP predicted potential pupylation sites within them. Increased intensities of these proteins and proteasome subunit alpha might not only be neutralized/modulated the drug molecules but also involved in protein turnover to overcome the AK and KM resistance. Besides that Rv1876, Rv3841 and Rv0685 were found to be associated with iron regulation signifying the role of iron in resistance. Further research is needed to explore how these potential protein targets contribute to resistance of AK and KM.

  15. Comparative Proteomic Analysis of Aminoglycosides Resistant and Susceptible Mycobacterium tuberculosis Clinical Isolates for Exploring Potential Drug Targets

    Science.gov (United States)

    Sharma, Divakar; Kumar, Bhavnesh; Lata, Manju; Joshi, Beenu; Venkatesan, Krishnamurthy; Shukla, Sangeeta; Bisht, Deepa

    2015-01-01

    Aminoglycosides, amikacin (AK) and kanamycin (KM) are second line anti-tuberculosis drugs used to treat tuberculosis (TB) and resistance to them affects the treatment. Membrane and membrane associated proteins have an anticipated role in biological processes and pathogenesis and are potential targets for the development of new diagnostics/vaccine/therapeutics. In this study we compared membrane and membrane associated proteins of AK and KM resistant and susceptible Mycobacterium tuberculosis isolates by 2DE coupled with MALDI-TOF/TOF-MS and bioinformatic tools. Twelve proteins were found to have increased intensities (PDQuest Advanced Software) in resistant isolates and were identified as ATP synthase subunit alpha (Rv1308), Trigger factor (Rv2462c), Dihydrolipoyl dehydrogenase (Rv0462), Elongation factor Tu (Rv0685), Transcriptional regulator MoxR1(Rv1479), Universal stress protein (Rv2005c), 35kDa hypothetical protein (Rv2744c), Proteasome subunit alpha (Rv2109c), Putative short-chain type dehydrogenase/reductase (Rv0148), Bacterioferritin (Rv1876), Ferritin (Rv3841) and Alpha-crystallin/HspX (Rv2031c). Among these Rv2005c, Rv2744c and Rv0148 are proteins with unknown functions. Docking showed that both drugs bind to the conserved domain (Usp, PspA and SDR domain) of these hypothetical proteins and GPS-PUP predicted potential pupylation sites within them. Increased intensities of these proteins and proteasome subunit alpha might not only be neutralized/modulated the drug molecules but also involved in protein turnover to overcome the AK and KM resistance. Besides that Rv1876, Rv3841 and Rv0685 were found to be associated with iron regulation signifying the role of iron in resistance. Further research is needed to explore how these potential protein targets contribute to resistance of AK and KM. PMID:26436944

  16. Purification, crystallization and preliminary X-ray analysis of aminoglycoside-2′′-phosphotransferase-Ic [APH(2′′)-Ic] from Enterococcus gallinarum

    International Nuclear Information System (INIS)

    APH(2′′)-Ic is an enzyme that is responsible for high-level gentamicin resistance in E. gallinarum isolates. Crystals of the wild-type enzyme and three mutants have been prepared and a complete X-ray diffraction data set was collected to 2.15 Å resolution from an F108L crystal. Bacterial resistance to aminoglycoside antibiotics is primarily the result of deactivation of the drugs. Three families of enzymes are responsible for this activity, with one such family being the aminoglycoside phosphotransferases (APHs). The gene encoding one of these enzymes, aminoglycoside-2′′-phosphotransferase-Ic [APH(2′′)-Ic] from Enterococcus gallinarum, has been cloned and the wild-type protein (comprising 308 amino-acid residues) and three mutants that showed elevated minimum inhibitory concentrations towards gentamicin (F108L, H258L and a double mutant F108L/H258L) were expressed in Escherichia coli and subsequently purified. All APH(2′′)-Ic variants were crystallized in the presence of 14–20%(w/v) PEG 4000, 0.25 M MgCl2, 0.1 M Tris–HCl pH 8.5 and 1 mM Mg2GTP. The crystals belong to the monoclinic space group C2, with one molecule in the asymmetric unit. The approximate unit-cell parameters are a = 82.4, b = 54.2, c = 77.0 Å, β = 108.8°. X-ray diffraction data were collected to approximately 2.15 Å resolution from an F108L crystal at beamline BL9-2 at SSRL, Stanford, California, USA

  17. Ex vivo treatment with a novel synthetic aminoglycoside NB54 in primary fibroblasts from Rett syndrome patients suppresses MECP2 nonsense mutations.

    Directory of Open Access Journals (Sweden)

    Manuela Vecsler

    Full Text Available BACKGROUND: Nonsense mutations in the X-linked methyl CpG-binding protein 2 (MECP2 comprise a significant proportion of causative MECP2 mutations in Rett syndrome (RTT. Naturally occurring aminoglycosides, such as gentamicin, have been shown to enable partial suppression of nonsense mutations related to several human genetic disorders, however, their clinical applicability has been compromised by parallel findings of severe toxic effects. Recently developed synthetic NB aminoglycosides have demonstrated significantly improved effects compared to gentamicin evident in substantially higher suppression and reduced acute toxicity in vitro. RESULTS: We performed comparative study of suppression effects of the novel NB54 and gentamicin on three MECP2 nonsense mutations (R294X, R270X and R168X common in RTT, using ex vivo treatment of primary fibroblasts from RTT patients harboring these mutations and testing for the C-terminal containing full-length MeCP2. We observed that NB54 induces dose-dependent suppression of MECP2 nonsense mutations more efficiently than gentamicin, which was evident at concentrations as low as 50 µg/ml. NB54 read-through activity was mutation specific, with maximal full-length MeCP2 recovery in R168X (38%, R270X (27% and R294X (18%. In addition, the recovered MeCP2 was translocated to the cell nucleus and moreover led to parallel increase in one of the most important MeCP2 downstream effectors, the brain derived neurotrophic factor (BDNF. CONCLUSION: Our findings suggest that NB54 may induce restoration of the potentially functional MeCP2 in primary RTT fibroblasts and encourage further studies of NB54 and other rationally designed aminoglycoside derivatives as potential therapeutic agents for nonsense MECP2 mutations in RTT.

  18. Combinations of β-lactam or aminoglycoside antibiotics with plectasin are synergistic against methicillin-sensitive and methicillin-resistant Staphylococcus aureus.

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    Yanmin Hu

    Full Text Available Bacterial infections remain the leading killer worldwide which is worsened by the continuous emergence of antibiotic resistance. In particular, methicillin-sensitive (MSSA and methicillin-resistant Staphylococcus aureus (MRSA are prevalent and the latter can be difficult to treat. The traditional strategy of novel therapeutic drug development inevitably leads to emergence of resistant strains, rendering the new drugs ineffective. Therefore, rejuvenating the therapeutic potentials of existing antibiotics offers an attractive novel strategy. Plectasin, a defensin antimicrobial peptide, potentiates the activities of other antibiotics such as β-lactams, aminoglycosides and glycopeptides against MSSA and MRSA. We performed in vitro and in vivo investigations to test against genetically diverse clinical isolates of MSSA (n = 101 and MRSA (n = 115. Minimum inhibitory concentrations (MIC were determined by the broth microdilution method. The effects of combining plectasin with β-lactams, aminoglycosides and glycopeptides were examined using the chequerboard method and time kill curves. A murine neutropenic thigh model and a murine peritoneal infection model were used to test the effect of combination in vivo. Determined by factional inhibitory concentration index (FICI, plectasin in combination with aminoglycosides (gentamicin, neomycin or amikacin displayed synergistic effects in 76-78% of MSSA and MRSA. A similar synergistic response was observed when plectasin was combined with β-lactams (penicillin, amoxicillin or flucloxacillin in 87-89% of MSSA and MRSA. Interestingly, no such interaction was observed when plectasin was paired with vancomycin. Time kill analysis also demonstrated significant synergistic activities when plectasin was combined with amoxicillin, gentamicin or neomycin. In the murine models, plectasin at doses as low as 8 mg/kg augmented the activities of amoxicillin and gentamicin in successful treatment of MSSA and MRSA

  19. Salmonella enterica Serovar Typhimurium blaPER-1-Carrying Plasmid pSTI1 Encodes an Extended-Spectrum Aminoglycoside 6′-N-Acetyltransferase of Type Ib

    OpenAIRE

    Casin, Isabelle; Hanau-Berçot, Beatrice; Podglajen, Isabelle; Vahaboglu, Haluk; Collatz, Ekkehard

    2003-01-01

    We have studied the aminoglycoside resistance gene, which confers high levels of resistance to both amikacin and gentamicin, that is carried by plasmid pSTI1 in the PER-1 β-lactamase-producing strain of Salmonella enterica serovar Typhimurium previously isolated in Turkey. This gene, called aac(6′)-Ib11, was found in a class 1 integron and codes for a protein of 188 amino acids, a fusion product between the N-terminal moiety (8 amino acids) of the signal peptide of the β-lactamase OXA-1 and t...

  20. Identification of a novel 6'-N-aminoglycoside acetyltransferase, AAC(6')-Iak, from a multidrug-resistant clinical isolate of Stenotrophomonas maltophilia.

    Science.gov (United States)

    Tada, Tatsuya; Miyoshi-Akiyama, Tohru; Dahal, Rajan K; Mishra, Shyam K; Shimada, Kayo; Ohara, Hiroshi; Kirikae, Teruo; Pokhrel, Bharat M

    2014-10-01

    Stenotrophomonas maltophilia IOMTU250 has a novel 6'-N-aminoglycoside acetyltransferase-encoding gene, aac(6')-Iak. The encoded protein, AAC(6')-Iak, consists of 153 amino acids and has 86.3% identity to AAC(6')-Iz. Escherichia coli transformed with a plasmid containing aac(6')-Iak exhibited decreased susceptibility to arbekacin, dibekacin, neomycin, netilmicin, sisomicin, and tobramycin. Thin-layer chromatography showed that AAC(6')-Iak acetylated amikacin, arbekacin, dibekacin, isepamicin, kanamycin, neomycin, netilmicin, sisomicin, and tobramycin but not apramycin, gentamicin, or lividomycin. PMID:25092711

  1. Analysis of 76 veterinary pharmaceuticals from 13 classes including aminoglycosides in bovine muscle by hydrophilic interaction liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Dasenaki, Marilena E; Michali, Christina S; Thomaidis, Nikolaos S

    2016-06-24

    A multiresidue/multiclass method for the simultaneous determination of 76 veterinary drugs and pharmaceuticals in bovine muscle tissue has been developed and validated according to the requirements of European Commission Decision 2002/657/EC. The analytes belong in 13 different classes, including aminoglycoside antibiotics, whose different physicochemical properties (extremely polar character) render their simultaneous determination with other veterinary drugs quite problematic. The method combines a two-step extraction procedure (extraction with acetonitrile followed by an acidic aqueous buffer extraction) with hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) determination, allowing confirmation and quantification in a single chromatographic run. Further cleanup with solid phase extraction was performed using polymeric SPE cartridges. A thorough ionization study of aminoglycosides was performed in order to increase their sensitivity and significant differences in the abundance of the precursor ions of the analytes were revealed, depending on the composition of the mobile phase tested. Further gradient elution optimization and injection solvent optimization were performed for all target analytes.The method was validated according to the European Commission Decision 2002/657. Quantitative analysis was performed by means of standard addition calibration. Recoveries varied from 37.4% (bromhexine) to 106% (kanamycin) in the lowest validation level and 82% of the compounds showed recovery >70%. Detection capability (CCβ) varied from 2.4 (salinomycin) to 1302 (apramycin) μgkg(-1). PMID:27215463

  2. A nanoplex PCR assay for the rapid detection of vancomycin and bifunctional aminoglycoside resistance genes in Enterococcus species

    Directory of Open Access Journals (Sweden)

    Ravichandran Manickam

    2007-12-01

    Full Text Available Abstract Background Enterococci have emerged as a significant cause of nosocomial infections in many parts of the world over the last decade. The most common enterococci strains present in clinical isolates are E. faecalis and E. faecium which have acquired resistant to either gentamicin or vancomycin. The conventional culture test takes 2–5 days to yield complete information of the organism and its antibiotic sensitivity pattern. Hence our present study was focused on developing a nanoplex PCR assay for the rapid detection of vancomycin and bifunctional aminoglycoside resistant enterococci (V-BiA-RE. This assay simultaneously detects 8 genes namely 16S rRNA of Enterococcus genus, ddl of E. faecalis and E. faecium, aacA-aphD that encodes high level gentamicin resistance (HLGR, multilevel vancomycin resistant genotypes such as vanA, vanB, vanC and vanD and one internal control gene. Results Unique and specific primer pairs were designed to amplify the 8 genes. The specificity of the primers was confirmed by DNA sequencing of the nanoplex PCR products and BLAST analysis. The sensitivity and specificity of V-BiA-RE nanoplex PCR assay was evaluated against the conventional culture method. The analytical sensitivity of the assay was found to be 1 ng at the DNA level while the analytical specificity was evaluated with 43 reference enterococci and non-enterococcal strains and was found to be 100%. The diagnostic accuracy was determined using 159 clinical specimens, which showed that 97% of the clinical isolates belonged to E. faecalis, of which 26% showed the HLGR genotype, but none were vancomycin resistant. The presence of an internal control in the V-BiA-RE nanoplex PCR assay helped us to rule out false negative cases. Conclusion The nanoplex PCR assay is robust and can give results within 4 hours about the 8 genes that are essential for the identification of the most common Enterococcus spp. and their antibiotic sensitivity pattern. The PCR assay

  3. Special characteristics of fluorescence and resonance Rayleigh scattering for cadmium telluride nanocrystal aqueous solution and its interactions with aminoglycoside antibiotics

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    CdTe nanocrystals(CdTe NCs) were achieved by reaction of CdCl2 with KHTe solution and were capped with sodium mercaptoacetate.The product was detected by transmission electron microscopy(TEM),high-resolution transmission electron microscopy(HRTEM),energy dispersive spectroscopy(EDS),fluorescence spectra,ultraviolet-visible spectra and X-ray diffraction(XRD).The CdTe NCs are of cubic structure and the average size is about 5 nm.The fluorescence quantum yield of CdTe NCs aqueous solution increased from 37% to 97% after 20 d under room light.The maximum λem of fluorescence changed from 543 nm to 510 nm and the blue shift was 33 nm.CdTe NCs aqueous solution can be steady for at least 10 months at 4℃ in a refrigerator.The resonance Rayleigh scattering(RRS) of CdTe NCs in the aqueous solution was investigated.The maximum scattering peak was located at about 554 nm.The interactions of CdTe NCs with amikacin sulfate(AS) and micronomicin sulfate(MS) were investigated respectively.The effects of AS and MS on fluorescence and RRS of CdTe NCs were analyzed.It was found that AS and MS quenched the photoluminescence of CdTe NCs and enhanced RRS of CdTe NCs.Under optimum conditions,there are linear relationships between quenching intensity(F0-F),intensity of RRS(I-I0) and concentration of AS and MS.The detection limits(3б) of AS and MS are respectively 3.4 ng·mL-1 and 2.6 ng·mL-1 by the fluorescence quenching method,and 15.2 ng·mL-1 and 14.0 ng·mL-1 by the RRS method.The methods have high sensitivity,thus CdTe NCs may be used as fluorescence probes and RRS probes for the detection of aminoglycoside antibiotics.

  4. Clinical and molecular analysis of a four-generation Chinese family with aminoglycoside-induced and nonsyndromic hearing loss associated with the mitochondrial 12S rRNA C1494T mutation

    International Nuclear Information System (INIS)

    We report here the clinical, genetic, and molecular characterization of a four-generation Chinese family with aminoglycoside-induced and nonsyndromic hearing loss. Five of nine matrilineal relatives had aminoglycoside-induced hearing loss. These matrilineal relatives exhibited variable severity and audiometric configuration of hearing impairment, despite sharing some common features: being bilateral and having sensorineural hearing impairment. Sequence analysis of mitochondrial DNA (mtDNA) in the pedigree identified 16 variants and the homoplasmic 12S rRNA C1494T mutation, which was associated with hearing loss in the other large Chinese family. In fact, the occurrence of the C1494T mutation in these genetically unrelated pedigrees affected by hearing impairment strongly indicated that this mutation is involved in the pathogenesis of aminoglycoside-induced and nonsyndromic hearing loss. However, incomplete penetrance of hearing loss indicated that the C1494T mutation itself is not sufficient to produce a clinical phenotype but requires the involvement of modifier factors for the phenotypic expression. Those mtDNA variants, showing no evolutional conservation, may not have a potential modifying role in the pathogenesis of the C1494T mutation. However, nuclear background seems to contribute to the phenotypic variability of matrilineal relatives in this family. Furthermore, aminoglycosides modulate the expressivity and penetrance of deafness associated with the C1494T mutation in this family

  5. Mitochondrial DNA A1555G mutation screening using a testing kit method and its significance in preventing aminoglycoside-related hearing loss

    Institute of Scientific and Technical Information of China (English)

    LIU Xin; YANG Weiyan; HAN Dongyi; JIN Zhengce; GUAN Minxin; DAI Pu; HUANG Deliang; YUAN Huijun; LI Weiming; YU Fei; ZHANG Xin; KANG Dongyang; CAO Juyang

    2006-01-01

    To report a new screening method for mitochondrial DNA 1555A→G mutation and the results of genotype analysis in 19 maternal inherited deafness pedigrees. Method Five hundred and forty-six non-syndromic neuro-sensory hearing loss patients were tested for 1555A→G mutation using a new compact testing kit, which allows clear distinction between wild type and 1555 A→G mutated mtDNAs. Results Nineteen subjects among the 546 patients (3.48%) were found to carry mtDNA A1555G mutation. The results were confirmed by sequencing in an ABI 3100 Avant sequencer. Conclusions Maternal inherited deafness families are a frequently seen in outpatient group. The detection ofmtDNA 1555 A→G mutation with a low cost, ready to use detection kit is needed and suitable in China for large scale screening and preventive testing before usage of aminoglycoside antibiotics.

  6. Crystallization and X-ray analysis of 2-deoxy-scyllo-inosose synthase, the key enzyme in the biosynthesis of 2-deoxystreptamine-containing aminoglycoside antibiotics

    International Nuclear Information System (INIS)

    The crystallization of 2-deoxy-scyllo-inosose synthase, the key enzyme in the biosynthesis of 2-deoxystreptamine-containing aminoglycoside antibiotics, is reported. A recombinant 2-deoxy-scyllo-inosose synthase from Bacillus circulans has been crystallized at 277 K using PEG 4000 as precipitant. The diffraction pattern of the crystal extends to 2.30 Å resolution at 100 K using synchrotron radiation at the Photon Factory. The crystals are monoclinic and belong to space group P21, with unit-cell parameters a = 80.5, b = 70.4, c = 83.0 Å, β = 117.8°. The presence of two molecules per asymmetric unit gives a crystal volume per protein weight (VM) of 2.89 Å3 Da−1 and a solvent constant of 57.4% by volume

  7. Partial characterization of an endemic strain of a methicillin- and aminoglycoside-resistant Staphylococcus aureus (MARSA) homogeneously resistant to beta-lactam antibiotics.

    Science.gov (United States)

    Jacob, J; Meers, P D

    1992-06-01

    Selected strains of methicillin- and aminoglycoside-resistant Staphylococcus aureus (MARSA) were subjected to a preliminary examination. They were representative of a larger group collected in a routine clinical microbiology laboratory over a period of 2 years. MARSA was endemic in the associated hospital. The characteristics investigated were antimicrobial resistance, the production of beta-lactamase, free and bound coagulase, protein A, DNA-ase, urease, lipase and pigment. The MARSA strains were generally indistinguishable, other than in their antimicrobial resistances. The resistance to methicillin was completely homogeneous. Except with imipenem, growth extended to the edge of discs containing methicillin and the other beta-lactam antibiotics tested when the strains were cultured at 37 degrees C on media without added salt. Homogeneous resistance may confer an epidemiological advantage on strains of this phenotype. PMID:1353087

  8. The impact of methicillin- and aminoglycoside-resistant Staphylococcus aureus on the pattern of hospital-acquired infection in an acute hospital.

    Science.gov (United States)

    Meers, P D; Leong, K Y

    1990-10-01

    Infections due to methicillin- and aminoglycoside-resistant Staphylococcus aureus (MARSA) appeared in a new teaching hospital shortly after it opened. The effect this had on the pattern of hospital-acquired infections in the four years that followed is described. No control measures were applied and MARSA became endemic. New infections appeared at a rate of about four for each 1000 patients discharged. It established itself at different levels of incidence in various specialist units, patients under intensive care being most severely affected. MARSA was implicated in half of all hospital-acquired infections due to S. aureus but it was not more pathogenic than its more sensitive counterpart. It had little impact on the life of the hospital. PMID:1979573

  9. Nuclear modifier MTO2 modulates the aminoglycoside-sensitivity of mitochondrial 15S rRNA C1477G mutation in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Xiangyu He

    Full Text Available The phenotypic manifestations of mitochondrial DNA (mtDNA mutations are modulated by mitochondrial DNA haplotypes, nuclear modifier genes and environmental factors. The yeast mitochondrial 15S rRNA C1477G (P(R or P(R 454 mutation corresponds to the human 12S rRNA C1494T and A1555G mutations, which are well known as primary factors for aminoglycoside-induced nonsyndromic deafness. Here we report that the deletion of the nuclear modifier gene MTO2 suppressed the aminoglycoside-sensitivity of mitochondrial 15S rRNA C1477G mutation in Saccharomyces cerevisiae. First, the strain with a single mtDNA C1477G mutation exhibited hypersensitivity to neomycin. Functional assays indicated that the steady-state transcription level of mitochondrial DNA, the mitochondrial respiratory rate, and the membrane potential decreased significantly after neomycin treatment. The impaired mitochondria could not produce sufficient energy to maintain cell viability. Second, when the mto2 null and the mitochondrial C1477G mutations co-existed (mto2(P(R, the oxygen consumption rate in the double mutant decreased markedly compared to that of the control strains (MTO2(P(S, mto2(P(S and MTO2(P(R. The expression levels of the key glycolytic genes HXK2, PFK1 and PYK1 in the mto2(P(R strain were stimulated by neomycin and up-regulated by 89%, 112% and 55%, respectively. The enhanced glycolysis compensated for the respiratory energy deficits, and could be inhibited by the glycolytic enzyme inhibitor. Our findings in yeast will provide a new insight into the pathogenesis of human deafness.

  10. Distribution of 16S rRNA methylases among different species of Gram-negative bacilli with high-level resistance to aminoglycosides.

    Science.gov (United States)

    Zhou, Y; Yu, H; Guo, Q; Xu, X; Ye, X; Wu, S; Guo, Y; Wang, M

    2010-11-01

    16S rRNA methylases confer high-level resistance to most aminoglycosides in Gram-negative bacteria. Seven 16S rRNA methylase genes, armA, rmtA, rmtB, rmtC, rmtD, rmtE and npmA, have been identified since 2003. We studied the distribution of methylase genes in more than 200 aminoglycoside-resistant Gram-negative clinical isolates collected in 2007 at our hospital in Shanghai, China. 16S rRNA methylase genes were amplified by polymerase chain reaction (PCR) among 217 consecutive clinical isolates of Gram-negative bacilli resistant to gentamicin and amikacin by a disk diffusion method. 16S rRNA methylase genes were present in 97.5% (193/198) of clinical isolates highly resistant to amikacin (≥512 μg/ml), with armA and rmtB detected in 67.2 and 30.3% of strains, respectively, while no 16S rRNA methylase genes were detected in 19 strains with amikacin minimum inhibitory concentration (MIC) ≤256 μg/ml. armA or rmtB genes were detected in 100% of 104 strains of Enterobacteriaceae, and these two genes were equally represented (49 vs. 55 strains). Genes for armA or rmtB were detected in 94.7% (89/94) of Acinetobacter baumannii and Pseudomonas aeruginosa strains, and armA was predominant (84 vs. 5 strains with rmtB). No rmtA, rmtC, rmtD or npmA genes were found. Enterobacterial repetitive intergenic consensus sequence (ERIC-PCR) indicated that armA and rmtB genes were spread by both horizontal transfer and clonal dissemination. PMID:20614151

  11. Coexistence of mitochondrial 12S rRNA C1494T and CO1/tRNASer(UCN) G7444A mutations in two Han Chinese pedigrees with aminoglycoside-induced and non-syndromic hearing loss

    International Nuclear Information System (INIS)

    Mutations in mitochondrial DNA are one of the important causes of hearing loss. We report here the clinical, genetic, and molecular characterization of two Han Chinese pedigrees with maternally transmitted aminoglycoside-induced and nonsyndromic bilateral hearing loss. Clinical evaluation revealed the wide range of severity, age-at-onset, and audiometric configuration of hearing impairment in matrilineal relatives in these families. The penetrances of hearing loss in these pedigrees were 20% and 18%, when aminoglycoside-induced deafness was included. When the effect of aminoglycosides was excluded, the penetrances of hearing loss in these seven pedigrees were 10% and 15%. Sequence analysis of the complete mitochondrial genomes in these pedigrees showed the presence of the deafness-associated 12S rRNA C1494T and CO1/tRNASer(UCN) G7444A mutations. Their distinct sets of mtDNA polymorphism belonged to Eastern Asian haplogroup C4a1, while other previously identified six Chinese mitochondrial genomes harboring the C1494T mutation belong to haplogroups D5a2, D, R, and F1, respectively. This suggested that the C1494T or G7444A mutation occurred sporadically and multiplied through evolution of the mitochondrial DNA (mtDNA). The absence of functionally significant mutations in tRNA and rRNAs or secondary LHON mutations in their mtDNA suggest that these mtDNA haplogroup-specific variants may not play an important role in the phenotypic expression of the 12S rRNA C1494T and CO1/tRNASer(UCN) G7444A mutations in those Chinese families. However, aminoglycosides and other nuclear modifier genes play a modifying role in the phenotypic manifestation of the C1494T mutation in these Chinese families

  12. Mitochondrial COX2 G7598A Mutation May Have a Modifying Role in the Phenotypic Manifestation of Aminoglycoside Antibiotic-Induced Deafness Associated with 12S rRNA A1555G Mutation in a Han Chinese Pedigree

    OpenAIRE

    Chen, Tianbin; Liu, Qicai; Jiang, Ling; Liu, Can; Ou, Qishui

    2013-01-01

    Recent studies suggest that certain mitochondrial haplogroup markers and some specific variants in mitochondrial haplogroup may also influence the phenotypic expression of particular mitochondrial disorders. In this report, the clinical, genetic, and molecular characterization were identified in a Chinese pedigree with the aminoglycoside antibiotic (AmAn)-induced deafness and nonsyndromic hearing loss (NSHL). The pathogenic gene responsible for this hereditary NSHL pedigree was determined by ...

  13. Aminoglycoside-induced and non-syndromic hearing loss is associated with the G7444A mutation in the mitochondrial COI/tRNASer(UCN) genes in two Chinese families

    International Nuclear Information System (INIS)

    We report here the clinical, genetic, and molecular characterization of two Chinese families with aminoglycoside induced and non-syndromic hearing impairment. Clinical and genetic evaluations revealed the variable severity and age-of-onset in hearing impairment in these families. Strikingly, there were extremely low penetrances of hearing impairment in these Chinese families. Sequence analysis of the complete mitochondrial genomes in these pedigrees showed the distinct sets of mtDNA polymorphism, in addition to the identical G7444A mutation associated with hearing loss. Indeed, the G7444A mutation in the CO1 gene and the precursor of tRNASer(UCN) gene is present in homoplasmy only in the maternal lineage of those pedigrees but not other members of these families and 164 Chinese controls. Their mitochondrial genomes belong to the Eastern Asian haplogroups C5a and D4a, respectively. In fact, the occurrence of the G7444A mutation in these several genetically unrelated subjects affected by hearing impairment strongly indicates that this mutation is involved in the pathogenesis of hearing impairment. However, there was the absence of other functionally significant mtDNA mutations in two Chinese pedigrees carrying the G7444A mutation. Therefore, nuclear modifier gene(s) or aminoglycoside(s) may play a role in the phenotypic expression of the deafness-associated G7444A mutation in these Chinese pedigrees

  14. A Site-Specific Integrative Plasmid Found in Pseudomonas aeruginosa Clinical Isolate HS87 along with A Plasmid Carrying an Aminoglycoside-Resistant Gene.

    Directory of Open Access Journals (Sweden)

    Dexi Bi

    Full Text Available Plasmids play critical roles in bacterial fitness and evolution of Pseudomonas aeruginosa. Here two plasmids found in a drug-resistant P. aeruginosa clinical isolate HS87 were completely sequenced. The pHS87b plasmid (11.2 kb carries phage-related genes and function-unknown genes. Notably, pHS87b encodes an integrase and has an adjacent tRNAThr-associated attachment site. A corresponding integrated form of pHS87b at the tRNAThr locus was identified on the chromosome of P. aeruginosa, showing that pHS87b is able to site-specifically integrate into the 3'-end of the tRNAThr gene. The pHS87a plasmid (26.8 kb displays a plastic structure containing a putative replication module, stability factors and a variable region. The RepA of pHS87a shows significant similarity to the replication proteins of pPT23A-family plasmids. pHS87a carries a transposon Tn6049, a truncated insertion sequence ΔIS1071 and a Tn402-like class 1 integron which contains an aacA4 cassette that may confer aminoglycoside resistance. Thus, pHS87b is a site-specific integrative plasmid whereas pHS87a is a plastic antibiotic resistance plasmid. The two native plasmids may promote the fitness and evolution of P. aeruginosa.

  15. A Site-Specific Integrative Plasmid Found in Pseudomonas aeruginosa Clinical Isolate HS87 along with A Plasmid Carrying an Aminoglycoside-Resistant Gene.

    Science.gov (United States)

    Bi, Dexi; Xie, Yingzhou; Tai, Cui; Jiang, Xiaofei; Zhang, Jie; Harrison, Ewan M; Jia, Shiru; Deng, Zixin; Rajakumar, Kumar; Ou, Hong-Yu

    2016-01-01

    Plasmids play critical roles in bacterial fitness and evolution of Pseudomonas aeruginosa. Here two plasmids found in a drug-resistant P. aeruginosa clinical isolate HS87 were completely sequenced. The pHS87b plasmid (11.2 kb) carries phage-related genes and function-unknown genes. Notably, pHS87b encodes an integrase and has an adjacent tRNAThr-associated attachment site. A corresponding integrated form of pHS87b at the tRNAThr locus was identified on the chromosome of P. aeruginosa, showing that pHS87b is able to site-specifically integrate into the 3'-end of the tRNAThr gene. The pHS87a plasmid (26.8 kb) displays a plastic structure containing a putative replication module, stability factors and a variable region. The RepA of pHS87a shows significant similarity to the replication proteins of pPT23A-family plasmids. pHS87a carries a transposon Tn6049, a truncated insertion sequence ΔIS1071 and a Tn402-like class 1 integron which contains an aacA4 cassette that may confer aminoglycoside resistance. Thus, pHS87b is a site-specific integrative plasmid whereas pHS87a is a plastic antibiotic resistance plasmid. The two native plasmids may promote the fitness and evolution of P. aeruginosa. PMID:26841043

  16. Crystallographic Studies of Two Bacterial AntibioticResistance Enzymes: Aminoglycoside Phosphotransferase (2')-Ic and GES-1\\beta-lactamase

    Energy Technology Data Exchange (ETDEWEB)

    Brynes, Laura; /Rensselaer Poly.

    2007-10-31

    Guiana Extended-Spectrum-1 (GES-1) and Aminoglycoside phosphotransferase (2')-Ic (APH(2')-Ic) are two bacteria-produced enzymes that essentially perform the same task: they provide resistance to an array of antibiotics. Both enzymes are part of a growing resistance problem in the medical world. In order to overcome the ever-growing arsenal of antibiotic-resistance enzymes, it is necessary to understand the molecular basis of their action. Accurate structures of these proteins have become an invaluable tool to do this. Using protein crystallography techniques and X-ray diffraction, the protein structure of GES-1 bound to imipenem (an inhibitor) has been solved. Also, APH(2')-Ic has been successfully crystallized, but its structure was unable to be solved using molecular replacement using APH(2')-Ib as a search model. The structure of GES-1, with bound imipenem was solved to a resolution of 1.89A, and though the inhibitor is bound with only moderate occupancy, the structure shows crucial interactions inside the active site that render the enzyme unable to complete the hydrolysis of the {beta}-lactam ring. The APH(2')-Ic dataset could not be matched to the model, APH(2')-Ib, with which it shares 25% sequence identity. The structural information gained from GES-1, and future studies using isomorphous replacement to solve the APH(2')-Ic structure can aid directly to the creation of novel drugs to combat both of these classes of resistance enzymes.

  17. Potentiation of Aminoglycoside Activity in Pseudomonas aeruginosa by Targeting the AmgRS Envelope Stress-Responsive Two-Component System.

    Science.gov (United States)

    Poole, Keith; Gilmour, Christie; Farha, Maya A; Mullen, Erin; Lau, Calvin Ho-Fung; Brown, Eric D

    2016-06-01

    A screen for agents that potentiated the activity of paromomycin (PAR), a 4,5-linked aminoglycoside (AG), against wild-type Pseudomonas aeruginosa identified the RNA polymerase inhibitor rifampin (RIF). RIF potentiated additional 4,5-linked AGs, such as neomycin and ribostamycin, but not the clinically important 4,6-linked AGs amikacin and gentamicin. Potentiation was absent in a mutant lacking the AmgRS envelope stress response two-component system (TCS), which protects the organism from AG-generated membrane-damaging aberrant polypeptides and, thus, promotes AG resistance, an indication that RIF was acting via this TCS in potentiating 4,5-linked AG activity. Potentiation was also absent in a RIF-resistant RNA polymerase mutant, consistent with its potentiation of AG activity being dependent on RNA polymerase perturbation. PAR-inducible expression of the AmgRS-dependent genes htpX and yccA was reduced by RIF, suggesting that AG activation of this TCS was compromised by this agent. Still, RIF did not compromise the membrane-protective activity of AmgRS, an indication that it impacted some other function of this TCS. RIF potentiated the activities of 4,5-linked AGs against several AG-resistant clinical isolates, in two cases also potentiating the activity of the 4,6-linked AGs. These cases were, in one instance, explained by an observed AmgRS-dependent expression of the MexXY multidrug efflux system, which accommodates a range of AGs, with RIF targeting of AmgRS undermining mexXY expression and its promotion of resistance to 4,5- and 4,6-linked AGs. Given this link between AmgRS, MexXY expression, and pan-AG resistance in P. aeruginosa, RIF might be a useful adjuvant in the AG treatment of P. aeruginosa infections. PMID:27021319

  18. Determination of aminoglycoside residues in milk and muscle based on a simple and fast extraction procedure followed by liquid chromatography coupled to tandem mass spectrometry and time of flight mass spectrometry.

    Science.gov (United States)

    Arsand, Juliana Bazzan; Jank, Louíse; Martins, Magda Targa; Hoff, Rodrigo Barcellos; Barreto, Fabiano; Pizzolato, Tânia Mara; Sirtori, Carla

    2016-07-01

    Antibiotics are widely used in veterinary medicine mainly for treatment and prevention of diseases. The aminoglycosides are one of the antibiotics classes that have been extensively employed in animal husbandry for the treatment of bacterial infections, but also as growth promotion. The European Union has issued strict Maximum Residue Levels (MRLs) for aminoglycosides in several animal origin products including bovine milk, bovine, swine and poultry muscle. This paper describes a fast and simple analytical method for the determination of ten aminoglycosides (spectinomycin, tobramycin, gentamicin, kanamycin, hygromycin, apramycin, streptomycin, dihydrostreptomycin, amikacin and neomycin) in bovine milk and bovine, swine and poultry muscle. For sample preparation, an extraction method was developed using trichloroacetic acid and clean up with low temperature precipitation and C18 bulk. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was used to carry out quantitative analysis and liquid chromatography-quadrupole-time of flight-mass spectrometry (LC-QTOF-MS) was used to screening purposes. Both methods were validated according to the European Union Commission Directive 2002/657/EC. Good performance characteristics were obtained for recovery, precision, calibration curve, specificity, decision limits (CCα) and detection capabilities (CCβ) in all matrices evaluated. The detection limit (LOD) and quantification limit (LOQ) were ranging from 5 to 100ngg(-1) and 12.5 to 250ngg(-1), respectively. Good linearity (r)-above 0.99-was achieved in concentrations ranging from 0.0 to 2.0×MRL. Recoveries ranged from 36.8% to 98.0% and the coefficient of variation from 0.9 to 20.2%, noting that all curves have been made into their own matrices in order to minimize the matrix effects. The CCβ values obtained in qualitative method were between 25 and 250ngg(-1). The proposed method showed to be simple, easy, and adequate for high-throughput analysis of a large

  19. Synthèse d'analogues d'aminoglycosides par voie chimique et ingénierie métabolique : Application à l'étude des ARN par RMN du fluor

    OpenAIRE

    Lombès, Thomas

    2012-01-01

    Les ARN constituent des cibles thérapeutiques extrêmement intéressantes bien qu'encore assez peu exploitées. En effet, les obstacles pour la conception de ligands spécifiques de ces cibles non traditionnelles, polyanioniques et très flexibles, sont encore loin d'être levés. Les aminoglycosides, utilisés depuis longtemps pour leurs propriétés antibiotiques, sont souvent décrits comme des " ligands universels " d'ARN. Leur structure constitue donc une architecture favorable pour l'élaboration d...

  20. 两个携带线粒体12S rRNA 1494C>T突变的耳聋家系的遗传学特征%Characterization of two Chinese families with aminoglycoside-induced and nonsyndromic hearing loss both carrying a mitochondrial 12S rRNA 1494C>T mutation

    Institute of Scientific and Technical Information of China (English)

    龚莎莎; 管敏鑫; 陈波蓓; 彭光华; 郑静; 张婷; 郑斌娇; 方芳; 张初琴; 吕建新

    2012-01-01

    Objective To evaluate the effect of mitochondrial DNA(mtDNA) secondary mutations,haplotypes,GJB2 gene mutations on phenotype of 1494C > T mutation,and to study the molecular pathogenic mechanism of maternally transmitted aminoglycoside-induced and nonsyndromic hearing loss.Methods Two Chinese Han pedigrees of maternally transmitted aminoglycoside induced and nonsyndromic hearing loss were collected.The two probands and their family members underwent clinical,genetic and molecular evaluations including audiological examinations and mutational analysis of mitochondrial genome and GJB2 gene.Results Clinical evaluation revealed wide range of severity,age-at-onset and audiometric configuration of hearing impairment in matrilineal relatives in both families,for which the penetrance of hearing loss was respectively 42.9 % and 28.6% when aminoglycoside-induced deafness was included.When the effect of aminoglycosides was excluded,the penetrances of hearing loss were 14.3% and 14.3%.Sequence analysis of mitochondrial genomes identified a known 12S rRNA 1494C>T mutation,in addition with distinct sets of mtDNA polymorphisms belonging to Eastern Asian haplogroups C4a1a and B4b1c,respectively.Conclusion Mitochondrial 12S rRNA 1494C>T mutation probably underlie the deafness in both families.Lack of significant mutation in the GJB2 gene ruled out involvement of GJB2 in the phenotypic expression.However,aminoglycosides and other nuclear modifier genes may still modify the phenotype of the 1494C>T mutation in these families.The B4b1c is a newly identified haplogroup in aminoglycoside-induced and nonsyndromic hearing loss family carrying the 1494C>T mutation.The 1494C>T mutation seems to have occurred sporadically through evolution.

  1. Diversity of enterococcal species and characterization of high-level aminoglycoside resistant enterococci of samples of wastewater and surface water in Tunisia.

    Science.gov (United States)

    Ben Said, Leila; Klibi, Naouel; Lozano, Carmen; Dziri, Raoudha; Ben Slama, Karim; Boudabous, Abdellatif; Torres, Carmen

    2015-10-15

    One hundred-fourteen samples of wastewater (n=64) and surface-water (n=50) were inoculated in Slanetz-Bartley agar plates supplemented or not with gentamicin (SB-Gen and SB plates, respectively) for enterococci recovery. Enterococci were obtained from 75% of tested samples in SB media (72% in wastewater; 78% in surface-water), and 85 enterococcal isolates (one/positive-sample) were obtained. Enterococcus faecium was the most prevalent species (63.5%), followed by Enterococcus faecalis (20%), Enterococcus hirae (9.4%), Enterococcus casseliflavus (4.7%), and Enterococcus gallinarum/Enterococcus durans (2.4%). Antibiotic resistance detected among these enterococci was as follows [percentage/detected gene (number isolates)]: kanamycin [29%/aph(3')-IIIa (n=22)], streptomycin [8%/ant(6)-Ia (n=4)], erythromycin [44%/erm(B) (n=34)], tetracycline [18%/tet(M) (n=6)/tet(M)-tet(L) (n=9)], chloramphenicol [2%/cat(A) (n=1)], ciprofloxacin [7%] and trimethoprim-sulfamethoxazole [94%]. High-level-gentamicin resistant (HLR-G) enterococci were recovered from 15 samples in SB-Gen or SB plates [12/64 samples of wastewater (19%) and 3/50 samples of surface-water (6%)]; HLR-G isolates were identified as E. faecium (n=7), E. faecalis (n=6), and E. casseliflavus (n=2). These HLR-G enterococci carried the aac(6')-Ie-aph(2")-Ia and erm(B) genes, in addition to aph(3')-IIIa (n=10), ant(6)-Ia (n=9), tet(M) (n=13), tet(L) (n=8) and cat(A) genes (n=2). Three HLR-G enterococci carried the esp virulence gene. Sequence-types detected among HLR-G enterococci were as follows: E. faecalis (ST480, ST314, ST202, ST55, and the new ones ST531 and ST532) and E. faecium (ST327, ST12, ST296, and the new ones ST985 and ST986). Thirty-two different PFGE patterns were detected among 36 high-level-aminoglycoside-resistant enterococci recovered in water samples. Diverse genetic lineages of HLR-G enterococci were detected in wastewater and surface-water in Tunisia. Water can represent an important source for the

  2. Aminoglycoside trough levels in neonates

    Directory of Open Access Journals (Sweden)

    Pejović Biljana

    2010-01-01

    Full Text Available Introduction. Drug safety depends on trough levels. Objective. Objective of the study was to measure gentamicin and amikacin trough levels in neonates and to identify risk groups by gestational and postnatal age. Methods. Gentamicin and amikacin were applied according to the clinical practice guidelines. Trough levels (mg/l were deter- mined using fluorescence polarization immunoassay methodology. Target trough levels were <2 mg/l for gentamicin, and <10 mg/l for amikacin. Patients were divided in 3 groups by gestational age: I ≤32, II 33-36, and III ≥37 gestational weeks and, by postnatal age, in 2 groups: ≤7 and >7 days. Results. Out of 163 neonates, 111 were receiving gentamicin and 52 amikacin. Mean amikacin trough level was 7.8±4.8 mg/l and, in group I 10.5±4.9 mg/l, which was above the target range and significantly higher than in group II (LSD, p<0.05. In the amikacin group, 26 patients were 7 and less, and 26 more than 7 days old, without significant differences in trough levels between the groups. In the gentamicin group, 52.3% of neonates had trough values within the target range. Gentamicin trough level in group I was above the trough range, 3.7±1.8, 2.3±1.5 in group II and, 1.8±1.4 mg/l in group III. The difference in trough levels among the groups was highly significant (F=9.015, p<0.001, χ2=17. 576, p<0.001. Further analysis revealed that differences between groups I and II (LSD, p=0.002 and between I and III (LSD, p=0.000 were highly significant. Conclusion. Obtained gentamicin and amikacin trough levels are high. Inverse correlation has been confirmed between trough level and gestational age, with highly significant difference, and the risk group has been identified. There is obviously a need to change the dosing regimen in terms of those with extended intervals, particularly for neonates of the lowest gestational age, along with pharmacokinetic measurements.

  3. Study of aminoglycoside modifying enzyme associated resistance genes in Enterococcus%产氨基糖苷类修饰酶肠球菌临床分离株相关耐药基因的研究

    Institute of Scientific and Technical Information of China (English)

    姚杰; 徐元宏; 王友梅; 刘灿

    2011-01-01

    目的 了解临床分离的肠球菌对高水平氨基糖苷类抗菌药物的耐药情况并对其氨基糖苷类修饰酶基因进行检测.方法 用琼脂稀释法检测112株粪肠球菌和118株屎肠球菌对高浓度庆大霉素(500 μg/ml)和高浓度链霉素(2 000 μg/ml)的最低抑菌浓度,随机选取氨基糖苷类高水平耐药的粪肠球菌和屎肠球菌各48株进行氨基糖苷类修饰酶基因检测,PCR扩增aac(6')/aph(2″)、aph(3')-Ⅲ和ant(6)-Ⅰ基因,并对其进行测序分析.结果 112株粪肠球菌和118株屎肠球菌对高浓度庆大霉素的耐药率分别为53.6%和78.8%,对高浓度链霉素的耐药率分别为39.3%和64.4%,且粪肠球菌与屎肠球菌的耐药率差异有统计学意义(P<0.01).aac(6')/aph(2″)基因阳性分别为38株和45株,占80.2%和93.8%;aph(3')-Ⅲ基因阳性分别为14株和19株,占29.2%和39.6%;ant(6)-Ⅰ基因阳性分别为15株和21株,占31.3%和43.8%.其中同时检测出两种和两种以上氨基糖苷类修饰酶基因的菌株有40株,高达41.7%.结论 氨基糖苷类高水平耐药肠球菌已成为医院感染的重要耐药菌,AAC(6')/APH(2″)酶的产生是肠球菌最为常见的氨基糖苷类耐药机制.%Objective To investigate enterococci isolated from clinical specimens on the high level of aminoglycoside antibiotic resistance and the detection of aminoglycoside modifying enzyme gene. Methods 112 strains of E.faecalis and 118 strains of E. faecium to the high-level gentamicin(500 μg/ml)and high-level of streptomycin (2 000 μg/ml)minimum inhibitory concentration were detected by agar ditution method. The aac (6')/aph (2"),aph(3')-Ⅲ and ant(6)- Ⅰ genes were amplified by PCR. Finally,their genotype were determined by DNA sequencing. Results 112 strains of E. faecalis and 118 strains of E. faecium HLGR rates were 53. 1% and 73.2%, and HLSR rates were 38. 9% and 59. 8%. The drug resistance of the two species to high-level gentamicin and high

  4. The aminoglycoside antibiotic kanamycin damages DNA bases in Escherichia coli: caffeine potentiates the DNA-damaging effects of kanamycin while suppressing cell killing by ciprofloxacin in Escherichia coli and Bacillus anthracis.

    Science.gov (United States)

    Kang, Tina Manzhu; Yuan, Jessica; Nguyen, Angelyn; Becket, Elinne; Yang, Hanjing; Miller, Jeffrey H

    2012-06-01

    The distribution of mutants in the Keio collection of Escherichia coli gene knockout mutants that display increased sensitivity to the aminoglycosides kanamycin and neomycin indicates that damaged bases resulting from antibiotic action can lead to cell death. Strains lacking one of a number of glycosylases (e.g., AlkA, YzaB, Ogt, KsgA) or other specific repair proteins (AlkB, PhrB, SmbC) are more sensitive to these antibiotics. Mutants lacking AlkB display the strongest sensitivity among the glycosylase- or direct lesion removal-deficient strains. This perhaps suggests the involvement of ethenoadenine adducts, resulting from reactive oxygen species and lipid peroxidation, since AlkB removes this lesion. Other sensitivities displayed by mutants lacking UvrA, polymerase V (Pol V), or components of double-strand break repair indicate that kanamycin results in damaged base pairs that need to be removed or replicated past in order to avoid double-strand breaks that saturate the cellular repair capacity. Caffeine enhances the sensitivities of these repair-deficient strains to kanamycin and neomycin. The gene knockout mutants that display increased sensitivity to caffeine (dnaQ, holC, holD, and priA knockout mutants) indicate that caffeine blocks DNA replication, ultimately leading to double-strand breaks that require recombinational repair by functions encoded by recA, recB, and recC, among others. Additionally, caffeine partially protects cells of both Escherichia coli and Bacillus anthracis from killing by the widely used fluoroquinolone antibiotic ciprofloxacin. PMID:22391551

  5. Mitochondrial COX2 G7598A Mutation May Have a Modifying Role in the Phenotypic Manifestation of Aminoglycoside Antibiotic-Induced Deafness Associated with 12S rRNA A1555G Mutation in a Han Chinese Pedigree

    Science.gov (United States)

    Chen, Tianbin; Liu, Qicai; Jiang, Ling; Liu, Can

    2013-01-01

    Recent studies suggest that certain mitochondrial haplogroup markers and some specific variants in mitochondrial haplogroup may also influence the phenotypic expression of particular mitochondrial disorders. In this report, the clinical, genetic, and molecular characterization were identified in a Chinese pedigree with the aminoglycoside antibiotic (AmAn)-induced deafness and nonsyndromic hearing loss (NSHL). The pathogenic gene responsible for this hereditary NSHL pedigree was determined by Microarray chip, which possessed the nine NSHL hot-spot mutations, including GJB2 (35delG, 176dell6bp, 235de1C, and 299delAT), GJB3 (538C>T), SLC26A4 (IVS7-2A>G and 2168A>G), and mitochondrial DNA (mtDNA) 12S rRNA (C1494T and A1555G). Only the homoplasmic A1555G mutation was detected, which was confirmed by direct sequencing. Also, real-time amplification refractory mutation system quantitative polymerase chain reaction methodology was performed to calculate the A1555G mutation load. The proband's complete mtDNA genome were amplified and direct sequencing was performed to determine the mitochondrial haplogroup and private mutations. The proband's mitochondrial haplogroup belonges to M7b1 and a private mutation MTCOX2 G7598A (p.Ala 5 Thr) is found. Phylogenetic analysis of COX2 polypeptide sequences demonstrates that the alanine residue is relatively conserved, but owing to the missense mutation (p.Ala 5 Thr), its side chain hydrophobicity will be changed, and what is more, as it is adjacent to a glutamine residue, which is highly conserved and hydrophilic, in an evolutionary stable domain; G7598A (p.Ala 5 Thr) may alter the protein secondary structure and physiological function of COX2 and, thus, aggravate the mitochondrial dysfunction conferred by the A1555G mutation. Furthermore, the G7598A mutation is absent in 100 unrelated healthy controls; therefore, G7598A (p.Ala 5 Thr) in the mitochondrial haplogoup M7b1 may have a modifying role, enhancing its penetrance and severity

  6. DNA-Aptamers Binding Aminoglycoside Antibiotics

    OpenAIRE

    Nadia Nikolaus; Beate Strehlitz

    2014-01-01

    Aptamers are short, single stranded DNA or RNA oligonucleotides that are able to bind specifically and with high affinity to their non-nucleic acid target molecules. This binding reaction enables their application as biorecognition elements in biosensors and assays. As antibiotic residues pose a problem contributing to the emergence of antibiotic-resistant pathogens and thereby reducing the effectiveness of the drug to fight human infections, we selected aptamers targeted against the aminog...

  7. Damaging Effects of Aminoglycoside Antibiotics on Cochlear Spiral Ganglion Neurons%氨基糖苷类抗生素对耳蜗螺旋神经节的损害作用

    Institute of Scientific and Technical Information of China (English)

    高可雷; 丁大连; 李鹏; 孙虹; Richard Salvi

    2015-01-01

    氨基糖苷类药物(AmAn)是一类经典的治疗革兰阴性菌感染的抗生素,但具有耳毒性和肾毒性。以往的研究认为AmAn的耳毒性仅仅针对内耳毛细胞并可引起继发的延迟性螺旋神经节细胞(SGNs)死亡。但是随着关于AmAn耳毒性和对耳蜗其他细胞的研究进展,人们逐渐意识到耳蜗内支持细胞的损害也是引起SGNs延迟死亡的重要原因之一。我们发现,不同的AmAn对内耳的损害方式不同,以硫酸链霉素为代表的少数AmAn可以不受血-迷路屏障阻碍直接进入内耳并首先损害内耳的周边神经元;而以往认为只能间接损害SGNs的其他那些难以跨越血-迷路屏障的AmAn,比如卡那霉素,对出生后三天大鼠处于发育阶段的SGNs也具有直接的损害作用。因此我们提出一个根据不同内耳损害方式来区分AmAn的分类建议,并希望本文介绍的新内容能够为更深入理解不同种类AmAn的不同耳毒性机制以及听觉系统各个重要组织成分之间的相互作用关系提供新的参考信息。%Aminoglycoside antibiotics (AmAn) are widely used for gram negative bacterial infections while they are al⁃so notorious for their ototoxicity and nephrotoxicity. Conventional view is that the ototoxic effects of AmAn can only damage sensory hair cells in the inner ear, and can cause delayed spiral ganglion neurons (SGNs) degeneration as a result of the loss of sensory hair cells. But with deepening of research, people have come to realize that supporting cell damage is also one of the important reasons for the delayed SGNs death. Meanwhile, it has been found that different AmAns may exert their ototoxic ef⁃fects through different approaches to different target cells via different pathways. Streptomycin sulfate, which represents a mi⁃nor category of AmAn, passes easily through the blood-labyrinth barrier and can directly damage peripheral neurons in the in⁃ner ear. AmAns that

  8. 核修饰基因与氨基糖甙类药物在母系遗传性聋发病机制及功能研究%Mechanism and Functional Research on Nuclear Modified Gene Associated with Maternally Inherited Aminoglycoside-Induced Deafness

    Institute of Scientific and Technical Information of China (English)

    刘日渊; 刘琪; 郝青青; 董思琪; 徐广雨; 赵辉

    2013-01-01

    Objective To study the molecular genetics and cell functions of non-sensitivity to aminoglycosides and to an-alyze the molecular mechanism in a family with maternally transmitted aminoglycoside-induced non-syndromic deafness. Methods A clinical,molecular,genetic and phylogenic analysis in this Chinese family was performed. Results Sequence analy-sis of mitochondrial DNA in this pedigree identified a homoplastic A-to-G transition at position 1555 (A1555G) in the 12S rRNA gene. Analysis of the complete mtDNA genome revealed that this family belonged to haplotype D5b1b and exhibited high penetrance in contrast with other reported families. There was a variation found in the MTO1 gene: 74202000_74202001insG and 74202003delG, indicating that the MTO1 gene may be the nuclear modified gene in this family. There was no significant mutation in the TRMU gene. Exposure to a high concentration of aminoglycosides caused an increase in dou-bling time in lymphoblastoid cell lines derived from one symptomatic individual in this family, while the doubling time of the cell lines from the asymptomatic individual didn’t increase. Conclusion These results suggest that the nuclear background plays a role in the aminoglycoside ototoxicity and in the development of the deafness phenotype associated with the A1555G mutation in the mitochondrial 12S rRNA gene.%目的对同时存在线粒体DNA 12S rRNA基因突变(A1555G突变)和存在个体表现出对氨基糖甙类药物不敏感的家系进行系统的资料收集和分子机制分析工作。方法对此家系进行体格检查、耳鼻咽喉专科检查、听力学检查,并对此家系进行线粒体DNA测定、线粒体单体型分型、氨基糖甙类药物敏感性检测、线粒体DNA相关核修饰基因TRMU和MTO1等研究。结果通过对全体成员的线粒体DNA序列测序分析,该家系的母系成员均有同质性A1555G突变;线粒体单体型分析为D5b1b;对发现的氨基糖甙类药物不敏感

  9. 耐药大肠埃希菌β-内酰胺类、氨基糖苷类获得性耐药基因与可移动遗传元件研究%Investigation of acquired resistance genes to β-lactams, aminoglycosides and mobile genetic elements in multidrug-resistant Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    张建明; 万长标; 钱玮和; 程建平; 金跃

    2011-01-01

    目的 调查多药耐药大肠埃希菌β-内酰胺类、氨基糖苷类获得性耐药基因与可移动遗传元件的存在情况.方法 收集医院2007年1-12月患者标本中分离的20株多药耐药大肠埃希菌,采用聚合酶链反应(PCR)的方法,分析42种β-内酰胺类、氨基糖苷类获得性耐药基因以及10种可移动遗传元件的遗传标记;并对上述检测结果做样本聚类分析.结果20 株多药耐药大肠埃希菌检出β-内酰胺类获得性耐药基因TEM-1及CTX-M-55,检出率为80.0%、50.0%,氨基糖苷类获得性耐药基因aac(3)-Ⅱ、aac(6’)-Ⅰb、ant(3")-Ⅰ、aadA5、aph(3’)-Ⅰ,检出率分别为45.0%、5.0%、10.0%、45.0%、5.0%,可移动遗传元件检出intⅠ 1、tnp513、IS26、ISEcp1、traA、trbC,检出率分别为55.0%、25.0%、90.0%、65.0%、80.0%、75.0%;其他39种基因未检出.结论 20株多药耐药大肠埃希菌耐β-内酰胺类、氨基糖苷类药物与细菌产2种β-内酰胺类获得性耐药基因、5种氨基糖苷类获得性耐药基因相关;可移动遗传元件的水平转移使细菌的耐药性在同种细菌菌株之间甚至不同种细菌菌株之间得以快速传播;样本聚类分析提示,该组多药耐药大肠埃希菌尚无克隆传播.%OBJECTIVE To investigate the distribution of acquired resistance genes to [3-lactams, aminoglycosides and mobile genetic elements in multidrug-resistant Escherichia coli (E. Coli). METHODS From Jan 2007 to Dec 2007, 20 strains of E. Coli were collected from The Second People's Hospital of Huaian. Then, 42 kinds of acquired resistance genes to β-lactams, aminoglycosides and 10 kinds of genetic markers of mobile genetic elements were analyzed by PCR. In addition, sample cluster analysis was performed. RESULTS In 20 strains of multidrug-resistant E. Coli, acquired resistance genes to β-actams: TEM-1, CTX-M-55, acquired resistance genes to aminoglycosides! Aac(3)-II , aac(6')-I b, ant(3")-I

  10. Maternally inherited aminoglycoside-induced and nonsyndromic hearing loss in five Han Chinese pedigrees*%五个母系遗传非综合征性耳聋和药物性耳聋的中国汉族家系

    Institute of Scientific and Technical Information of China (English)

    张婷; 陈波蓓; 郑静; 龚莎莎; 张初琴; 吕建新; 管敏鑫

    2011-01-01

    目的 通过对母系遗传非综合征性耳聋家系临床和分子遗传学特征分析,进一步探讨线粒体12S rRNA基因对母系遗传药物性耳聋的影响.方法 收集5个非综合征性耳聋患者家系,提取基因组DNA,然后进行线粒体DNA全序列和间隙连接蛋白β2(gap junction protein beta 2,GJB2)基因扩增并测序分析.结果 5个家系内和家系间的母系成员在听力损失、发病年龄和听力曲线上存在较大差异.5个家系耳聋发生的外显率分别为17.6%、50.0%、66.7%、31.3%和23.1%,平均外显率是37.7%.线粒体全序列显示家系间存在已知的1555A>G突变和不同的多态性位点,分别属于东亚人群D4b2b、B4c1b1、F3、C1、D5a单倍型.这5个家系没有携带已知的线粒体DNA继发突变,但发现了2个保守性较高的ND1L89T和CO3 A200T突变.而且,GJB2基因上未发现与耳聋相关的突变.结论 这5个母系遗传非综合征性耳聋家系中,线粒体DNA继发突变、GJB2基因可能没有影响1555A>G的表型表达.然而,氨基糖甙类抗生素、线粒体DNA多态性及其他核修饰基因可能对这5个耳聋家系的表型表达起到修饰作用.%Objective To study the effect of the mitochondrial 12S rRNA mutations on aminoglycoside-induced and nonsyndromic hearing loss, to carry out the clinical and molecular characterization of five Han Chinese pedigrees with maternally transmitted aminoglycoside-induced and nonsyndromic hearing loss. Methods Five pedigrees of maternally transmitted aminoglycoside-induced and nonsyndromic hearing loss were collected, genomic DNA was extracted, and complete mitochondrial genomes and the gap junction protein, beta 2 (GJB2) gene were amplified and sequenced. Results Clinical evaluation revealed a wide range of severity, age-at-onset and audiometric configuration of hearing impairment in the matrilineal relatives in these families. The penetrance rates of hearing loss in these pedigrees were 17. 6%, 50. 0%, 66. 7

  11. Heteroplasmy Levels of Mitochondrial 12S rRNA A1555G Mutation in Pedigrees with Aminoglycoside-Induced and Non-Syndromic Hearing Loss as Detected Using SNaPshot Technique%线粒体12SrRNAA1555G突变耳聋家系的异质率研究

    Institute of Scientific and Technical Information of China (English)

    朱玉华; 翟所强; 戴朴

    2014-01-01

    Objective To study heteroplasmy levels and inheritance patterns of the mitochondrial 12S rRNA A1555G mutation in a K-11 pedigree with aminoglycoside-induced and non-syndromic hearing loss using the SNaPshot technique. Methods Comprehensive history and physical examination were obtained, including history of aminoglycoside use and genetic factors related to the hearing impairment among the pedigree members. Age-appropriate audiological tests were performed and the PTA calculated. Genomic DNA was isolated from whole blood and the level of heteroplasmy in peripheral blood leuko-cytes was determined using SNaPshot technology. Results There were four generations in this K-11 pedigree. Deafness was the only clinical phenotype. The onset age and extent of hearing loss were different among maternal members. The average het-eroplasmy rate of this K-11 pedigree was 87.99%(ranging from 82.32%to 94.65%), and the average heteroplasmy rates of generations II to IV were 88.27%, 86.78%, and 90.31%, respectively. Conclusion There are random shifts in the heteroplasmy level between mothers and offspring with the A1555G mutation in K-11 pedigrees. However, there seems a trend of gradual increase over generations.%目的:利用SNaPshot技术检测线粒体12S rRNA A1555G异质性突变耳聋家系(K-11)母系成员的突变异质率,探讨家系中异质率的分布状况和遗传规律。方法通过家系调查,对线粒体12S rRNA A1555G异质性突变耳聋家系母系成员进行全身系统检查及临床听力学检测;提取基因组和线粒体DNA,针对12S rRNA A1555G突变,设计SnaPshot引物和探针,并对K-11家系母系成员进行异质率检测,分析K-11家系母系成员突变异质率的分布特点和遗传规律。结果 K-11家系共四代,耳聋是此家系的唯一临床表型,家系母系耳聋成员的听力下降时间、程度和听力曲线类型具有明显的个体差异;家系中每位家系母系成员的12S rRNA A1555G突变

  12. 糖尿病足分离的铜绿假单胞菌对氨基糖苷类抗生素耐药机制探讨%Study on aminoglycoside antibiotics resistance of Pseudomonas aeruginosa isolated from diabetic foot infections

    Institute of Scientific and Technical Information of China (English)

    乌洪芳; 孙茜; 李玉珠; 张敏; 孟玲玲; 李代清

    2015-01-01

    Objective To investigate the clinical features, phenotypes and genotypes of Pseudomonas aeruginosa (PA) strains isolated from patients with diabetic foot infection (DFI) resisting to aminoglycosides antibiotics (AmAn). Methods The clinical profiles of 209 DFI patients hospitalized in the Tianjin Metabolic Diseases Hospital were collected and ana⁃lyzed. Forty-one PA strains were identified, and their antibiotic resistance profiles were obtained. The DNAs of PA isolates were extracted and applied to amplifications for several aminoglycosides modifying enzyme genes, including aac(3′)-Ⅰ, aac (3′)-Ⅱ, aac(6′)-Ⅰb, aac(6′)-Ⅱ, ant(2′′)-Ⅰand ant(3′′)-Ⅰby PCR method. Combining with the clinical features and the antibiotic resistance profiles, the relationship between genotypes and phenotypes of the PA strains was analyzed. Results Gram positive bacteria (G+) were the majority of the pathogen with 51.67%detection rate. The total detection rate of PA was 19.62%, listed as the top one pathogenic bacterium among gram negative bacteria (47.67%). There was significant difference in the ratio of ulcer area≥4 cm2 between PA group and non-PA group and G+group. There were significantly higher inci⁃dence rate of ischemic ulcer and osteomyelitis in PA group than those of G+group. There were higher clinical characteristics and ulcer depth (SAD) score, and increased hypersensitive C-reactive protein in PA group than those of G+ group. There were 30 strains of PA being resistant to AmAn (73.17%). The predominant drug resistance gene to AmAn was ant(3′′)-Ⅰ(65.85%), and aac(3′)-Ⅰgene was not found from all PA isolates. Conclusion The detection rate of PA isolated from DFI patients was higher, and patients were with the characteristics of larger, deeper and severe ischemia of ulcer area. The phe⁃nomenon of PA resistant to AmAn was more serious, and ant(3′′)-Ⅰgene identified from PA isolates was the most common resistance gene identified to Am

  13. Influencing uptake and localization of aminoglycoside-functionalized peptoids.

    Science.gov (United States)

    Lee, Melissa M; French, Jonathan M; Disney, Matthew D

    2011-08-01

    The development of small-molecule therapeutics that target RNA remains a promising field but one hampered with considerable challenges that include programming high affinity, specificity, cell permeability, and favorable pharmacokinetic profiles. Previously, we employed the use of peptoids to modularly display RNA-binding modules to enhance binding affinity and specificity by altering valency and the distance between ligand modules. Herein, factors that affect uptake, localization, and toxicity of peptoids that display a kanamycin derivative into a variety of mammalian cells lines are reported. A series of peptoids that display various spacing modules was synthesized to determine if the spacing module affects permeability and localization. The spacing module does affect cellular permeability into C2C12, A549, HeLa, and MCF7 cell lines but not into Jurkat cells. Moreover, the modularly assembled peptoids carrying the kanamycin cargo localize in the cytoplasm and perinuclear region of C2C12 and A549 cells and throughout HeLa cells, including the nucleus. These studies could contribute to the development of general strategies to afford cell permeable, modularly assembled small molecules that specifically target RNAs present in a variety of cell types. PMID:21611644

  14. Influencing uptake and localization of aminoglycoside-functionalized peptoids†

    OpenAIRE

    Lee, Melissa M.; French, Jonathan M.; Disney, Matthew D.

    2011-01-01

    The development of small-molecule therapeutics that target RNA remains a promising field but one hampered with considerable challenges that include programming high affinity, specificity, cell permeability, and favorable pharmacokinetic profiles. Previously, we employed the use of peptoids to modularly display RNA-binding modules to enhance binding affinity and specificity by altering valency and the distance between ligand modules. Herein, factors that affect uptake, localization, and toxici...

  15. USMB-induced synergistic enhancement of aminoglycoside antibiotics in biofilms.

    Science.gov (United States)

    Ronan, Evan; Edjiu, Narbeh; Kroukamp, Otini; Wolfaardt, Gideon; Karshafian, Raffi

    2016-07-01

    This study evaluated the effect of combining antibiotics with ultrasound and microbubbles (USMB) toward the eradication of biofilms. Pseudomonas aeruginosa PAO1 biofilms were treated with the antibiotics gentamicin sulfate or streptomycin sulfate, or a combination of USMB with the respective antibiotics. Biofilm structure was quantified using confocal laser scanning microscopy with COMSTAT analysis, while activity was measured as whole-biofilm CO2 production in a continuous-flow biofilm model. The combined antibiotic-USMB treatment significantly impacted biofilm biomass, thickness and surface roughness compared to antibiotics alone (p<0.05). USMB exposure caused the formation of craters (5-20μm in diameter) in the biofilms, and when combined with gentamicin, activity was significantly lower, compared to gentamicin, USMB or untreated controls, respectively. Interestingly, the CO2 production rate following combined streptomycin-USMB treatment was higher than after streptomycin alone, but significantly lower than USMB alone and untreated control. These results show strong evidence of a synergistic effect between antibiotics and USMB, although the varied response to different antibiotics emphasize the need to optimize the USMB exposure conditions to maximize this synergism and ultimately transfer this technology into clinical or industrial practice. PMID:27111871

  16. Molecular genetic characterization of two pedigrees with mitochondrial 12S rRNA C1494T mutation and aminoglycoside-induced hearing loss%两个线粒体12S rRNA C1494T突变及药物性耳聋家系的分子遗传学研究

    Institute of Scientific and Technical Information of China (English)

    李海峰; 陈智斌; 邢光前

    2011-01-01

    目的:探讨2个氨基糖甙类药物性耳聋及非综合征型耳聋家系的分子遗传学特征.方法:收集家系成员外周血样,常规方法提取基因组DNA.首先,利用基因芯片对中国人4个常见耳聋基因的9个突变热点进行分子筛查,9个位点分别为:CJB2基因的35 delG、176 de116、235 delC和299 delAT;GJB3基因的538 C>T;PDS基因的IVS7-2 A>G和2168 A>G以及mtDNA 12S rRNA基因的1494 C>T和1555 A>G.然后,对两家系的先证者分别进行线粒体DNA全序列及核基因TRMU和MTO1编码区的PCR扩增和测序分析.结果:芯片检测发现两家系的7名母系成员均存在同质性mtDNA 12S rRNA C1494T突变.与修正的剑桥参考序列相比,2名先证者的mtDNA全序列分析共检测到53个碱基变异,但除已知的12S rRNA C1494T突变外,其余52个碱基变异均为已报道的多态性位点;两家系先证者线粒体单体型分别是D4和D5a;TRMU和MTO1基因序列分析无异常发现.结论:线粒体DNA 12SrRNA C1494T突变是两个家系耳聋发生的主要分子基础,而氨基糖甙类抗生素的应用增强了该突变的表型表达:未能证实线粒体单体型以及核基因TRMU和MTO1对家系成员C1494T突变的表型具有修饰作用.%Objective:To explore the molecular genetic characterization of two families with aminoglycoside-induced and nonsyndromie sensofineural hearing loss. Methods:Blood samples were obtained from 7 maternal members and I married-in spouse of the two families. Genomic DNA was extracted with conventional method. Firstly, 9 hot spots for mutations in four most common pathologic genes, GJB2, GJB3, SLC26A4 and mitochondrial 12S rRNA, were screened with the DNA mieroarray to detect the deafness-associated mutations. The whole mitochondrial genomes and nuclear modifier genes TRMU and MTO1 of two probands were then PCR amplified and submitted for sequence analysis. Results:Mitochondrial 12S rRNA C1494T mutation was detected in all 7 maternal members of

  17. Sublethal Triclosan Exposure Decreases Susceptibility to Gentamicin and Other Aminoglycosides in Listeria monocytogenes

    DEFF Research Database (Denmark)

    Christensen, Ellen Gerd; Gram, Lone; Kastbjerg, Vicky Gaedt

    2011-01-01

    The human food-borne pathogen Listeria monocytogenes is capable of persisting in food processing plants despite cleaning and sanitation and is likely exposed to sublethal biocide concentrations. This could potentially affect susceptibility of the bacterium to biocides and other antimicrobial agents...... Super (containing quaternary ammonium compound) in four consecutive cultures did not alter the frequency of antibiotic-tolerant isolates, as determined by plating on 2x the MIC for a range of antibiotics. Exposure of eight strains of L. monocytogenes to 1 and 4 µg/ml triclosan did not alter triclosan...

  18. Tolerance of Norway spruce (Picea abies [L.] Karst.) embryogenic tissue to penicillin, carbapenem and aminoglycoside antibiotics

    Czech Academy of Sciences Publication Activity Database

    Malá, J.; Pavingerová, Daniela; Cvrčková, H.; Bříza, Jindřich; Dostál, J.; Šíma, P.

    2009-01-01

    Roč. 55, č. 4 (2009), s. 156-161. ISSN 1212-4834 R&D Projects: GA MZe QH71290 Institutional research plan: CEZ:AV0Z50510513 Keywords : somatic embryogenesis * Norway spruce * penicillin antibiotics * Agrobacterium tumefaciens * carbapenem antibiotics Subject RIV: EB - Genetics ; Molecular Biology

  19. Study of the Interference between Plectranthus Species Essential Oils from Brazil and Aminoglycosides

    OpenAIRE

    Fabíola Fernandes Galvão Rodrigues; José Galberto Martins Costa; Fábio Fernandes Galvao Rodrigues; Adriana Rolim Campos

    2013-01-01

    Plectranthus is one of the most representative genera of Lamiaceae family. In this study, the essential oils from Plectranthus amboinicus, Plectranthus ornatus, and Plectranthus barbatus were investigated for their chemical composition and antimicrobial and modulatory activities. The major components found were carvacrol (54.4%—P. amboinicus) and eugenol (22.9%—P. ornatus e 25.1%—P. barbatus). In vitro antimicrobial activity was conducted against Escherichia coli, Proteus vulgaris, Bacillus c...

  20. Aminoglycoside-induced mutation suppression (stop codon readthrough) as a therapeutic strategy for Duchenne muscular dystrophy

    OpenAIRE

    Malik, Vinod; Rodino-Klapac, Louise R.; Viollet, Laurence; Mendell, Jerry R.

    2010-01-01

    Duchenne muscular dystrophy (DMD) is the most common, lethal, X-linked genetic disease, affecting 1 in 3500 newborn males. It is caused by mutations in the DMD gene. Owing to the large size of the gene, the mutation rate in both germline and somatic cells is very high. Nearly 13–15% of DMD cases are caused by nonsense mutations leading to premature termination codons in the reading frame that results in truncated dystrophin protein. Currently there is no cure for DMD. The only available treat...

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

    OpenAIRE

    Felipe S. Ferreira; Nalba L. G. Silva; Edinardo F.F Matias; Samuel V. Brito; Francisco G. Oliveira; José G. M. Costa; Coutinho, Henrique D. M.; Waltécio O. Almeida; Alves, Rômulo R. N.

    2011-01-01

    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 rem...

  2. Spectrophotometric Determination of Aminoglycoside Antibiotics Based on their Oxidation by Potassium Permanganate

    International Nuclear Information System (INIS)

    A rapid, simple and sensitive validated spectrophotometric methods have been described for the assay of neomycin and streptomycin either in pure form or in pharmaceutical formulations. The proposed methods were based on the oxidation of the studied drugs by a known excess of potassium permanganate in acidic medium and estimating the unreacted permanganate with amaranth dye (method A), acid orange II (method B), indigocarmine (method C), and methylene blue (method D), in the same acid medium at a suitable λmax=521, 485, 610 and 664 nm, respectively. Beer's law is obeyed in the concentration range of 5-10 and 2-7 mg mL-1 for neomycin and streptomycin, respectively. The apparent molar absorptivity and sandell sensitivity values are in the range 5.47-6.20x104, 2.35-2.91x105 L mol-1 cm-1 and 7.57-8.59, 5.01-6.2 ng cm-2 for neomycin and streptomycin, respectively. Different variables affecting the reaction were studied and optimized. The proposed methods were applied successfully to the determination of the examined drugs either in a pure or pharmaceutical dosage forms with good accuracy and precision. No interferences were observed from excipients and the results obtained were in good agreement with those obtained using the official methods

  3. Comparative Study of Erythrocyte Sedimentation Rate after Aminoglycoside and Aminocyclitol Treatment in Goats (Capra hircus)

    OpenAIRE

    DINEV, Toncho; KANAKOV, Dian; Georgi BEEV; Rusenova, Nikolina; Stefan DENEV

    2016-01-01

    The aim of the present study was to follow up the erythrocyte sedimentation rate (ESR) in healthy female goats during and after 5-day parenteral treatment with amikacin (10 mg/kg), tobramycin (5 mg/kg), apramycin (20 mg/kg), gentamicin (4 mg/kg), kanamycin (10 mg/kg) and spectinomycin (20 mg/kg). Gentamicin and tobramycin caused an initial increase followed by a significant decrease of ESR on the 5th day for gentamicin and the 10th day for tobramycin, respectively, followed by recovery after ...

  4. Sublethal Triclosan Exposure Decreases Susceptibility to Gentamicin and Other Aminoglycosides in Listeria monocytogenes▿

    OpenAIRE

    Christensen, Ellen G.; Gram, Lone; Kastbjerg, Vicky G.

    2011-01-01

    The human food-borne pathogen Listeria monocytogenes is capable of persisting in food processing plants despite cleaning and sanitation and is likely exposed to sublethal biocide concentrations. This could potentially affect susceptibility of the bacterium to biocides and other antimicrobial agents. The purpose of the present study was to determine if sublethal biocide concentrations affected antibiotic susceptibility in L. monocytogenes. Exposure of L. monocytogenes strains EGD and N53-1 to ...

  5. A nanoplex PCR assay for the rapid detection of vancomycin and bifunctional aminoglycoside resistance genes in Enterococcus species

    OpenAIRE

    Ravichandran Manickam; Lalitha Pattabhiraman; Yin Lee; Yean Chan

    2007-01-01

    Abstract Background Enterococci have emerged as a significant cause of nosocomial infections in many parts of the world over the last decade. The most common enterococci strains present in clinical isolates are E. faecalis and E. faecium which have acquired resistant to either gentamicin or vancomycin. The conventional culture test takes 2–5 days to yield complete information of the organism and its antibiotic sensitivity pattern. Hence our present study was focused on developing a nanoplex P...

  6. Development of aminoglycoside and β-lactamase resistance among intestinal microbiota of swine treated with lincomycin, chlortetracycline, and amoxicillin

    OpenAIRE

    Sun, Jian; Liang LI; Liu, Baotao; Xia, Jing; Liao, Xiaoping; Liu, Yahong

    2014-01-01

    Lincomycin, chlortetracycline, and amoxicillin are commonly used antimicrobials for growth promotion and infectious disease prophylaxis in swine production. In this study, we investigated the shifts and resistance development among intestinal microbiota in pregnant sows before and after lincomycin, chlortetracycline, and amoxicillin treatment by using phylogenetic analysis, bacterial enumeration, and PCR. After the antimicrobial treatment, shifts in microbial community, an increased proportio...

  7. Assessment of hearing loss in multi-drug resistant tuberculosis (MDR-TB) patients undergoing Aminoglycoside treatment

    OpenAIRE

    Sheikh Nizamuddin; Farhan Ahmad Khan; Abdur Rehman Khan; Chand Miyan Kamaal

    2015-01-01

    Background: Incomplete treatments and treatment failures has led to Multi-drug resistant tuberculosis, which has emerged as a significant problem in treating tuberculosis and thus the second line drugs are used with the concomitant increase in the incidence of adverse effects. Methods: This prospective study was carried out from June 2009 to May 2014 in the department of ENT in collaboration with TB and Chest at Teerthanker Mahaveer Medical College and Research Centre. Out of 104, ...

  8. Minimum inhibitory concentration values and problematic disk break points of tigecycline against vancomycin and/or high-level aminoglycoside-resistant enterococci

    OpenAIRE

    Latife İşeri; Esra Şahin; İştar Dolapçı; Zehra Yürüken

    2016-01-01

    Background: Tigecycline is a new, semisynthetic glycylcycline. It is active against important multidrug resistant pathogens. Aim: The purpose of this study was to investigate the sensitivity of multidrug-resistant enterococci to tigecycline, and to test the correlation between the minimal inhibitory concentration (MIC) and disk diffusion methods. Materials and methods: The antimicrobial sensitivity of 108 multidrug-resistant isolates, which included 52 vancomycin-resistant enterococci (...

  9. Multiple ESBL-producing Escherichia coli sequence types carrying quinolone and aminoglycoside resistance genes circulating in companion and domestic farm animals in Mwanza, Tanzania, harbor commonly occurring plasmids

    Directory of Open Access Journals (Sweden)

    Jeremiah eSeni

    2016-02-01

    Full Text Available The increased presence of extended-spectrum beta-lactamase (ESBL-producing bacteria in humans, animals and their surrounding environments is of global concern. Currently there is limited information on ESBL presence in rural farming communities worldwide. We performed a cross-sectional study in Mwanza, Tanzania, involving 600 companion and domestic farm animals between August/September 2014. Rectal swab/cloaca specimens were processed to identify ESBL-producing Enterobacteriaceae. We detected 130 (21.7% animals carrying ESBL-producing bacteria, the highest carriage being among dogs and pigs [39.2% (51/130 and 33.1% (43/130, respectively]. The majority of isolates were Escherichia coli [93.3% (125/134] and exotic breed type [OR (95%CI = 2.372 (1.460 - 3.854, p-value <0.001] was found to be a predictor of ESBL carriage among animals. Whole-genome sequences of 25 ESBL-producing E. coli were analyzed for phylogenetic relationships using multi-locus sequence typing (MLST and core genome comparisons. Fourteen different sequence types were detected of which ST617 (7/25, ST2852 (3/25, ST1303 (3/25 were the most abundant. All isolates harbored the blaCTX-M-15 allele, 22/25 carried strA and strB, 12/25 aac(6’Ib-cr and 11/25 qnrS1. Antibiotic resistance was associated with IncF, IncY, as well as non-typable plasmids. Eleven isolates carried pPGRT46-related plasmids, previously reported from isolates in Nigeria. Five isolates had plasmids exhibiting 85-99% homology to pCA28, previously detected in isolates from the United States. Our findings indicate a pan-species distribution of ESBL-producing E. coli clonal groups in farming communities and provide evidence for plasmids harboring antibiotic resistances of regional and international impact.

  10. Multiple ESBL-Producing Escherichia coli Sequence Types Carrying Quinolone and Aminoglycoside Resistance Genes Circulating in Companion and Domestic Farm Animals in Mwanza, Tanzania, Harbor Commonly Occurring Plasmids.

    Science.gov (United States)

    Seni, Jeremiah; Falgenhauer, Linda; Simeo, Nabina; Mirambo, Mariam M; Imirzalioglu, Can; Matee, Mecky; Rweyemamu, Mark; Chakraborty, Trinad; Mshana, Stephen E

    2016-01-01

    The increased presence of extended-spectrum beta-lactamase (ESBL)-producing bacteria in humans, animals, and their surrounding environments is of global concern. Currently there is limited information on ESBL presence in rural farming communities worldwide. We performed a cross-sectional study in Mwanza, Tanzania, involving 600 companion and domestic farm animals between August/September 2014. Rectal swab/cloaca specimens were processed to identify ESBL-producing Enterobacteriaceae. We detected 130 (21.7%) animals carrying ESBL-producing bacteria, the highest carriage being among dogs and pigs [39.2% (51/130) and 33.1% (43/130), respectively]. The majority of isolates were Escherichia coli [93.3% (125/134)] and exotic breed type [OR (95%CI) = 2.372 (1.460-3.854), p-value animals. Whole-genome sequences of 25 ESBL-producing E. coli were analyzed for phylogenetic relationships using multi-locus sequence typing (MLST) and core genome comparisons. Fourteen different sequence types were detected of which ST617 (7/25), ST2852 (3/25), ST1303 (3/25) were the most abundant. All isolates harbored the bla CTX-M-15 allele, 22/25 carried strA and strB, 12/25 aac(6')-lb-cr, and 11/25 qnrS1. Antibiotic resistance was associated with IncF, IncY, as well as non-typable plasmids. Eleven isolates carried pPGRT46-related plasmids, previously reported from isolates in Nigeria. Five isolates had plasmids exhibiting 85-99% homology to pCA28, previously detected in isolates from the US. Our findings indicate a pan-species distribution of ESBL-producing E. coli clonal groups in farming communities and provide evidence for plasmids harboring antibiotic resistances of regional and international impact. PMID:26904015

  11. Characterization of Resistance to Aminoglycosides in Methicillin-Resistant Staphylococcus aureus Strains Isolated From a Tertiary Care Hospital in Tehran, Iran

    OpenAIRE

    Rahimi, Fateh

    2016-01-01

    Background: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common nosocomial pathogens which can cause a broad spectrum of infections. Objectives: The current study aimed to describe the frequency and antibiotic susceptibility patterns of clonal groups of gentamicin-resistant strains of MRSA isolated from a tertiary care hospital in Tehran, Iran. Materials and Methods: A total of 301 S. aureus isolates were collected during January to November 2012. All of the isolates ...

  12. An usual approach to treatment of a case of multidrug resistance Pseudomonas aeruginosa peritonitis: parenteral and intraperitoneal aminoglycosides and parenteral colistin

    Directory of Open Access Journals (Sweden)

    Ian May

    2012-09-01

    Full Text Available Infections caused by Pseudomonas aeruginosa are becoming more common and increasingly more difficult to treat due to the continued development of drug resistance. While sensitivity to colistin (polymyxin E is well known, it is frequently avoided due to concerns of nephrotoxicity. Reported here is a case of a multi-drug resistance pseudomonal typhlitis, bacteremia and pleural cavity infection that required significant intensive care, and serial abdominal washouts. Intra-peritoneal tobramycin in combination with broad-spectrum intravenous antibiotics including colistin were used. Several instillations of tobramycin into the abdominal cavity along with concomitant IV administration of colistin, ceftazidime and tobramycin and per os colistin, tobramycin and nystatin resulted in the clearance of the pseudomonal infection without any evidence of toxicity from the treatment. Intra-abdominal tobramycin with parenteral colistin therapy can be used in complicated clinical settings with appropriate nephroprotection.

  13. An usual approach to treatment of a case of multidrug resistance Pseudomonas aeruginosa peritonitis: parenteral and intraperitoneal aminoglycosides and parenteral colistin

    OpenAIRE

    Ian May; Maha Abu-Khdeir; Roland Alexander Blackwood

    2012-01-01

    Infections caused by Pseudomonas aeruginosa are becoming more common and increasingly more difficult to treat due to the continued development of drug resistance. While sensitivity to colistin (polymyxin E) is well known, it is frequently avoided due to concerns of nephrotoxicity. Reported here is a case of a multi-drug resistance pseudomonal typhlitis, bacteremia and pleural cavity infection that required significant intensive care, and serial abdominal washouts. Intra-peritoneal tobramycin ...

  14. Complementary roles of neurotrophin 3 and a N-methyl-d-aspartate antagonist in the protection of noise and aminoglycoside-induced ototoxicity

    OpenAIRE

    Duan, Maoli; Agerman, Karin; Ernfors, Patrik; Canlon, Barbara

    2000-01-01

    Recent progress has been made regarding the prevention of hearing loss. However, the complete protection of both hair cells and spiral ganglion neurons, with restored function, has not yet been achieved. It has been shown that spiral ganglion neuronal loss can be prevented by neurotrophin 3 (NT3) and hair cell damage by N-methyl-d-aspartate (NMDA) receptor antagonists. Here we demonstrate that the combined treatment with MK801, a NMDA antagonist, and NT3 protect both cochlear morphology and p...

  15. Outbreak of Serratia marcescens Coproducing ArmA and CTX-M-15 Mediated High Levels of Resistance to Aminoglycoside and Extended-Spectrum Beta-Lactamases, Algeria.

    Science.gov (United States)

    Batah, Rima; Loucif, Lotfi; Olaitan, Abiola Olumuyiwa; Boutefnouchet, Nafissa; Allag, Hamoudi; Rolain, Jean-Marc

    2015-08-01

    Serratia marcescens is one of the most important pathogens responsible for nosocomial infections worldwide. Here, we have investigated the molecular support of antibiotic resistance and genetic relationships in a series of 54 S. marcescens clinical isolates collected from Eastern Algeria between December 2011 and July 2013. The 54 isolates were identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS). Antibiotic susceptibility testing was performed by disc diffusion and E-test methods. Antibiotic resistance genes were detected by polymerase chain reaction (PCR). The genetic transfer of antibiotic resistance was performed by conjugation using azide-resistant Escherichia coli J53 as the recipient strain, and plasmid analysis was done by PCR-based replicon typing. The relatedness of our isolates was determined by phylogenetic analysis based on partial sequences of four protein-encoding genes (gyrB, rpoB, infB, and atpD) and then compared to MALDI-TOF MS clustering. Thirty-five out of 54 isolates yielded an extended-spectrum β-lactamase (ESBL) phenotype and carried bla(CTX-M-15) (n=32), bla(TEM-1) (n=26), bla(TEM-71) (n=1), bla(SHV-1a) (n=1), and bla(PER-2) (n=12). Among these isolates, we identified a cluster of 15 isolates from a urology unit that coharbored ESBL and the 16S rRNA methyltransferase armA. Conjugation was successful for five selected strains, demonstrating the transferability of a conjugative plasmid of incompatibility group incL/M type. Phylogenetic analysis along with MALDI-TOF clustering likely suggested an outbreak of such isolates in the urology unit. In this study, we report for the first time the co-occurrence of armA methyltransferase with ESBL in S. marcescens clinical isolates in Eastern Algeria. PMID:25884511

  16. The aminoglycoside resistance methyltransferase Sgm impedes RsmF methylation at an adjacent rRNA nucleotide in the ribosomal A site

    DEFF Research Database (Denmark)

    Cubrilo, Sonja; Babić, Fedora; Douthwaite, Stephen;

    2009-01-01

    methylated nucleotides including m(4)Cm1402 and m(5)C1407. Modification at m(5)C1407 by the methyltransferase RsmF is impeded as Sgm gains access to its adjacent G1405 target on the 30S ribosomal subunit. An Sgm mutant (G135A), which is impaired in S-adenosylmethionine binding and confers lower resistance......Ribosome-targeting antibiotics block protein synthesis by binding at functionally important regions of the bacterial rRNA. Resistance is often conferred by addition of a methyl group at the antibiotic binding site within an rRNA region that is already highly modified with several nucleotide...... methylations. In bacterial rRNA, each methylation requires its own specific methyltransferase enzyme, and this raises the question as to how an extra methyltransferase conferring antibiotic resistance can be accommodated and how it can gain access to its nucleotide target within a short and functionally...

  17. Cholera in Vietnam: changes in genotypes and emergence of class I integrons containing aminoglycoside resistance gene cassettes in vibrio cholerae O1 strains isolated from 1979 to 1996.

    Science.gov (United States)

    Dalsgaard, A; Forslund, A; Tam, N V; Vinh, D X; Cam, P D

    1999-03-01

    The number of cholera cases and the mortality rates reported from different regions of Vietnam varied considerably in the period from 1979 to 1996, with between 2,500 and 6,000 cases reported annually from 1992 to 1995. Annual mortality rates ranged from 2.0 to 9.6% from 1979 to 1983 to less than 1.8% after 1983. Major cholera outbreaks were reported from the High Plateau region for the first time in 1994 and 1995; this is an area with limited access to health services and safe drinking-water supplies. All cases were associated with Vibrio cholerae O1. Using ribotyping, cholera toxin (CT) genotyping, and characterization of antibiotic susceptibility patterns and antibiotic resistance genes by PCR, we show that strains isolated after 1990 were clearly different from strains isolated before 1991. In contrast to strains isolated before 1991, 94% of 104 strains isolated after 1990 showed an identical ribotype R1, were resistant to sulfamethoxazole and streptomycin, and showed a different CT genotype. Furthermore, PCR analysis revealed that sulfamethoxazole-resistant strains harbored class I integrons containing a gene cassette ant(3")-1a encoding resistance to streptomycin and spectinomycin. This is, to our knowledge, the first report of class I integrons in V. cholerae. The development of cholera and the changes in the phenotypic and genotypic properties of V. cholerae O1 shown in the present study highlight the importance of monitoring V. cholerae O1 in Vietnam as in other parts of the world. In particular, the emergence of the new ribotype R1 strain containing class I integrons should be further studied. PMID:9986842

  18. Cholera in Vietnam: Changes in Genotypes and Emergence of Class I Integrons Containing Aminoglycoside Resistance Gene Cassettes in Vibrio cholerae O1 Strains Isolated from 1979 to 1996

    OpenAIRE

    Dalsgaard, A; Forslund, A; Tam, N. V.; Vinh, D. X.; Cam, P. D.

    1999-01-01

    The number of cholera cases and the mortality rates reported from different regions of Vietnam varied considerably in the period from 1979 to 1996, with between 2,500 and 6,000 cases reported annually from 1992 to 1995. Annual mortality rates ranged from 2.0 to 9.6% from 1979 to 1983 to less than 1.8% after 1983. Major cholera outbreaks were reported from the High Plateau region for the first time in 1994 and 1995; this is an area with limited access to health services and safe drinking-water...

  19. NCBI nr-aa BLAST: CBRC-LAFR-01-1393 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-LAFR-01-1393 ref|ZP_01568115.1| aminoglycoside/hydroxyurea antibiotic ... resistance kinase [Bu ... C 17616] gb|EAV67160.1| aminoglycoside/hydroxyurea antibiotic ... resistance kinase [Burkholderia multivorans ATCC 1 ...

  20. 鸡源致病性大肠埃希菌中氨基糖苷类抗生素耐药基因的检测%Detection of Aminoglycoside Resistance Genes among Pathogenic Escherichia coli from Chickens

    Institute of Scientific and Technical Information of China (English)

    王利勤; 王晶钰; 董睿; 张三东; 江跃德; 陈占莉; 李志良

    2012-01-01

    为了解鸡源致病性大肠埃希菌对氨基糖苷类抗生素的耐药性变化和钝化酶耐药基因的携带情况及耐药基因与耐药性的相关性,从陕西、河南、河北、山西、宁夏和甘肃6省(区)的部分规模化养鸡场的病、死鸡中分离鉴定320株致病性大肠埃希菌.采用K-B药敏纸片法检测分离菌对6种氨基糖苷类药物的敏感性,PCR方法检测6种氨基糖苷类钝化酶耐药基因,用DNA Star软件对获得的耐药基因序列与GenBank中的相关序列进行比对.结果显示,鸡源致病性大肠埃希菌分离株对庆大霉素、链霉素、妥布霉素、卡那霉素、新霉素和阿米卡星的耐药率分别为53.4%、49.3%、37.5%、34.7%、22.8%和5.3%,对妥布霉素和卡那霉素耐药率呈上升趋势,而对庆大霉素的耐药率虽呈下降趋势,但仍维持在40%以上.3重以上耐药菌株占80%(256/320).氨基糖苷类钝化酶基因aac(3)-Ⅱ、aph(3′)-Ⅰ和aac(6′)-Ⅰ的检出率分别为50.9%、25.9%和3.1%,未检测到aac(3)-Ⅳ、ant(3″)-Ⅰ和aph(3′)-Ⅱ基因.研究表明,分离的鸡源致病性大肠埃希菌对氨基糖苷类抗生素的耐药性普遍存在,以多重耐药为主,且对妥布霉素和卡那霉素的耐药性不断上升.耐药基因aac(3)-Ⅱ和aph(3′)-Ⅰ的检出率与其耐药性呈正相关.

  1. 儿科呼吸道致病菌氨基糖苷类抗生素耐药性%Antibiotic resistance of aminoglycosides among pathogens from respiratory tract in paediatrics

    Institute of Scientific and Technical Information of China (English)

    李明成; 李凡

    2007-01-01

    目的 探讨儿科呼吸道感染病原菌对氨基糖苷类抗生素耐药机制,监测儿科细菌耐药性变化趋势.方法 采集2005年4月~2006年5月儿科上呼吸道感染性标本,常规方法分离培养细菌,琼脂纸片(K-B)法进行抗菌药物敏感性监测,PCR检测氨基糖苷类修饰酶基因,PCR产物克隆测序.结果 242份上呼吸道感染标本共分离出革兰阴性杆菌172株(46.9%),对链霉素耐药率超过50%以上;对庆大霉素、卡那霉素、阿米卡星和奈替米星耐药率均超过35%,对衣替米星和地贝卡米星耐药率低于15%.对链霉素耐药细菌携带ANT(3")基因,对庆大霉素耐药携带AAC(3')基因.结论 吉林地区儿科呼吸道感染性疾病分离出的革兰阴性杆菌对链霉素耐药率最高,对衣替米星和地贝卡米星耐药率最低,携带单一类型的氨基糖苷类修饰酶基因.

  2. Widespread Dissemination of Aminoglycoside Resistance Genes armA and rmtB in Klebsiella pneumoniae Isolates in Taiwan Producing CTX-M-Type Extended-Spectrum β-Lactamases ▿

    OpenAIRE

    Ma, Ling; Lin, Chi-Jan; Chen, Jiun-Han; Fung, Chang-Phone; Chang, Feng-Yee; Lai, Yiu-Kay; Lin, Jung-Chung; Siu, L. K.

    2008-01-01

    Among 235 extended-spectrum β-lactamase-producing Klebsiella pneumoniae (ESBL) isolates collected from a nationwide surveillance performed in Taiwan, 102 (43.4%) were resistant to amikacin. Ninety-two of these 102 (90.2%) isolates were carrying CTX-M-type β-lactamases individually or concomitantly with SHV-type or CMY-2 β-lactamases. The armA and rmtB alleles were individually detected in 44 and 37 of these 92 isolates, respectively. One isolate contained both armA and rmtB. The coexistence o...

  3. 用药代动力学软件预测氨基糖苷类抗生素血浓度的准确性%Accuracy of prediction on aminoglycosides using Abbottbase(R) pharmacokinetics systems program

    Institute of Scientific and Technical Information of China (English)

    王丽; BINDER Lutz; OELLERICH Michael

    2004-01-01

    目的评价药代动力学软件(PKS)预测氨基糖苷类抗生素血浓度的准确性.方法严重感染病人53例,静脉点滴氨基糖苷类抗生素q 6 h共3天.血药浓度测定用偏振荧光免疫测定法.用PKS软件Baye sian模式,以首次给药后峰和低浓度为反馈值,对以后每剂量的峰和谷浓度作预测.预测准确性和精确性用平均预测误差(ME)、均方预测误差(MSE)、均方预测误差平方根(RMSE)及其95%可信限表示.将24,48,72h峰、谷浓度实测值与预测值做配对t检验.结果303次血药浓度实测值供预测.ME,MSE,RMSE及其95%可信限均在临床可接受范围内.24和48h峰浓度预测值和观察值间无显著差异(P>0.05),72 h组间差异有显著性(P<0.05).上述3个时间点的谷浓度预测值和观察值间均有显著性差异(P<0.01).结论用PKS可准确预测氨基糖苷类静脉给药后4 8h内每一剂量的峰浓度,但谷浓度预测受限.

  4. Molecular characterization of InJR06, a class 1 integron located in a conjugative plasmid of Salmonella enterica ser. Typhimurium

    OpenAIRE

    Di Conza, José; Ayala, Juan Alfonso; Porto, Ayelén; Mollerach, Marta; Gutkind, Gabriel

    2005-01-01

    The presence of class 1, 2, and 3 integrons was investigated in four pediatric isolates of Salmonella enterica ser. Typhimurium (S. Typhimurium). A class 1 integron was detected in one S. Typhimurium strain, the only one that also showed resistance to various aminoglycoside antibiotics. This integron, called InJR06, and the aminoglycoside resistance determinants were located in pS06, a large (≥ 55 kb) conjugative plasmid. A single mobile cassette (encoding the aminoglycoside adenylyltransf...

  5. Ototoxicity

    Science.gov (United States)

    ... the use of inhaled tobramycin for long-term treatment of cystic fibrosis. Can ear drops containing aminoglycosides be problematic? If ... for monitoring aminoglycoside induced ototoxicity in children with cystic ... gentamicin therapy.” Acta Otolaryngologica , 118:474–478, 1998. Zheng Y, ...

  6. In vitro activities of aztreonam, piperacillin, and ticarcillin combined with amikacin against amikacin-resistant Pseudomonas aeruginosa and P. cepacia isolates from children with cystic fibrosis.

    OpenAIRE

    Aronoff, S C; Klinger, J D

    1984-01-01

    Amikacin, combined with aztreonam, piperacillin, or ticarcillin, synergistically inhibited amikacin-resistant sputum isolates of Pseudomonas aeruginosa and P. cepacia from children with cystic fibrosis. Ticarcillin-amikacin was the least active combination. Aminoglycoside resistance should not preclude the use of beta-lactam-aminoglycoside combinations in the treatment of pulmonary infections in cystic fibrosis.

  7. Supramolecular hydrogel of kanamycin selectively sequesters 16S rRNA

    OpenAIRE

    Yang, Zhimou; Kuang, Yi; Li, Xinming; Zhou, Ning; Zhang, Ye; Xu, Bing

    2012-01-01

    As the first example of hydrogelator derived from aminoglycoside antibiotics, the hydrogel of kanamycin indicates that the hydrogel of aminoglycosides preserve the specific interaction with their macromolecular targets (e.g., 16S rRNA), thus illustrating a simple approach to explore and identify possible biological targets of supramolecular nanofibers/hydrogels.

  8. Correlation between Phenotype and Genotype of Resistance to Aminoglycoside in 98 Strains of Pathogenic E.coli from Ducks%98株鸭源致病性大肠杆菌氨基糖苷类耐药基因型与耐药表型的比较

    Institute of Scientific and Technical Information of China (English)

    于学辉; 黄兰; 杨晓农; 刘群

    2010-01-01

    旨在调查鸭致病性大肠杆菌氨基糖苷修饰酶耐药基因(AMEs基因)的携带情况,探讨耐药基因与氨基糖苷类抗生素耐药表型的相关性.对98株鸭致病性大肠杆菌采用了K-B法,选用氨基糖苷类抗生素链霉素,新霉素、庆大霉素、阿米卡星,大观霉素和卡那霉素进行药敏试验,用建立的检测氨基糖苷类AMEs主要基因的四重PCR方法对上述菌株进行分子检测,并随机选取耐药基因ant(3")-Ⅰa、aac(3)-Ⅱa和aph(3')-Ⅱa各3个阳性扩增进行克隆测序,对药敏试验结果和基因检测结果进行比较分析.结果表明,98株鸭致病性大肠杆菌有67株对上述氨基糖苷类药物中的一种或多种耐药,耐药率为68.4 %(67/98);有49株扩增出AMEs基因,AMEs基因的检出率为50%(49/98),其中ant(3')-Ⅰa的检出率为30.6%(30/98),aac(3)-Ⅱ a为13.3%(13/98),aph(3')-Ⅱa为3.1%(3/98),ant(3")-Ⅰ a+aac(3)-Ⅱa为2.0%(2/98),aac(3)-Ⅱa+aph(3')-Ⅱa为1.0%(1/98),未检出aac(6')-Ⅰb基因;序列分析结果表明,扩增产物与GenBank中的相应序列有很高的同源性(>99%)AMEs耐药基因与耐药表型的符合率为73.1 0/,(49/67),符合率从高到低依次为大观霉素60%(3/5)、庆大霉素55%(11/20)、链霉素33.3%(22/66)、卡那霉素19%(4/21)、新霉素12.5%(1/8)、阿米卡星0%(0/3).另外有4株细菌检测到相关耐药基因但耐药表型为敏感,而有22株耐药表型为耐药却未检测到相关耐药基因.鸭致病性大肠杆菌氨基糖苷类耐药基因以ant(3")-Ⅰa和aac(3)-Ⅱ a两种为主,耐药性与相关耐药基因的检出率基本星正相关.

  9. 母系遗传氨基糖苷类抗生素致聋家系的线粒体DNA突变分析%Mutation Analysis for Mitochondrial DNA in a Chinese Pedigree with Maternally Inherited Aminoglycoside Antibiotic-Induced Deafness

    Institute of Scientific and Technical Information of China (English)

    王沙燕; 高国凤; 张阮章; 石之驎; 戴勇; 任景慧

    2005-01-01

    目的确定母系遗传氨基糖苷类抗生素致聋家系的线粒体DNA突变位点,并研究其临床表型.方法应用PCR和DNA序列分析技术,对一个有明确氨基糖苷类抗生素应用史的母系遗传耳聋家系共18人(包括聋人和听力正常者)的线粒体DNA进行研究.结果该家系中有9份样品存在线粒体DNA 12SrRNA1555位点A→G的突变,其余样品为1555G点突变阴性.结论提示线粒体DNA点突变是导致该家系致聋的主要因素之一.

  10. Maternally inherited aminoglycoside-induced and nonsyndromic deafness is associated with the novel mutation in the mitochondrial DNA in a large Chinese family%母系遗传药物性聋与非综合征性聋大家系与基因突变的研究

    Institute of Scientific and Technical Information of China (English)

    赵辉; 李荣华; 王秋菊; 严庆丰; Jian-Hong Deng; 韩东一; Yidong Bai; 杨伟炎; 管敏鑫

    2005-01-01

    目的对一个氨基糖甙类药物性聋和非综合征聋的母系遗传性中国大家系进行遗传学分析,并发现全新的线粒体DNA C1494T突变.方法征集该家系中成员进行听力学检查,并收集提取DNA进行线粒体DNA PCR扩增分析,对其主要成员建立传代细胞系进行氨基糖甙类抗生素敏感试验和细胞氧消耗率检测.结果在没有接受氨基糖甙类抗生素时,一些母系遗传的成员表现为迟发/进行性听力下降,其程度不等,平均发病年龄自55岁(第2代)逐渐提前到10岁(第5代).氨基糖甙类抗生素可导致母系成员听力下降,而且接受药物的年龄似乎与听力下降程度有关.对该家系成员进行线粒体DNA测序发现高度保守的12S rRNA中1494位点C突变为T(C1494T),可以形成新的U1494-1555A碱基对,与耳聋有关的A1555G突变所造成的C1494-1555G碱基对结构相类似.当培养液中含有氨基糖甙类抗生素时,携带C1494T突变的4名听力遗传者和2名听力正常成员所建立的传代淋巴细胞系的细胞倍增时间显著延长,并且其细胞氧消耗总量显著降低.结论线粒体12S rRNA的A点是氨基糖甙类药物性聋的主要作用位点,而细胞核背景在氨基糖甙类药物性聋的发病中有重要作用,对C1494T突变的相关的耳聋发病中也有重要作用.

  11. 聋病患者线粒体DNA突变检测在指导家系成员氨基糖苷类药物个体化使用中的应用%Mitochondrial DNA mutation determination for guiding aminoglycosides antibiotics individual application in a maternal inherited deafness family

    Institute of Scientific and Technical Information of China (English)

    林文津; 郭舜民; 张亚敏; 徐榕青

    2008-01-01

    目的:确定母系遗传家系一聋病患者的线粒体DNA(mtDNA)突变位点,指导该家系其他成员氨基糖苷类药物的个体化应用.方法:应用PCR、酶切、电泳和DNA序列测序技术,对一个有明确氨基糖苷类抗生素应用史的母系遗传耳聋患者的mtDNA进行研究.结果:该患者存在mtDNA1555位点A→G的突变.结论:提示线粒体DNA点突变是导致该患者致聋的主要因素之一,该患者的正常听力的兄弟姐妹需慎用氨基糖苷类药物,该患者后代应禁用氨基糖苷类药物.

  12. Atividade da gama glutamil transpeptidase urinária, dosagens séricas de uréia e creatinina como meios diagnósticos auxiliares na nefrotoxicidade induzida por aminoglicosídeo em cães Urinary gamma glutamyl transpeptidase activity, urinalysis, bun and creatinine serum dosages as a auxiliary diagnostic mean in dogs nephrotoxicity induced by aminoglycosides

    Directory of Open Access Journals (Sweden)

    Carla Rosane de Aguiar Hennemann

    1997-06-01

    Full Text Available Foram utilizados 11 cães, hígidos, com idade entre 1 e 5 anos. Inicialmente procedeu-se à determinação dos valores basais através de cinco colheitas diárias de urina e sangue, e realizou-se a urinálise, determinação da atividade da gama glutamil transpeptidase urinária, dosagens sérica de uréia e creatinina. A nefrotoxicidade foi induzida com a utilização de10mg/kg de gentamicina, 3 vezes ao dia, durante 14 dias. As colheitas de urina foram realizadas a cada 24 hors e o sangue foi colhido a cada 48 horas, durante 14 dias. Após este período os cães foram submetidos à eutanásia, procedendo-se à necropsia, e estudo histopatológico dos rins. Os sinais clínicos apresentados foram apatia, anorexia, poliúria, oligúria, anúria, polidipsia, vômito e diarréia. Pela urinálise observou-se a ocorrência de proteinúria, glicosúria, hematúria, cilindrúria, celulúria e isostenúria; os valores de gama glutamil transpeptidase urinária elevaram-se de forma crescente a partir de 24 horas de administração da gentamicina até o final do experimento, a azotemia foi observada no 12° e 14° dias da pesquisa. Na avaliação histopatológica observou-se nefrose tubular aguda. Com base nos resultados obtidos pode-se concluir que a mensuração da atividade da gama glutamil transpeptidase urinária é um sensível indicador de lesão tubular renal possibilitando o diagnóstico precoce, juntamente com a urinálise.Eleven healthy dogs, ranging from one to five years old, were used for this study. Base line values were determined through five daily samples of urine for urinalysis and urinary gamma glutamyl transpeptidase activity, and blood for serum dosage of BUN and creatinine. Nephrotoxicity was induced using 10mg/kg of gentamicin, 3 times a day (tid, for 14 days. Urine samples were drawn every 24 hours and blood samples every 48 hours, for 14 days. After this period, the dogs were euthanized and necropsy was done for further histopathologic study. The clinical signs shown by the dogs were lethargy, anorexy, polyuria, oliguria, anuria, polydypsia, vomiting and diarrhea. Urinalysis findings were proteinuria, glucosuria, hematuria, cilindruria, celluria and decrease of urinary specific gravity and crescent values of urinary gamma glutamyl transpeptidase from 24 hours after gentamicin administration until the "end of" the experiment. Azotemia was noticed on the 12th and 14th days of the study. Acute tubular nephrosis was established in the histological evaluation. Based on the results found on this study, the measurement of the urinary gamma glutamyl transpeptidase activity might be considered a sensitive indicator of renal tubular damage allowing early diagnosis of the lesion.

  13. Unusual regioversatility of acetyltransferase Eis, a cause of drug resistance in XDR-TB

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wenjing; Biswas, Tapan; Porter, Vanessa R.; Tsodikov, Oleg V.; Garneau-Tsodikova, Sylvie (Michigan)

    2011-09-06

    The emergence of multidrug-resistant and extensively drug-resistant (XDR) tuberculosis (TB) is a serious global threat. Aminoglycoside antibiotics are used as a last resort to treat XDR-TB. Resistance to the aminoglycoside kanamycin is a hallmark of XDR-TB. Here, we reveal the function and structure of the mycobacterial protein Eis responsible for resistance to kanamycin in a significant fraction of kanamycin-resistant Mycobacterium tuberculosis clinical isolates. We demonstrate that Eis has an unprecedented ability to acetylate multiple amines of many aminoglycosides. Structural and mutagenesis studies of Eis indicate that its acetylation mechanism is enabled by a complex tripartite fold that includes two general control non-derepressible 5 (GCN5)-related N-acetyltransferase regions. An intricate negatively charged substrate-binding pocket of Eis is a potential target of new antitubercular drugs expected to overcome aminoglycoside resistance.

  14. Role of sodium in protection by extended-spectrum penicillins against tobramycin-induced nephrotoxicity.

    OpenAIRE

    Sabra, R; Branch, R A

    1990-01-01

    Salt depletion is known to potentiate aminoglycoside nephrotoxicity, while salt replacement attenuates it. Recent studies have shown that ticarcillin protects against tobramycin and gentamicin nephrotoxicity. It has been suggested that this protection is due to an interaction between ticarcillin and the aminoglycoside. However, it can also be explained by the salt load associated with ticarcillin administration. This study was conducted to examine this question. Tobramycin was administered to...

  15. Poly-l-aspartic Acid Enhances and Prolongs Gentamicin-mediated Suppression of the CFTR-G542X Mutation in a Cystic Fibrosis Mouse Model*

    OpenAIRE

    Du, Ming; Keeling, Kim M.; Fan, Liming; Liu, Xiaoli; Bedwell, David M.

    2009-01-01

    Aminoglycosides such as gentamicin have the ability to suppress translation termination at premature stop mutations, leading to a partial restoration of protein expression and function. This observation led to studies showing that this approach may provide a viable treatment for patients with genetic diseases such as cystic fibrosis that are caused by premature stop mutations. Although aminoglycoside treatment is sometimes associated with harmful side effects, several ...

  16. Comparative Pharmacodynamics of Gentamicin against Staphylococcus aureus and Pseudomonas aeruginosa†

    OpenAIRE

    Tam, Vincent H.; Kabbara, Samer; Vo, Giao; Schilling, Amy N.; Coyle, Elizabeth A.

    2006-01-01

    Aminoglycosides are often used to treat severe infections with gram-positive organisms. Previous studies have shown concentration-dependent killing by aminoglycosides of gram-negative bacteria, but limited data are available for gram-positive bacteria. We compared the in vitro pharmacodynamics of gentamicin against Staphylococcus aureus and Pseudomonas aeruginosa. Five S. aureus strains were examined (ATCC 29213 and four clinical isolates). Time-kill studies (TKS) in duplicate (baseline inocu...

  17. Selective atonal gene delivery improves balance function in a mouse model of vestibular disease

    OpenAIRE

    Schlecker, Christina; Praetorius, Mark; Brough, Douglas E.; Presler, Robert G.; Hsu, Chi; Plinkert, Peter K.; STAECKER, HINRICH

    2011-01-01

    Loss of balance is often due to loss of vestibular hair cells. In mammals, regeneration of functional hair cells in the mature sensory epithelium is limited; therefore, loss of sensory cells can lead to debilitating balance problems. Delivery of the transcription factor atonal (atoh1) after aminoglycoside ototoxicity has previously been shown to induce the transdifferentiation of supporting cells into new hair cells and restore function. A problem with mouse aminoglycoside models is that the ...

  18. Identification of clinically antibiotic resistant genes Aac(3)-IIa and Aac(6’)-Ib in wastewater samples by multiplex PCR

    OpenAIRE

    Naser Samadi; Rahim Aali; Esrafil Asgari; Hamed Mirhosaeini; Ali Shahriari; Farhad Mahmoodi; Fardin Nouri; Asad Hamdi; Farzad Fanaie; Shahla Yosefi; Saied Dadashi

    2015-01-01

    Background: Aminoglycoside antibiotics are widely used in medical centers, particularly to treat infections. The resistance developed against these agents is a huge concern in health care. A number of researchers have reported that hospital and municipal wastewaters are among the most important dissemination sources of these agent into the environment. Some, however, do not agree with this opinion. In the present study, the prevalence of aminoglycoside resistance genes was investigated in raw...

  19. Genetic and pharmacological intervention for treatment/prevention of hearing loss

    OpenAIRE

    Cotanche, Douglas A.

    2008-01-01

    Twenty years ago it was first demonstrated that birds could regenerate their cochlear hair cells following noise damage or aminoglycoside treatment. An understanding of how this structural and functional regeneration occurred might lead to the development of therapies for treatment of sensorineural hearing loss in humans. Recent experiments have demonstrated that noise exposure and aminoglycoside treatment lead to apoptosis of the hair cells. In birds, this programmed cell death induces the a...

  20. Mycothiol synthesis by an anomerization reaction through endocyclic cleavage

    Science.gov (United States)

    2016-01-01

    Summary Mycothiol is found in Gram-positive bacteria, where it helps in maintaining a reducing intracellular environment and it plays an important role in protecting the cell from toxic chemicals. The inhibition of the mycothiol biosynthesis is considered as a treatment for tuberculosis. Mycothiol contains an α-aminoglycoside, which is difficult to prepare stereoselectively by a conventional glycosylation reaction. In this study, mycothiol was synthesized by an anomerization reaction from an easily prepared β-aminoglycoside through endocyclic cleavage. PMID:26977192

  1. Bumetanide hyperpolarizes Madin-Darby canine kidney cells and enhances cellular gentamicin uptake via elevating cytosolic Ca2+ thus facilitating intermediate conductance Ca2+-activated potassium channels

    OpenAIRE

    Wang, Tian; Yang, Yu-Qin; Karasawa, Takatoshi; Wang, Qi; Phillips, Amanda; Guan, Bing-Cai; Ma, Ke-Tao; Jiang, Meiyan; Xie, Ding-Hua; Peter S. Steyger; Jiang, Zhi-Gen

    2013-01-01

    Loop diuretics such as bumetanide and furosemide enhance aminoglycoside ototoxicity when co-administered to patients and animal models. The underlying mechanism(s) is poorly understood. We investigated the effect of these diuretics on cellular uptake of aminoglycosides, using Texas Red-tagged gentamicin (GTTR), and intracellular/whole-cell recordings of Madin-Darby Canine kidney (MDCK) cells. We found that bumetanide and furosemide concentration-dependently enhanced cytoplasmic GTTR fluoresce...

  2. Acoustic trauma increases cochlear and hair cell uptake of gentamicin.

    Directory of Open Access Journals (Sweden)

    Hongzhe Li

    Full Text Available BACKGROUND: Exposure to intense sound or high doses of aminoglycoside antibiotics can increase hearing thresholds, induce cochlear dysfunction, disrupt hair cell morphology and promote hair cell death, leading to permanent hearing loss. When the two insults are combined, synergistic ototoxicity occurs, exacerbating cochlear vulnerability to sound exposure. The underlying mechanism of this synergism remains unknown. In this study, we tested the hypothesis that sound exposure enhances the intra-cochlear trafficking of aminoglycosides, such as gentamicin, leading to increased hair cell uptake of aminoglycosides and subsequent ototoxicity. METHODS: Juvenile C57Bl/6 mice were exposed to moderate or intense sound levels, while fluorescently-conjugated or native gentamicin was administered concurrently or following sound exposure. Drug uptake was then examined in cochlear tissues by confocal microscopy. RESULTS: Prolonged sound exposure that induced temporary threshold shifts increased gentamicin uptake by cochlear hair cells, and increased gentamicin permeation across the strial blood-labyrinth barrier. Enhanced intra-cochlear trafficking and hair cell uptake of gentamicin also occurred when prolonged sound, and subsequent aminoglycoside exposure were temporally separated, confirming previous observations. Acute, concurrent sound exposure did not increase cochlear uptake of aminoglycosides. CONCLUSIONS: Prolonged, moderate sound exposures enhanced intra-cochlear aminoglycoside trafficking into the stria vascularis and hair cells. Changes in strial and/or hair cell physiology and integrity due to acoustic overstimulation could increase hair cell uptake of gentamicin, and may represent one mechanism of synergistic ototoxicity.

  3. Frequency and spectrum of mitochondrial 12S rRNA variants in 440 Han Chinese hearing impaired pediatric subjects from two otology clinics

    Directory of Open Access Journals (Sweden)

    Zhou Jianjin

    2011-01-01

    Full Text Available Abstract Background Aminoglycoside ototoxicity is one of the common health problems. Mitochondrial 12S rRNA mutations are one of the important causes of aminoglycoside ototoxicity. However, the incidences of 12S rRNA mutations associated with aminoglycoside ototoxicity are less known. Methods A total of 440 Chinese pediatric hearing-impaired subjects were recruited from two otology clinics in the Ningbo and Wenzhou cities of Zhejiang Province, China. These subjects underwent clinical, genetic evaluation and molecular analysis of mitochondrial 12S rRNA. Resultant mtDNA variants were evaluated by structural and phylogenetic analysis. Results The study samples consisted of 227 males and 213 females. The age of all participants ranged from 1 years old to 18 years, with the median age of 9 years. Ninety-eight subjects (58 males and 40 females had a history of exposure to aminoglycosides, accounting for 22.3% cases of hearing loss in this cohort. Molecular analysis of 12S rRNA gene identified 41 (39 known and 2 novel variants. The incidences of the known deafness-associated 1555A > G, 1494C > T and 1095T > C mutations were 7.5%, 0.45% and 0.91% in this entire hearing-impaired subjects, respectively, and 21.4%, 2% and 2% among 98 subjects with aminoglycoside ototoxicity, respectively. The structural and phylogenetic evaluations showed that a novel 747A > G variant and known 839A > G, 1027A > G, 1310C > T and 1413T > C variants conferred increased sensitivity to aminoglycosides or nonsyndromic deafness as they were absent in 449 Chinese controls and localized at highly conserved nucleotides of this rRNA. However, other variants were polymorphisms. Of 44 subjects carrying one of definite or putative deafness-related 12S rRNA variants, only one subject carrying the 1413T > C variant harbored the 235DelC/299DelAT mutations in the GJB2 gene, while none of mutations in GJB2 gene was detected in other 43 subjects. Conclusions Mutations in mitochondrial 12S r

  4. Potent Inhibitors of Acetyltransferase Eis Overcome Kanamycin Resistance in Mycobacterium tuberculosis.

    Science.gov (United States)

    Willby, Melisa J; Green, Keith D; Gajadeera, Chathurada S; Hou, Caixia; Tsodikov, Oleg V; Posey, James E; Garneau-Tsodikova, Sylvie

    2016-06-17

    A major cause of tuberculosis (TB) resistance to the aminoglycoside kanamycin (KAN) is the Mycobacterium tuberculosis (Mtb) acetyltransferase Eis. Upregulation of this enzyme is responsible for inactivation of KAN through acetylation of its amino groups. A 123 000-compound high-throughput screen (HTS) yielded several small-molecule Eis inhibitors that share an isothiazole S,S-dioxide heterocyclic core. These were investigated for their structure-activity relationships. Crystal structures of Eis in complex with two potent inhibitors show that these molecules are bound in the conformationally adaptable aminoglycoside binding site of the enzyme, thereby obstructing binding of KAN for acetylation. Importantly, we demonstrate that several Eis inhibitors, when used in combination with KAN against resistant Mtb, efficiently overcome KAN resistance. This approach paves the way toward development of novel combination therapies against aminoglycoside-resistant TB. PMID:27010218

  5. A structure-based approach for targeting the HIV-1 genomic RNA dimerization initiation site.

    Science.gov (United States)

    Ennifar, Eric; Paillart, Jean-Christophe; Bernacchi, Serena; Walter, Philippe; Pale, Patrick; Decout, Jean-Luc; Marquet, Roland; Dumas, Philippe

    2007-10-01

    Dimerization of the genomic RNA is an important step of the HIV-1 replication cycle. The Dimerization Initiation Site (DIS) promotes dimerization of the viral genome by forming a loop-loop complex between two DIS hairpins. Crystal structures of the DIS loop-loop complex revealed an unexpected and strong similitude with the bacterial 16S ribosomal aminoacyl-tRNA site (A site), which is the target of aminoglycoside antibiotics. As a consequence of these structural and sequence similarities, the HIV-1 DIS also binds some aminoglycosides, not only in vitro, but also ex vivo, in lymphoid cells and in viral particles. Crystal structures of the DIS loop-loop in complex with several aminoglycoside antibiotics provide a detailed-view of the DIS/drug interaction and reveal some hints about possible modifications to increase the drug affinity and/or specificity. PMID:17434658

  6. First report of an OXA-48-producing multidrug-resistant Proteus mirabilis strain from Gaza, Palestine.

    Science.gov (United States)

    Chen, Liang; Al Laham, Nahed; Chavda, Kalyan D; Mediavilla, Jose R; Jacobs, Michael R; Bonomo, Robert A; Kreiswirth, Barry N

    2015-07-01

    We report the first multidrug-resistant Proteus mirabilis strain producing the carbapenemase OXA-48 (Pm-OXA-48) isolated at Al-Shifa hospital in Gaza, Palestine. Draft genome sequencing of Pm-OXA-48 identified 16 antimicrobial resistance genes, encoding resistance to β-lactams, aminoglycosides, fluoroquinolones, phenicols, streptothricin, tetracycline, and trimethoprim-sulfamethoxazole. Complete sequencing of the bla(OXA-48)-harboring plasmid revealed that it is a 72 kb long IncL/M plasmid, harboring carbapenemase gene bla(OXA-48), extended spectrum β-lactamase gene bla(CTX-M-14), and aminoglycoside resistance genes strA, strB, and aph(3')-VIb. PMID:25896692

  7. Low efficacy of tobramycin in experimental Staphylococcus aureus endocarditis

    DEFF Research Database (Denmark)

    Lerche, C. J.; Christophersen, L. J.; Trøstrup, H.;

    2015-01-01

    The empiric treatment of infective endocarditis (IE) varies widely and, in some places, a regimen of penicillin in combination with an aminoglycoside is administered. The increasing incidence of Staphylococcus aureus IE, poor tissue penetration by aminoglycosides and low frequency of penicillin...... untreated (n = 22) or tobramycin-treated (n = 13) groups. The treatment group received tobramycin once-daily. Animals were evaluated at 1 day post infection (DPI), 2 DPI or 3 DPI. Quantitative bacteriology and cytokine expression were measured for valves, myocardium and serum. A decrease of bacterial load...

  8. R-plasmic transfer from Serratia liquefaciens to Escherichia coli in vitro and in vivo in the digestive tract of gnotobiotic mice associated with human fecal flora.

    OpenAIRE

    Duval-Iflah, Y; Raibaud, P; Tancrede, C; Rousseau, M.

    1980-01-01

    It was shown that a strain of Serratia liquefaciens harbors a conjugative R-plasmid responsible for reistance to the following 14 antibiotics: ampicillin, carbenicillin, cephalothin, butirosin, neomycin, paramomycin, kanamycin, lividomycin, gentamicin, tobramycin, streptomycin, tetracycline, sulfonamide, and chloramphenicol, which belong to five families, the beta-lactamines, the aminoglycosides, the tetracyclines, the sulfonamides, and the phenicols. Resistance to th 14 antibiotics was cotra...

  9. Whole genome sequencing of diverse Shiga toxin-producing and non-producing Escherichia coli strains reveals a variety of virulence and novel antibiotic resistance plasmids

    Science.gov (United States)

    The genomes of a diverse set of Shiga toxin-producing E. coli strains and the presence of 38 plasmids among all the isolates were determined. Among the novel plasmids found, there were eight that encoded resistance genes to antibiotics, including aminoglycosides, carbapenems, penicillins, cephalosp...

  10. Investigation of the presence of extended spectrum beta-lactamases (ESBL) in multiresistant strains of E. Coli and salmonella species originated from domestic animals

    OpenAIRE

    Filipović Irina; Mišić D.; Ašanin Ružica

    2007-01-01

    Bacterial strains which possess genes to produce ESBL most often are multiresistant and also carry genes responsible for the resistance to most other antibiotics, including aminoglycosides, sulfamethoxazole+trimethoprim and fluoroquinolones. Therefore, practically the biggest contemporary clinical problem are infections of humans and animals caused by ESBL-producing strains of E. coli, Kleibsiella, Enterobacter, Proteus, Serratia, Citrobacter, Salmonella and Shigella species. The investigatio...

  11. Draft Genome Sequence of a Multidrug-Resistant Klebsiella quasipneumoniae subsp. similipneumoniae Isolate from a Clinical Source

    Science.gov (United States)

    Morris, Andrew R.; Krapp, Fiorella; Henry, Christopher S.; Tyo, Keith E.; Hauser, Alan R.

    2016-01-01

    We report here the draft genome sequence of a multidrug-resistant clinical isolate of Klebsiella quasipneumoniae subsp. similipneumoniae, KP_Z4175. This strain, isolated as part of a hospital infection-control screening program, is resistant to multiple β-lactam antibiotics, aminoglycosides, and trimethoprim-sulfamethoxazole. PMID:27231362

  12. Bacterial Enzymes and Antibiotic Resistance- Oral Presentation

    Energy Technology Data Exchange (ETDEWEB)

    Maltz, Lauren [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-25

    By using protein crystallography and X-ray diffraction, structures of bacterial enzymes were solved to gain a better understanding of how enzymatic modification acts as an antibacterial resistance mechanism. Aminoglycoside phosphotransferases (APHs) are one of three aminoglycoside modifying enzymes that confer resistance to the aminoglycoside antibiotics via enzymatic modification, rendering many drugs obsolete. Specifically, the APH(2”) family vary in their substrate specificities and also in their preference for the phosphate donor (ADP versus GDP). By solving the structures of members of the APH(2”) family of enzymes, we can see how domain movements are important to their substrate specificity. Our structure of the ternary complex of APH(2”)-IIIa with GDP and kanamycin, when compared to the known structures of APH(2”)-IVa, reveals that there are real physical differences between these two enzymes, a structural finding that explains why the two enzymes differ in their preferences for certain aminoglycosides. Another important group of bacterial resistance enzymes are the Class D β-lactamases. Oxacillinase carbapenemases (OXAs) are part of this enzyme class and have begun to confer resistance to ‘last resort’ drugs, most notably carbapenems. Our structure of OXA-143 shows that the conformational flexibility of a conserved hydrophobic residue in the active site (Val130) serves to control the entry of a transient water molecule responsible for a key step in the enzyme’s mechanism. Our results provide insight into the structural mechanisms of these two different enzymes.

  13. Characterization of class 1 integrons associated with R-plasmids in clinical Aeromonas salmonicida isolates from various geographical areas

    DEFF Research Database (Denmark)

    Schmidt, A.S.; Bruun, Morten Sichlau; Larsen, J.L.;

    2001-01-01

    Class 1 integrons were found in 26 of 40 antibiotic-resistant isolates of the fish pathogen Aeromonas salmonicida from Northern Europe and North America. Three different dhfr genes, conferring trimethoprim resistance, and one ant(3 " )1a aminoglycoside resistance gene were identified as gene...

  14. Structural Studies of Bacterial Enzymes and their Relation to Antibiotic Resistance Mechanisms - Final Paper

    Energy Technology Data Exchange (ETDEWEB)

    Maltz, Lauren [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-27

    By using protein crystallography and X-ray diffraction, structures of bacterial enzymes were solved to gain a better understanding of how enzymatic modification acts as an antibacterial resistance mechanism. Aminoglycoside phosphotransferases (APHs) are one of three aminoglycoside modifying enzymes that confer resistance to the aminoglycoside antibiotics via enzymatic modification, rendering many drugs obsolete. Specifically, the APH(2”) family vary in their substrate specificities and also in their preference for the phosphate donor (ADP versus GDP). By solving the structures of members of the APH(2”) family of enzymes, we can see how domain movements are important to their substrate specificity. Our structure of the ternary complex of APH(2”)-IIIa with GDP and kanamycin, when compared to the known structures of APH(2”)-IVa, reveals that there are real physical differences between these two enzymes, a structural finding that explains why the two enzymes differ in their preferences for certain aminoglycosides. Another important group of bacterial resistance enzymes are the Class D β- lactamases. Oxacillinase carbapenemases (OXAs) are part of this enzyme class and have begun to confer resistance to ‘last resort’ drugs, most notably carbapenems. Our structure of OXA-143 shows that the conformational flexibility of a conserved hydrophobic residue in the active site (Val130) serves to control the entry of a transient water molecule responsible for a key step in the enzyme’s mechanism. Our results provide insight into the structural mechanisms of these two different enzymes

  15. Development of a miniaturised microarray-based assay for the rapid identification of antimicrobial resistance genes in Gram-negative bacteria

    NARCIS (Netherlands)

    Batchelor, M.; Hopkins, K.L.; Liebana, E.; Slickers, P.; Ehricht, R.; Mafura, M.; Aerestrup, F.; Mevius, D.J.; Clifton-Hadley, F.A.; Woodward, M.; Davies, R.; Threlfall, J.; Anjum, F.M.

    2008-01-01

    We describe the development of a miniaturised microarray for the detection of antimicrobial resistance genes in Gram-negative bacteria. Included on the array are genes encoding resistance to aminoglycosides, trimethoprim, sulphonamides, tetracyclines and ß-lactams, including extended-spectrum ß-lact

  16. Draft Genome Sequence for a Clinical Isolate of Vancomycin-Resistant Enterococcus faecalis.

    Science.gov (United States)

    Erickson, Keesha E; Madinger, Nancy E; Chatterjee, Anushree

    2016-01-01

    We report here the draft genome sequence of a multidrug-resistant Enterococcus faecalis strain, isolated from a patient at the University of Colorado Hospital. The genome assembly is 3,040,186 bp in length with 37.6% GC content. This isolate encodes eleven resistance genes, including those for glycopeptide, aminoglycoside, macrolide-lincosamide-streptogramin, and tetracycline resistance. PMID:27340066

  17. Human Health Hazards from Antimicrobial-Resistant Escherichia coli of Animal Origin

    DEFF Research Database (Denmark)

    Hammerum, A. M.; Heuer, Ole Eske

    2009-01-01

    antimicrobial agents in food animals may add to the burden of antimicrobial resistance in humans. Bacteria from the animal reservoir that carry resistance to antimicrobial agents that are regarded as highly or critically important in human therapy (e.g., aminoglycosides, fluoroquinolones, and third- and fourth...

  18. Recent progresses in stem cell research and hearing restoration

    Institute of Scientific and Technical Information of China (English)

    YANG Hua; CHEN Xiao-wei; GAO Zhi-qiang

    2008-01-01

    @@ Serious hearing and balance impairments can occur as a result of loss of hair cells related to aging, environmental stresses (such as noises exposure) or exposure to chemotherapeutic drugs(such as cisplatin and aminoglycoside antibiotics). Because a large portion of hearing impair-ment involves loss of hair cells, regeneration or replacement of these cells is a possible alternative to prosthetic devices1.

  19. Time course of cochlear electrophysiology and morphology after combined administration of kanamycin and furosemide.

    NARCIS (Netherlands)

    Versnel, H.; Agterberg, M.J.H.; de Groot, J.C.M.J.; Smoorenburg, G.F.; Klis, S.F.L.

    2007-01-01

    In animal models of deafness, administration of an aminoglycoside in combination with a loop diuretic is often applied to produce a rapid loss of cochlear hair cells. However, the extent to which surviving hair cells remain functional after such a deafening procedure varies. In a longitudinal electr

  20. Widespread Transfer of Resistance Genes between Bacterial Species in an Intensive Care Unit: Implications for Hospital Epidemiology

    OpenAIRE

    Naiemi, N.A.; Duim, B.; Savelkoul, P. H. M.; Spanjaard, L.; de Jonge,; Bart, A.; Vandenbroucke-Grauls, C. M. J. E.; Jong, de, M.C.M.

    2005-01-01

    A transferable plasmid encoding SHV-12 extended-spectrum β-lactamase, TEM-116, and aminoglycoside resistance was responsible for two sequential clonal outbreaks of Enterobacter cloacae and Acinetobacter baumannii bacteria. A similar plasmid was present among isolates of four different bacterial species. Recognition of plasmid transfer is crucial for control of outbreaks of multidrug-resistant nosocomial pathogens.

  1. Infectious drug resistance during an outbreak of salmonellosis

    International Nuclear Information System (INIS)

    The sudden acquisition of aminoglycoside resistance among Salmonella group C1 isolates causing summer diarrhoea raised the possibility of plasmid-mediated resistance. The demonstration of circular DNA species in the resistant, but not in the sensitive salmonellae and the transfer by conjugation of antibiotic resistance to a sensitive strain of Escherichia coli, was consistent with plasmid-mediated resistance

  2. In vitro synergistic activities of tobramycin and selected beta-lactams against 75 gram-negative clinical isolates.

    OpenAIRE

    Owens, R C; Banevicius, M A; Nicolau, D. P.; Nightingale, C H; Quintiliani, R

    1997-01-01

    The microdilution checkerboard technique was utilized to distinguish synergistic activity between tobramycin and four beta-lactams: piperacillin-tazobactam, ticarcillin-clavulanate, ceftazidime, and ceftriaxone. Beta-lactam-aminoglycoside combinations were tested against 75 clinical isolates of Pseudomonas aeruginosa, Acinetobacter baumanii, Citrobacterfreundii, Serratia marcescens, and Enterobacter cloacae. Despite in vitro susceptibilities, all isolates demonstrated either synergism or indi...

  3. Enterococcus faecalis infective endocarditis

    DEFF Research Database (Denmark)

    Dahl, Anders; Rasmussen, Rasmus V; Bundgaard, Henning;

    2013-01-01

    Because of the nephrotoxic effects of aminoglycosides, the Danish guidelines on infective endocarditis were changed in January 2007, reducing gentamicin treatment in enterococcal infective endocarditis from 4 to 6 weeks to only 2 weeks. In this pilot study, we compare outcomes in patients with...... Enterococcus faecalis infective endocarditis treated in the years before and after endorsement of these new recommendations....

  4. Enhancement of antimicrobial activity of antibiotics and antifungals by the use of natural products from Pityrogramma calomelanos (L.) link

    OpenAIRE

    Souza Teógenes M.; Morais-Braga Maria F.B.; Costa José G.M.; Saraiva Antônio A.F.; Coutinho Henrique D.M.

    2012-01-01

    The ethanol extract and methanol fraction of Pityrogramma calomelanos (L.) link were evaluated for antibacterial, antifungal and modulatory activities against strains of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, C. krusei and C. tropicalis. The antimicrobial activity of the natural products was evaluated by the microdilution method associated or not with aminoglycosides and antifungals. The ethanol extract and methanol fraction of P. calomelanos ...

  5. Structure of the Antibiotic Resistance Factor Spectinomycin Phosphotransferase from Legionella pneumophila

    Energy Technology Data Exchange (ETDEWEB)

    Fong, D.; Lemke, C; Huang, J; Xiong, B; Berghuis, A

    2010-01-01

    Aminoglycoside phosphotransferases (APHs) constitute a diverse group of enzymes that are often the underlying cause of aminoglycoside resistance in the clinical setting. Several APHs have been extensively characterized, including the elucidation of the three-dimensional structure of two APH(3{prime}) isozymes and an APH(2{double_prime}) enzyme. Although many APHs are plasmid-encoded and are capable of inactivating numerous 2-deoxystreptmaine aminoglycosides with multiple regiospecificity, APH(9)-Ia, isolated from Legionella pneumophila, is an unusual enzyme among the APH family for its chromosomal origin and its specificity for a single non-2-deoxystreptamine aminoglycoside substrate, spectinomycin. We describe here the crystal structures of APH(9)-Ia in its apo form, its binary complex with the nucleotide, AMP, and its ternary complex bound with ADP and spectinomycin. The structures reveal that APH(9)-Ia adopts the bilobal protein kinase-fold, analogous to the APH(3{prime}) and APH(2{double_prime}) enzymes. However, APH(9)-Ia differs significantly from the other two types of APH enzymes in its substrate binding area and that it undergoes a conformation change upon ligand binding. Moreover, kinetic assay experiments indicate that APH(9)-Ia has stringent substrate specificity as it is unable to phosphorylate substrates of choline kinase or methylthioribose kinase despite high structural resemblance. The crystal structures of APH(9)-Ia demonstrate and expand our understanding of the diversity of the APH family, which in turn will facilitate the development of new antibiotics and inhibitors.

  6. Outer membrane alterations in multiresistant mutants of Pseudomonas aeruginosa selected by ciprofloxacin.

    OpenAIRE

    Legakis, N. J.; Tzouvelekis, L. S.; Makris, A; Kotsifaki, H

    1989-01-01

    Spontaneous mutants of Pseudomonas aeruginosa selected by ciprofloxacin were studied for outer membrane alterations. Acquisition of ciprofloxacin resistance was at least partially related to defects in lipopolysaccharide synthesis. When ciprofloxacin resistance was combined with resistance to beta-lactams and aminoglycosides, several alterations in outer membrane proteins were noted.

  7. Human leptospirosis: Management and prognosis

    OpenAIRE

    Kobayashi Y.

    2005-01-01

    As leptospirosis is a treatable disease, early diagnosis and prompt treatment are important for better prognosis. Early diagnosis depends on the knowledge of epidemiological factors, presenting features and use of appropriate laboratory tests. Early institution of appropriate antimicrobial therapy in combination with supportive therapy reduces the mortality from this disease. Leptospires are sensitive to a variety of antimicrobial agents, including penicillin, cephems, aminoglycosides, tetrac...

  8. High frequency hearing thresholds and product distortion otoacoustic emissions in cystic fibrosis patients,

    Directory of Open Access Journals (Sweden)

    Lucia Bencke Geyer

    2015-12-01

    Full Text Available ABSTRACT INTRODUCTION: The treatment of patients with cystic fibrosis involves the use of ototoxic drugs, mainly aminoglycoside antibiotics. Due to the use of these drugs, fibrocystic patients are at risk of developing hearing loss. OBJECTIVE: To evaluate the hearing of patients with cystic fibrosis by High Frequency Audiometry and Distortion Product Otoacoustic Emissions. METHODS: Cross-sectional study. The study group consisted of 39 patients (7-20 years of age with cystic fibrosis and a control group of 36 individuals in the same age group without otologic complaints, with normal audiometric thresholds and type A tympanometric curves. High Frequency Audiometry and Distortion Product Otoacoustic Emissions tests were conducted. RESULTS: The study group had significantly higher thresholds at 250, 1000, 8000, 9000, 10,000, 12,500, and 16,000 Hz (p = 0.004 as well as higher prevalence of otoacoustic emission alterations at 1000 and 6000 Hz (p = 0.001, with significantly lower amplitudes at 1000, 1400, and 6000 Hz. There was a significant association between alterations in hearing thresholds in High Frequency Audiometry with the number of courses of aminoglycosides administered (p = 0.005. Eighty-three percent of patients who completed more than ten courses of aminoglycosides had hearing loss in High Frequency Audiometry. CONCLUSION: A significant number of patients with cystic fibrosis who received repeated courses of aminoglycosides showed alterations in High Frequency Audiometry and Distortion Product Otoacoustic Emissions. The implementation of ten or more aminoglycoside cycles was associated with alterations in High Frequency Audiometry.

  9. THE STUDY OF ANTIBIOTIC- AND FAGOSENSITIVITY OF NOSOCOMIAL STRAINS BACTERIA ISOLATED FROM TRANSPLANTED PATIENTS

    Directory of Open Access Journals (Sweden)

    N. I. Gabrielan

    2011-01-01

    Full Text Available Antibiotic and fagosensitivity most etiologically important nosocomial strains of bacteria – Pseudomonas aeru- ginosa, Klebsiella pneumoniae, E. coli, Proteus spp., Staphylococcus spp. were studied. Multiple drug-resistant bacteria as gram-positive and gram-negative, isolated from 8 substrates, had been demonstrated. With regard to the sensitivity of Pseudomonas aeruginosa >40% was observed in 40–50% of the strains to aminoglycosides – aztreonam, amikacin, netilmicin, and only 23–25% of the strains – to gentamicin and levofloxacin (an average of antibiotic susceptibility was 27%. All strains of ESBL Klebsiella drew up and were sensitive only to imipenem, meropenem and aminoglycosides. Specific phages lysed 43–48% of the strains Pseudomonas aeruginosa and Klebsiella pneumoniae, E. coli, Pro- teus spp., multidrug resistant strains of Staphylococcus spp. It is proposed to introduce the use of phages in clinical practice. 

  10. Synthesis of neamine-derived pseudodisaccharides by stereo- and regio-selective functional group transformations.

    Science.gov (United States)

    Pang, Li-Juan; Wang, Dan; Zhou, Jian; Zhang, Li-He; Ye, Xin-Shan

    2009-10-21

    Neamine is normally found as a core structure of aminoglycoside antibiotics. In order to understand the relationship between the antibiotic activity and the configurations of the functional groups of neamine, a series of novel neamine analogues with functional group manipulations on the 2-deoxystreptamine (2-DOS) ring or the sugar ring were designed and synthesized. The synthetic approach involved the construction of 2-DOS derivatives by catalytic Ferrier II rearrangement, stereo- and regio-selective functional group transformations, glycosyl coupling reaction, and global deprotection. Of the synthetic neamine analogues, four compounds showed comparable 16S rRNA binding affinities with neamine, whereas they displayed lower binding affinities towards 18S rRNA than neamine, implying a lower toxicity to mammals. This strategy might have applications in the chemical synthesis of other neamine derivatives and new aminoglycoside antibiotics with improved biological activities. PMID:19795065

  11. High-level amikacin resistance in Pseudomonas aeruginosa associated with a 3'-phosphotransferase with high affinity for amikacin.

    Science.gov (United States)

    Torres, C; Perlin, M H; Baquero, F; Lerner, D L; Lerner, S A

    2000-08-01

    This work describes the characterization of the phosphotransferase enzymatic activity responsible for amikacin resistance in two clinical Pseudomona aeruginosa strains, isolated from a hospital that used amikacin as first-line aminoglycoside. Amikacin-resistant P. aeruginosa PA40 and PA43 (MIC: 128 mg/l) were shown to have APH activity with a substrate profile similar to that of APH(3')-VI. The enzyme from P. aeruginosa PA40 was purified to > 70% homogeneity. The Km of amikacin for this enzyme was 1.4 microM, the Vmax/Km ratio for amikacin was higher than for the other aminoglycosides tested and PCR and DNA sequencing ruled out the presence of aph(3')-IIps. Amikacin resistance in this strain was, therefore, associated with APH(3')-VI and the high affinity of this enzyme for amikacin could explain the high-level resistance that we observed. PMID:10929874

  12. Activation of the SOS response increases the frequency of small colony variants

    DEFF Research Database (Denmark)

    Vestergaard, Martin; Paulander, Wilhelm; Ingmer, Hanne

    2015-01-01

    BACKGROUND: In Staphylococcus aureus sub-populations of slow-growing cells forming small colony variants (SCVs) are associated with persistent and recurrent infections that are difficult to eradicate with antibiotic therapies. In SCVs that are resistant towards aminoglycosides, mutations have been...... different mechanism of action influence the formation of SCVs that are resistant to otherwise lethal concentrations of the aminoglycoside, gentamicin. We found that exposure of S. aureus to fluoroquinolones and mitomycin C increased the frequency of gentamicin resistant SCVs, while other antibiotic classes...... that environmental stimuli, including antimicrobials that reduce replication fidelity, increase the formation of SCVs through activation of the SOS response and thereby potentially promote persistent infections that are difficult to treat....

  13. Drug: D07994 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available D07994 Drug Framycetin sulfate; Neomycin B sulfate; Isofra (TN) C23H46N6O13. H2SO4 ...or topical use D06AX04 Neomycin D07994 Framycetin sulfate D09 MEDICATED DRESSINGS D09A MEDICATED DRESSINGS D09AA Medicated dressing...712.2797 712.7222 D07994.gif Antibiotic, aminoglycoside ATC code: A01AB08 A07AA01 B05CA09 D06AX04 D09AA01 J0...OR SYSTEMIC USE J01 ANTIBACTERIALS FOR SYSTEMIC USE J01G AMINOGLYCOSIDE ANTIBACTERIALS J01GB Other amin...OLOGICAL PREPARATIONS A01AB Antiinfectives and antiseptics for local oral treatment A01AB08 Neomycin D07994 Framycetin

  14. Amikacin-induced type 5 Bartter-like syndrome with severe hypocalcemia

    Directory of Open Access Journals (Sweden)

    Chrispal A

    2009-01-01

    Full Text Available Aminoglycoside-induced renal toxicity is well known and may manifest with nonoliguric renal failure or renal tubular dysfunction. Aminoglycoside-induced renal tubular dysfunction could result in diffuse damage or manifest as a Fanconi-like syndrome, Bartter-like syndrome, or distal renal tubular acidosis. We discuss a patient who developed severe renal tubular dysfunction secondary to short-term therapy with Amikacin, resulting in refractory hypokalemia, hypocalcemia, hypomagnesemia, metabolic alkalosis, and polyuria. This constellation of biochemical abnormalities mimic Type 5 Bartter′s syndrome, where there is activating mutation of the calcium sensing receptor in the thick ascending loop of Henle and the distal tubule. In this case this activation of the calcium sensing receptor was triggered by amikacin. This phenomenon has been described with gentamicin though never with amikacin. Recovery of the tubular dysfunction took 15 days following cessation of the offending drug, Amikacin.

  15. Research on the new resistance mechanism of quinolones mediated by aac(6')-Ib-cr%aac(6')-Ib-cr介导的喹喏酮类新耐药机制研究进展

    Institute of Scientific and Technical Information of China (English)

    孙攀; 殷瑜; 陈代杰

    2009-01-01

    AAC(6')- Ib are important aminoglycoside acetyltransferases.The variable gene aac(6')-Ib-cr acts on both quinolones and aminoglycosides, which belong to different classes of antibiotics based on their chemical structures, leading to the bacteria resistance. This paper briefly reviews the new resisitant mechanism of quinolones mediated by aac(6')-Ib-cr.%AAC(6')-Ib是重要的氨基糖苷乙酰基团转移酶,其变异基因aac(6')-Ib-cr可同时作用于氨基糖苷类和氟喹诺酮类两类结构不同的抗生素,是引起细菌耐药性的一种重要作用机制.该文主要对aac(6')-Ib-cr介导的喹诺酮类新耐药机制相关研究进行综述.

  16. An international multicenter study of antimicrobial consumption and resistance in Staphylococcus aureus isolates from 15 hospitals in 14 countries

    DEFF Research Database (Denmark)

    Westh, Henrik Torkil; Zinn, Christina Scheel; Rosdahl, Vibeke Thamdrup

    2004-01-01

    usage of therapeutical subgroups of antimicrobials varied significantly between hospitals. A positive correlation was found between S. aureus resistance to methicillin (MRSA) and consumption of beta-lactam combinations, between resistance to quinolones and consumption of beta-lactam combinations and...... carbapenems and resistance to aminoglycosides and consumption of beta-lactam combinations. The consumption of beta-lactamase-sensitive antibiotics was negatively correlated to resistance to methicillin, quinolones, and aminoglycosides. Usage of the different antimicrobial therapeutical subgroups was also...... correlated. Consumption of beta-lactamase-sensitive antibiotics (penicillin) was positively correlated to consumption of beta-lactamase-resistant penicillins and negatively correlated to consumption of carbapenems, quinolones, and glycopeptides, whereas consumption of cephalosporins was positively correlated...

  17. Enhancement of antimicrobial activity of antibiotics and antifungals by the use of natural products from Pityrogramma calomelanos (L. link

    Directory of Open Access Journals (Sweden)

    Souza Teógenes M.

    2012-01-01

    Full Text Available The ethanol extract and methanol fraction of Pityrogramma calomelanos (L. link were evaluated for antibacterial, antifungal and modulatory activities against strains of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, C. krusei and C. tropicalis. The antimicrobial activity of the natural products was evaluated by the microdilution method associated or not with aminoglycosides and antifungals. The ethanol extract and methanol fraction of P. calomelanos showed good activity against S. aureus when associated with aminoglycosides and with benzoilmetronidazol against species of the genus Candida. These results indicate that P. calomelanos should be studied as a possible source of natural products to combat bacteria and fungi either directly or by modulating the mechanisms of resistance of these microorganisms, enhancing the antimicrobial activity of these drugs and combating microbial resistance.

  18. [2d-generation cephalosporins in the treatment of gram-negative superinfections].

    Science.gov (United States)

    Mouton, Y; Caillaux, M; Brion, M; Fourrier, A

    1979-01-01

    The second generation cephalosporins are those drugs that are totally or partially resistant to betalactamases (cefamandole, cefuroxime) or the cephamycins (cefoxitine). This property allows them to destroy the enterobacteria resistant to cefalotine and they may have a place in the treatment of certain post-operative infections (abdominal, gynaecological, urinary) on their own or in combination with an aminoglycoside. They also may be of use in combination with an aminoglycoside in the management of secondary septicaemia infections. Outside of these indications which are dependent on the bacteriological findings, their use should be limited even when there is an absence of organisms that are Cefalotine sensitive on the antibiogram. This careful approach (which applies particularly for cefotaxine) may be abandoned once a certain quantity of resistant strains have emerged. For the time being, the second generation cephalosporins ought to be used only for specific indications, and as a general rule should not be first line antibiotic treatment. PMID:44971

  19. Tools for glycomics: mapping interactions of carbohydrates in biological systems.

    Science.gov (United States)

    Ratner, Daniel M; Adams, Eddie W; Disney, Matthew D; Seeberger, Peter H

    2004-10-01

    The emerging field of glycomics has been challenged by difficulties associated with studying complex carbohydrates and glycoconjugates. Advances in the development of synthetic tools for glycobiology are poised to overcome some of these challenges and accelerate progress towards our understanding of the roles of carbohydrates in biology. Carbohydrate microarrays, fluorescent neoglycoconjugate probes, and aminoglycoside antibiotic microarrays are among the many new tools becoming available to glycobiologists. PMID:15457538

  20. DOWN-STREAM SPATIAL DISTRIBUTION OF ANTIBIOTIC RESISTANCE TRAITS ALONG METAL CONTAMINATED STREAM REACHES

    Energy Technology Data Exchange (ETDEWEB)

    Tuckfield, C; J V Mcarthur (NOEMAIL), J

    2007-04-16

    Sediment bacteria samples were collected from three streams in South Carolina, two contaminated with multiple metals (Four Mile Creek and Castor Creek), one uncontaminated (Meyers Branch), and another metal contaminated stream (Lampert Creek) in northern Washington State. Growth plates inoculated with Four Mile Creek sample extracts show bacteria colony growth after incubation on plates containing either one of two aminoglycosides (kanamycin or streptomycin), tetracycline or chloramphenocol. This study analyzes the spatial pattern of antibiotic resistance in culturable sediment bacteria in all four streams that may be due to metal contamination. We summarize the two aminoglycoside resistance measures and the 10 metals concentrations by Principal Components Analysis. Respectively, 63% and 58% of the variability was explained in the 1st principal component of each variable set. We used the respective multivariate summary metrics (i.e. 1st principal component scores) as input measures for exploring the spatial correlation between antibiotic resistance and metal concentration for each stream reach sampled. Results show a significant and negative correlation between metals scores versus aminoglycoside resistance scores and suggest that selection for metal tolerance among sediment bacteria may influence selection for antibiotic resistance differently than previously supposed.. In addition, we borrow a method from geostatistics (variography) wherein a spatial cross-correlation analysis shows that decreasing metal concentrations scores are associated with increasing aminoglycoside resistance scores as the separation distance between sediment samples decreases, but for contaminated streams only. Since these results were counter to our initial expectation and to other experimental evidence for water column bacteria, we suspect our field results are influenced by metal bioavailability in the sediments and by a contaminant promoted interaction or ''cocktail effect

  1. In vitro activity of 79 antimicrobial agents against Corynebacterium group D2.

    OpenAIRE

    García-Rodriguez, J A; García Sánchez, J E; Muñoz Bellido, J L; Nebreda Mayoral, T; García Sánchez, E; García García, I

    1991-01-01

    Corynebacterium group D2 (CGD2) is involved in urinary tract infections in patients with underlying predisposing factors. This microorganism is highly resistant to a number of antimicrobial agents. We tested the activities of 79 antimicrobial agents against CGD2. beta-Lactams, aminoglycosides, and macrolides were ineffective. Fluorinated quinolones showed irregular activities, ofloxacin being the most active one. Doxycycline, rifampin, and mainly glycopeptides (vancomycin and teicoplanin) wer...

  2. Efficacy of Ampicillin plus Arbekacin in Experimental Rabbit Endocarditis Caused by an Enterococcus faecalis Strain with High-Level Gentamicin Resistance

    OpenAIRE

    Kak, Vivek; Donabedian, Susan M.; Zervos, Marcus J.; Kariyama, Reiko; Kumon,Hiromi; Chow, Joseph W.

    2000-01-01

    Enterococcus faecalis LC40 is an ampicillin-susceptible clinical isolate with high-level gentamicin resistance due to the aac(6′)-Ie-aph(2")-Ia aminoglycoside resistance gene. The combination of ampicillin plus arbekacin reduced mean bacterial vegetation counts significantly more than ampicillin alone or ampicillin plus gentamicin in a rabbit model of aortic-valve endocarditis caused by E. faecalis LC40.

  3. Bench-to-bedside review: preventive measures for contrast-induced nephropathy in critically ill patients

    OpenAIRE

    Berk, van den, G.E.; Tonino, S.; Fijter, de, C.; Smit, W.; Schultz, M.J

    2005-01-01

    An increasing number of diagnostic imaging procedures requires the use of intravenous radiographic contrast agents, which has led to a parallel increase in the incidence of contrast-induced nephropathy. Risk factors for development of contrast-induced nephropathy include pre-existing renal dysfunction (especially diabetic nephropathy and multiple myeloma-associated nephropathy), dehydration, congestive heart failure and use of concurrent nephrotoxic medication (including aminoglycosides and a...

  4. Generation of highly-reactive oxygen species (hROS) is closely related to hair cell damage in rat organ of Corti treated with gentamicin

    OpenAIRE

    Choung, YH; Taura, A.; Pak, K; Choi, SJ; Masuda, M.; Ryan, A.F.

    2009-01-01

    Reactive oxygen species (ROS) have been suggested to play a major role in aminoglycoside-induced hair cell (HC) loss, but are difficult to detect. Moreover, ROS can occur normally in cells where they have roles in metabolism, cell signaling and other processes. Two new probes, aminophenyl fluorescein (APF) and hydroxyphenyl fluorescein (HPF) are dyes which selectively detect highly-reactive oxygen species (hROS), those most associated with cellular damage. We assessed the presence of hROS in ...

  5. Supporting cells eliminate dying sensory hair cells to maintain epithelial integrity in the avian inner ear

    OpenAIRE

    Bird, Jonathan E.; Daudet, Nicolas; Mark E Warchol; Gale, Jonathan E.

    2010-01-01

    Epithelial homeostasis is essential for sensory transduction in the auditory and vestibular organs of the inner ear, but how it is maintained during trauma is poorly understood. To examine potential repair mechanisms, we expressed β-actin-EGFP in the chick inner ear and used live-cell imaging to study how sensory epithelia responded during aminoglycoside-induced hair cell trauma. We found that glial-like supporting cells used two independent mechanisms to rapidly eliminate dying hair cells. S...

  6. Paromomycin Affects Translation and Vesicle-Mediated Trafficking as Revealed by Proteomics of Paromomycin –Susceptible –Resistant Leishmania donovani

    OpenAIRE

    Bhavna Chawla; Anupam Jhingran; Aswini Panigrahi; Stuart, Kenneth D.; Rentala Madhubala

    2011-01-01

    Leishmania donovani is a protozoan parasite that causes visceral leishmaniasis (VL) and is responsible for significant mortality and morbidity. Increasing resistance towards antimonial drugs poses a great challenge in chemotherapy of VL. Paromomycin is an aminoglycosidic antibiotic and is one of the drugs currently being used in the chemotherapy of cutaneous and visceral leishmaniasis. To understand the mode of action of this antibiotic at the molecular level, we have investigated the global ...

  7. Overexpression of the mitochondrial methyltransferase TFB1M in the mouse does not impact mitoribosomal methylation status or hearing

    OpenAIRE

    Lee, Seungmin; Rose, Simon; Metodiev, Metodi D.; Becker, Lore; Vernaleken, Alexandra; Klopstock, Thomas; Gailus-Durner, Valerie; Fuchs, Helmut; Hrabě de Angelis, Martin; Douthwaite, Stephen; Larsson, Nils-Göran

    2015-01-01

    Mitochondrial dysfunction is a well-established cause of sensorineural deafness, but the pathophysiological events are poorly understood. Non-syndromic deafness and predisposition to aminoglycoside-induced deafness can be caused by specific mutations in the 12S rRNA gene of mtDNA and are thus maternally inherited traits. The pathophysiology induced by mtDNA mutations has traditionally been attributed to deficient oxidative phosphorylation, which causes energy crisis with functional impairment...

  8. Structural basis for S-adenosylmethionine binding and methyltransferase activity by mitochondrial transcription factor B1

    OpenAIRE

    Guja, Kip E.; Venkataraman, Krithika; Yakubovskaya, Elena; Hui SHI; Mejia, Edison; Hambardjieva, Elena; Karzai, A. Wali; Garcia-Diaz, Miguel

    2013-01-01

    Eukaryotic transcription factor B (TFB) proteins are homologous to KsgA/Dim1 ribosomal RNA (rRNA) methyltransferases. The mammalian TFB1, mitochondrial (TFB1M) factor is an essential protein necessary for mitochondrial gene expression. TFB1M mediates an rRNA modification in the small ribosomal subunit and thus plays a role analogous to KsgA/Dim1 proteins. This modification has been linked to mitochondrial dysfunctions leading to maternally inherited deafness, aminoglycoside sensitivity and di...

  9. Molecular characterization of multidrug-resistant extended-spectrum β-lactamase-producing Enterobacteriaceae isolated in Antananarivo, Madagascar.

    OpenAIRE

    Rakotonirina, Hanitra C; Garin, Benoît; Randrianirina, Frédérique; Richard, Vincent; Talarmin, Antoine; Arlet, Guillaume

    2013-01-01

    BACKGROUND: We investigated the molecular characteristics of multidrug-resistant, extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae isolated in community settings and in hospitals in Antananarivo, Madagascar. RESULTS: Forty-nine E. coli, K. pneumoniae, K. oxytoca and E. cloacae ESBL-producing isolates were studied. In antimicrobial susceptibility analyses, many of the isolates exhibited resistance to aminoglycosides, fluoroquinolones and trimethoprim-sulfamethoxazole. Gene amp...

  10. Molecular characterization of multidrug-resistant extended-spectrum β-lactamase-producing Enterobacteriaceae isolated in Antananarivo, Madagascar.

    OpenAIRE

    Rakotonirina, Hanitra C; Garin, Benoît; Randrianirina, Frédérique; Richard, Vincent; Talarmin, Antoine; Arlet, Guillaume

    2013-01-01

    Background We investigated the molecular characteristics of multidrug-resistant, extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae isolated in community settings and in hospitals in Antananarivo, Madagascar. Results Forty-nine E. coli, K. pneumoniae, K. oxytoca and E. cloacae ESBL-producing isolates were studied. In antimicrobial susceptibility analyses, many of the isolates exhibited resistance to aminoglycosides, fluoroquinolones and trimethoprim-sulfamethoxazole. Gene ampli...

  11. TETX: a novel nuclear selection marker for Chlamydomonas reinhardtii transformation

    OpenAIRE

    Garcia-Echauri, Sergio A; Cardineau, Guy A.

    2015-01-01

    Background Transformation of microalgae to obtain recombinant proteins, lipids or metabolites of economic value is of growing interest due to low costs associated with culture growth and scaling up. At present there are only three stable nuclear selection markers for the transformation of Chlamydomonas reinhardtii, which is the most commonly transformed microalgae, specifically: the aminoglycoside phosphotransferaseses aph7and aphVIII and the phleomycin resistance ble gene. As several microal...

  12. Comparison of ampicillin-sulbactam with vancomycin for treatment of experimental endocarditis due to a beta-lactamase-producing, highly gentamicin-resistant isolate of Enterococcus faecalis.

    OpenAIRE

    Lavoie, S R; Wong, E S; Coudron, P E; Williams, D S; Markowitz, S M

    1993-01-01

    Increasing antibiotic resistance in the enterococci, including the capacity for beta-lactamase production and the development of high-level aminoglycoside resistance, has complicated the treatment of serious enterococcal infections, which often require synergistic antibiotic combinations for cure. We utilized the rabbit model of aortic valve endocarditis to investigate the effects of various antibiotics, alone and in combination, against a multiply antibiotic-resistant isolate of Enterococcus...

  13. Should Moxifloxacin Be Used for the Treatment of Extensively Drug-Resistant Tuberculosis? An Answer from a Murine Model▿

    OpenAIRE

    Poissy, Julien; Aubry, Alexandra; Fernandez, Christine; Lott, Marie-Catherine; Chauffour, Aurelie; Jarlier, Vincent; Farinotti, Robert; Veziris, Nicolas

    2010-01-01

    The prevalence of extensively drug-resistant tuberculosis (XDR-TB), defined as TB that is resistant to isoniazid, rifampin, fluoroquinolones, and aminoglycosides, is rising worldwide. The extent of Mycobacterium tuberculosis resistance to fluoroquinolones depends on the mutation in the DNA gyrase, the only target of fluoroquinolones. The MIC of moxifloxacin, the most active fluoroquinolone against M. tuberculosis, may be lower than its peak serum level for some ofloxacin-resistant strains of ...

  14. Reversible tobramycin-induced bilateral high-frequency vestibular toxicity.

    Science.gov (United States)

    Walsh, R M; Bath, A P; Bance, M L

    2000-01-01

    We report an unusual case of tobramycin-induced bilateral high-frequency vestibular toxicity with subsequent clinical and objective evidence of functional recovery. In those patients with a clinical presentation suggestive of aminoglycoside-induced bilateral vestibular toxicity (ataxia and oscillopsia) and normal low-frequency (ENG-caloric) responses, high-frequency rotation chair testing should be performed to exclude a high-frequency vestibular deficit. PMID:10810261

  15. Total synthesis and development of bioactive natural products

    OpenAIRE

    TATSUTA, Kuniaki

    2008-01-01

    The first total synthesis and development of a variety of bioactive natural products have been accomplished by using carbohydrates as a chiral source. In addition, practically useful intermediates have been created, analogs of natural products have been prepared, their structure-activity relationships studied, and the large-scale preparations of medicinally useful compounds established. The key target molecules have been the “Big Four” antibiotics (macrolides, aminoglycosides, β-lactams and t...

  16. Identification of clinically antibiotic resistant genes Aac(3-IIa and Aac(6’-Ib in wastewater samples by multiplex PCR

    Directory of Open Access Journals (Sweden)

    Naser Samadi

    2015-06-01

    Full Text Available Background: Aminoglycoside antibiotics are widely used in medical centers, particularly to treat infections. The resistance developed against these agents is a huge concern in health care. A number of researchers have reported that hospital and municipal wastewaters are among the most important dissemination sources of these agent into the environment. Some, however, do not agree with this opinion. In the present study, the prevalence of aminoglycoside resistance genes was investigated in raw and effluent wastewater from hospital and municipal wastewater treatment plants. Methods: To conduct this descriptive-analytical study, 30 samples were taken according to sampling principles and cold cycle and transferred to the molecular laboratory. DNA was extracted by the freeze-thaw method using a kit (Promega. The genes aac(3-IIa and aac(6’-Ib which code aminoglycoside resistance were examined in this study. Results: The results indicated that the studied genes are present in 35% of urban and hospital wastewaters, and their frequency percentage is higher in hospital wastewater (52% than urban wastewater (48%. The studied genes were identified in 61% of raw hospital wastewater samples; however, they were not detected in the output wastewater from the studied treatment plants. Conclusion: Although, the studied genes were not detected in the final effluent, there is a high potential for their release into the environment. The current study demonstrated that the coding genes of aminoglycoside antibiotic resistance are present in raw urban and hospital wastewaters. In the case of improper exploitation of wastewater treatment plants, the output water can contaminate other environmental sections, such as soil and water resources, and result in the emission of these contaminants.

  17. Isolation, characterization, and cloning of a plasmid-borne gene encoding a phosphotransferase that confers high-level amikacin resistance in enteric bacilli.

    OpenAIRE

    Gaynes, R.; Groisman, E; Nelson, E.; Casadaban, M; Lerner, S A

    1988-01-01

    Clinical isolates of Klebsiella pneumoniae and Serratia marcescens at a hospital that had used amikacin as its principal aminoglycoside for the preceding 42 months demonstrated high-level resistance to amikacin (greater than or equal to 256 micrograms/ml), kanamycin (greater than or equal to 256 micrograms/ml), gentamicin (greater than or equal to 64 micrograms/ml), netilmicin (64 micrograms/ml), and tobramycin (greater than or equal to 16 micrograms/ml). The resistant strains contained an id...

  18. Chitosan Prevents Gentamicin-Induced Nephrotoxicity via a Carbonyl Stress-Dependent Pathway

    Directory of Open Access Journals (Sweden)

    Chu-Kung Chou

    2015-01-01

    Full Text Available Aminoglycosides are widely used to treat infections; however, their applications are limited by nephrotoxicity. With the increase of antibiotic resistance, the use of aminoglycosides is inevitable. Low-molecular-weight chitosan (LMWC has shown renal protective effects in dialysis patients. However, no study has evaluated LMWC for preventing aminoglycoside-induced nephrotoxicity or determined the mechanisms underlying the renal protective effects. In this study, LMWC (165 or 825 mg/kg/day or metformin (100 mg/kg/day was orally administered for 13 days to rats with nephropathy induced by gentamicin (GM, a kind of aminoglycoside (150 mg/kg/day i.p. for 6 days. Both LMCW doses improved renal function. Serum creatinine levels improved in rats treated with 165 and 825 mg/kg/day LMWC (from 2.14 ± 0.74 mg/dL to 1.26 ± 0.46 mg/dL and 0.69 ± 0.12 mg/dL, resp., P < 0.05. Blood urea nitrogen levels were also improved in these rats (from 73.73 ± 21.13 mg/dL to 58.70 ± 22.71 mg/dL and 28.82 ± 3.84 mg/dL, resp., P < 0.05. Additionally, renal tissue morphology improved after LMWC treatment, and accumulation of renal methylglyoxal, a damage factor associated with carbonyl stress, was reversed. These results show that LMWC prevents GM-induced renal toxicity via a carbonyl stress-dependent pathway.

  19. Isolation of Klebsiella pneumoniae strains with altered susceptibility to carbapenems not carbapenemase mediated

    OpenAIRE

    Franca Cian; Maria Luisa Deiana; Clara Fabris; Anna Belgrano; Bruno Biasioli; Marco Maria D’Andrea; Tommaso Giani; Gian Maria Rossolini

    2009-01-01

    The spread of enterobacteria producing extended-spectrum ß-lactamases (ESBLs) is sharply increasing in Italy, while the detection of isolates resistant to carbapenems is still sporadic. Isolates of Klebsiella pneumoniae resistant to all cephalosporins, aminoglycosides and fluoroquinolones have been isolated in Trieste since 2008. Because of the altered profile of resistance to carbapenems, these strains were reported as ESBL-negative and possible carbapenemases producer by the expert system, ...

  20. Postnatal Expression of Neurotrophic Factors Accessible to Spiral Ganglion Neurons in the Auditory System of Adult Hearing and Deafened Rats

    OpenAIRE

    Bailey, Erin M.; Green, Steven H.

    2014-01-01

    Spiral ganglion neurons (SGNs) receive input from cochlear hair cells and project from the cochlea to the cochlear nucleus. After destruction of hair cells with aminoglycoside antibiotics or noise, SGNs gradually die. It has been assumed that SGN death is attributable to loss of neurotrophic factors (NTFs) derived from hair cells or supporting cells in the organ of Corti (OC). We used quantitative PCR (qPCR) to assay NTF expression—neurotrophin-3 (NT-3), BDNF, GDNF, neurturin, artemin, and CN...

  1. Engineering the rRNA decoding site of eukaryotic cytosolic ribosomes in bacteria

    OpenAIRE

    Hobbie, S N; Kalapala, S K; Akshay, S.; Bruell, C M; S. Schmidt; Dabow, S; Vasella, A; Sander, P; Böttger, E C

    2007-01-01

    Structural and genetic studies on prokaryotic ribosomes have provided important insights into fundamental aspects of protein synthesis and translational control and its interaction with ribosomal drugs. Comparable mechanistic studies in eukaryotes are mainly hampered by the absence of both high-resolution crystal structures and efficient genetic models. To study the interaction of aminoglycoside antibiotics with selected eukaryotic ribosomes, we replaced the bacterial drug binding site in 16S...

  2. Clinico-Microbiological Investigation of Catheter Associated Urinary Tract Infection by Enterococcus faecalis: vanA Genotype

    OpenAIRE

    Padmavathy, Kesavaram; Praveen, Shabana; Madhavan, Radha; Krithika, Nagarajan; Kiruthiga, Alexander

    2015-01-01

    Prolonged hospitalization and exposure to third generation cephalosporins are reported to facilitate the acquisition and colonization of Vancomycin Resistant Enterococci (VRE). Though VRE is not uncommon in India, urinary tract infection with a vanA genotype is a cause of serious concern as VRE co-exhibit resistance to aminoglycosides. In India, majority of the VRE isolates recovered from hospitalized patients include Enterococcus faecium. We report a case of catheter associated urinary tract...

  3. Potentiation of Chemical Ototoxicity by Noise

    OpenAIRE

    Peter S Steyger

    2009-01-01

    High-intensity and/or prolonged exposure to noise causes temporary or permanent threshold shifts in auditory perception. Occupational exposure to solvents or administration of clinically important drugs, such as aminoglycoside antibiotics and cisplatin, also can induce permanent hearing loss. The mechanisms by which these ototoxic insults cause auditory dysfunction are still being unraveled, yet they share common sequelae, particularly generation of reactive oxygen species, that ultimately le...

  4. Cooperative Electrostatic Polymer-Antibiotic Nanoplexes

    OpenAIRE

    Vadala, Timothy Patrick

    2010-01-01

    Many pathogenic bacteria can enter phagocytic cells and replicate in them, and these intracellular bacteria are difficult to treat because the recommended antibiotics do not transport into the cells efficiently. Examples include food-borne bacteria such as Salmonella and Listeria as well as more toxic bacteria such as Brucella and the Mycobacteria that lead to tuberculosis. Current treatments utilize aminoglycoside antibiotics that are polar and positively charged and such drugs do not ente...

  5. Methodological variation in antibiotic synergy tests against enterococci.

    OpenAIRE

    Ryan, R W; Kwasnik, I; Tilton, R C

    1981-01-01

    Thirty-two human isolates of enterococci were tested for antibiotic synergy by using penicillin and one of six aminoglycosides. Three methods were used: synergy screen, microdilution checkerboard, and time-kill curves. The synergy screen accurately predicted synergy for gentamicin-penicillin combinations, and this synergy was later confirmed by time-kill curves. The microdilution checkerboard method suffered from inherent variation, and agreement with time-kill curves ranged from 92% (twofold...

  6. New Approaches Towards Recognition of Nucleic Acid Triple Helices

    OpenAIRE

    Arya, Dev P.

    2010-01-01

    We show that groove recognition of nucleic acid triple helices can be achieved with aminosugars. Among these aminosugars, neomycin is the most effective aminoglycoside (groove binder) for stabilizing a DNA triple helix. It stabilizes both the T·A·T triplex and mixed-base DNA triplexes better than known DNA minor groove binders (which usually destabilize the triplex) and polyamines. Neomycin selectively stabilizes the triplex (T·A·T and mixed base) without any effect on the DNA duplex. The sel...

  7. Increased oral bioavailability of ciprofloxacin in cystic fibrosis patients.

    OpenAIRE

    Christensson, B A; Nilsson-Ehle, I; Ljungberg, B; Lindblad, A.; Malmborg, A. S.; Hjelte, L; Strandvik, B

    1992-01-01

    The altered pharmacokinetic properties of, e.g., aminoglycosides in cystic fibrosis patients have to be considered when pulmonary exacerbations are treated. Since reported data on ciprofloxacin, a fluorinated quinolone, are conflicting, we compared intravenous and oral administration in cystic fibrosis patients when treating them for mild symptoms of pulmonary infection. All of the patients were colonized with Pseudomonas species. Ciprofloxacin was administered orally (15 mg/kg of body weight...

  8. A Comparative Analysis of the Sugar Phosphate Cyclase Superfamily Involved in Primary and Secondary Metabolism

    OpenAIRE

    Wu, Xiumei; Flatt, Patricia M.; Schlörke, Oliver; Zeeck, Axel; Dairi, Tohru; Mahmud, Taifo

    2007-01-01

    Sugar Phosphate Cyclases (SPCs) catalyze the cyclization of sugar phosphates to produce a variety of cyclitol intermediates that serve as the building blocks of many primary metabolites, e.g., aromatic amino acids, and clinically relevant secondary metabolites, e.g., aminocyclitol/aminoglycoside and ansamycin antibiotics. Feeding experiments with isotopically-labeled cyclitols revealed that cetoniacytone A, a unique C7N-aminocyclitol antibiotic isolated from an insect endophytic Actinomyces s...

  9. Efflux Pump-mediated Drug Resistance in Burkholderia

    Directory of Open Access Journals (Sweden)

    Nicole L Podnecky

    2015-04-01

    Full Text Available Several members of the genus Burkholderia are prominent pathogens. Infections caused by these bacteria are difficult to treat because of significant antibiotic resistance. Virtually all Burkholderia species are also resistant to polymyxin, prohibiting use of drugs like colistin that are available for treatment of infections caused by most other drug resistant Gram-negative bacteria. Despite clinical significance and antibiotic resistance of Burkholderia species, characterization of efflux pumps lags behind other non-enteric Gram-negative pathogens such as Acinetobacter baumannii and Pseudomonas aeruginosa. Although efflux pumps have been described in several Burkholderia species, they have been best studied in B. cenocepacia and B. pseudomallei. As in other non-enteric Gram-negatives, efflux pumps of the resistance nodulation cell division (RND family are the clinically most significant efflux systems in these two species. Several efflux pumps were described in B. cenocepacia, which when expressed confer resistance to clinically significant antibiotics, including aminoglycosides, chloramphenicol, fluoroquinolones, and tetracyclines. Three RND pumps have been characterized in B. pseudomallei, two of which confer either intrinsic or acquired resistance to aminoglycosides, macrolides, chloramphenicol, fluoroquinolones, tetracyclines, trimethoprim, and in some instances trimethoprim+sulfamethoxazole. Several strains of the host-adapted B. mallei, a clone of B. pseudomallei, lack AmrAB-OprA and are therefore aminoglycoside and macrolide susceptible. B. thailandensis is closely related to B. pseudomallei, but non-pathogenic to humans. Its pump repertoire and ensuing drug resistance profile parallels that of B. pseudomallei. An efflux pump in B. vietnamiensis plays a significant role in acquired aminoglycoside resistance. Summarily, efflux pumps are significant players in Burkholderia drug resistance.

  10. Neonatal Meningoventriculitis Due to Proteus Mirabilis – A Case Report

    OpenAIRE

    Juyal, Deepak; Rathaur, Vyas Kumar; Sharma, Neelam

    2012-01-01

    A five day old full term born baby was admitted to our Neonatal Intensive Care Unit with seizures, opisthotonous posture and was icteric upto thigh. Baby had a three day history of poor feeding, lethargy and abnormal body movements. Mother was a 29 years old primigravida and had a normal vaginal delivery at home. Sepsis profile of the patient was requested, lumbar puncture and ventricular tap was performed. Patient was put on third generation cephalosporins, aminoglycosides and phenobarbitone...

  11. Streptococcus suis, an Emerging Drug-Resistant Animal and Human Pathogen

    OpenAIRE

    Palmieri, Claudio; Varaldo, Pietro E.; Facinelli, Bruna

    2011-01-01

    Streptococcus suis, a major porcine pathogen, has been receiving growing attention not only for its role in severe and increasingly reported infections in humans, but also for its involvement in drug resistance. Recent studies and the analysis of sequenced genomes have been providing important insights into the S. suis resistome, and have resulted in the identification of resistance determinants for tetracyclines, macrolides, aminoglycosides, chloramphenicol, antifolate drugs, streptothricin,...

  12. Time course of cochlear electrophysiology and morphology after combined administration of kanamycin and furosemide.

    OpenAIRE

    Versnel, H.; Agterberg, M.J.H.; de Groot, J. C. M. J.; Smoorenburg, G.F.; Klis, S.F.L.

    2007-01-01

    In animal models of deafness, administration of an aminoglycoside in combination with a loop diuretic is often applied to produce a rapid loss of cochlear hair cells. However, the extent to which surviving hair cells remain functional after such a deafening procedure varies. In a longitudinal electrocochleographical study, we investigated the variability of cochlear function between and within guinea pigs after combined administration of kanamycin and furosemide. Concurrently, histological da...

  13. Acoustic Trauma Increases Cochlear and Hair Cell Uptake of Gentamicin

    OpenAIRE

    Hongzhe Li; Qi Wang; Steyger, Peter S.

    2011-01-01

    BACKGROUND: Exposure to intense sound or high doses of aminoglycoside antibiotics can increase hearing thresholds, induce cochlear dysfunction, disrupt hair cell morphology and promote hair cell death, leading to permanent hearing loss. When the two insults are combined, synergistic ototoxicity occurs, exacerbating cochlear vulnerability to sound exposure. The underlying mechanism of this synergism remains unknown. In this study, we tested the hypothesis that sound exposure enhances the intra...

  14. Hair cell recovery in mitotically blocked cultures of the bullfrog saccule

    OpenAIRE

    Baird, Richard A.; Burton, Miriam D.; Fashena, David S.; Naeger, Rebecca A.

    2000-01-01

    Hair cells in many nonmammalian vertebrates are regenerated by the mitotic division of supporting cell progenitors and the differentiation of the resulting progeny into new hair cells and supporting cells. Recent studies have shown that nonmitotic hair cell recovery after aminoglycoside-induced damage can also occur in the vestibular organs. Using hair cell and supporting cell immunocytochemical markers, we have used confocal and electron microscopy to examine the fate...

  15. Antibiotic usage in 2013 on a dairy CAFO in NY State, USA

    OpenAIRE

    Sarenbo, Sirkku; Doane, Marie

    2014-01-01

    Antimicrobial resistance is threatening humans and animals worldwide. Biosecurity and 1-year usage of antibiotics on a dairy concentrated animal feeding operation (CAFO) in NY State, USA, were mapped: how much antibiotics were used, for what purpose, and whether any decrease could be warranted. Approximately 493 kg antibiotics was used, of which 376 kg was ionophores (monensin and lasalocides), 79 kg penicillin, 16.5 kg lincosamides, 8.0 kg aminoglycosides, 7.7 kg sulfamides, 3.4 kg cephalosp...

  16. Multiple antibiotic resistance in Stenotrophomonas maltophilia.

    OpenAIRE

    Alonso, A.; Martínez, J L

    1997-01-01

    A cryptic multidrug resistance (MDR) system in Stenotrophomonas maltophilia, the expression of which is selectable by tetracycline, is described. Tetracycline resistance was the consequence of active efflux of the antibiotic, and it was associated with resistance to quinolones and chloramphenicol, but not to aminoglycosides or beta-lactam antibiotics. MDR is linked to the expression of an outer membrane protein (OMP54) both in a model system and in multidrug-resistant clinical isolates.

  17. [The effect of netilmicin on gram negative rods isolated in the Konya region].

    Science.gov (United States)

    Sengil, A Z; Ozenci, H; Altindiş, M; Erdoğan, E

    1988-01-01

    Netilmicin, was tested for the effect against 276 isolates of gram negative bacteria, before had used in Konya region. 15.9% of the isolates were resistant and 84.1% were sensitive to netilmicin. The effects of Netilmicin and gentamicin for 50 Pseudomonas isolates were compared. The other aminoglycosides also were tested against isolates of the bacterium, amikacin was the most active one. PMID:3252118

  18. Contribution of Efflux Pumps, Porins, and B-Lactamases to Multidrug Resistance in Clinical Isolates of Acinetobacter baumannii

    OpenAIRE

    Rumbo, C.; Gato, E.; López, M.; Ruiz de Alegría, C.; Fernández-Cuenca, F.; Martínez-Martínez, L.; Vila, J.; Pachón, J.; J. M. Cisneros; Rodríguez-Baño, Jesús; A. Pascual; Bou,G.; Tomás, M.

    2013-01-01

    Weinvestigated the mechanisms of resistance to carbapenems, aminoglycosides, glycylcyclines, tetracyclines, and quinolones in 90 multiresistant clinical strains of Acinetobacter baumannii isolated from two genetically unrelated A. baumannii clones: clone PFGEROC- 1 (53 strains producing the OXA-58B-lactamase enzyme and 18 strains with the OXA-24B-lactamase) and clone PFGE-HUI-1 (19 strains susceptible to carbapenems).Weused real-time reverse transcriptase PCR to correlate antimicrobi...

  19. In vitro evaluation of Ro 13-9904.

    OpenAIRE

    Hinkle, A M; Bodey, G P

    1980-01-01

    The in vitro activity of a new investigational cephalosporin, Ro 13-9904, was compared with those of four cephalosporins (cephalothin, cefamandole, cefoxitin, and moxalactam), five semisynthetic penicillins (mezlocillin, piperacillin, carbenicillin, ticarcillin, and azlocillin), and the aminoglycoside tobramycin. Ro 13-9904 inhibited 75% of all isolates of Enterobacteriaceae at a concentration of 6.25 micrograms/ml, including Enterobacter spp., Serratia marcescens, and indole-positive Proteus...

  20. Clinical epidemiology of the global expansion of Klebsiella pneumoniae carbapenemases

    OpenAIRE

    Munoz-Price, L. Silvia; Poirel, Laurent; Robert A Bonomo; Schwaber, Mitchell J.; Daikos, George L.; Cormican, Martin; Cornaglia, Giuseppe; Garau, Javier; Gniadkowski, Marek; Hayden, Mary K; Kumarasamy, Karthikeyan; Livermore, David M; Maya, Juan J; Nordmann, Patrice; Patel, Jean B.

    2013-01-01

    Klebsiella pneumoniae carbapenemases (KPCs) were originally identified in the USA in 1996. Since then, these versatile β-lactamases have spread internationally among Gram-negative bacteria, especially K pneumoniae, although their precise epidemiology is diverse across countries and regions. The mortality described among patients infected with organisms positive for KPC is high, perhaps as a result of the limited antibiotic options remaining (often colistin, tigecycline, or aminoglycosides). T...

  1. Imipenem resistance in nonfermenters causing nosocomial urinary tract infections.

    OpenAIRE

    Taneja N; Maharwal S; Sharma Meera

    2003-01-01

    Nonfermenting gram-negative bacilli (nonfermenters) have emerged as important nosocomial pathogens causing opportunistic infections in immunocompromised hosts. These organisms show high level of resistance to b-lactam agents, fluoroquinolones and aminoglycosides. Imipenem is a carbapenem antibiotic, which can be very useful for treatment of infections caused by nonfermenters. Eighty-five nonfermenters causing nosocomial UTI were tested for MIC to imipenem by agar dilution method. Resistance t...

  2. Live imaging the phagocytic activity of inner ear supporting cells in response to hair cell death.

    Science.gov (United States)

    Monzack, E L; May, L A; Roy, S; Gale, J E; Cunningham, L L

    2015-12-01

    Hearing loss and balance disorders affect millions of people worldwide. Sensory transduction in the inner ear requires both mechanosensory hair cells (HCs) and surrounding glia-like supporting cells (SCs). HCs are susceptible to death from aging, noise overexposure, and treatment with therapeutic drugs that have ototoxic side effects; these ototoxic drugs include the aminoglycoside antibiotics and the antineoplastic drug cisplatin. Although both classes of drugs are known to kill HCs, their effects on SCs are less well understood. Recent data indicate that SCs sense and respond to HC stress, and that their responses can influence HC death, survival, and phagocytosis. These responses to HC stress and death are critical to the health of the inner ear. Here we have used live confocal imaging of the adult mouse utricle, to examine the SC responses to HC death caused by aminoglycosides or cisplatin. Our data indicate that when HCs are killed by aminoglycosides, SCs efficiently remove HC corpses from the sensory epithelium in a process that includes constricting the apical portion of the HC after loss of membrane integrity. SCs then form a phagosome, which can completely engulf the remaining HC body, a phenomenon not previously reported in mammals. In contrast, cisplatin treatment results in accumulation of dead HCs in the sensory epithelium, accompanied by an increase in SC death. The surviving SCs constrict fewer HCs and display impaired phagocytosis. These data are supported by in vivo experiments, in which cochlear SCs show reduced capacity for scar formation in cisplatin-treated mice compared with those treated with aminoglycosides. Together, these data point to a broader defect in the ability of the cisplatin-treated SCs, to preserve tissue health in the mature mammalian inner ear. PMID:25929858

  3. Current Epidemiology and Growing Resistance of Gram-Negative Pathogens

    OpenAIRE

    Livermore, David M.

    2012-01-01

    In the 1980s, Gram-negative pathogens appeared to have been beaten by oxyimino-cephalosporins, carbapenems, and fluoroquinolones. Yet these pathogens have fought back, aided by their membrane organization, which promotes the exclusion and efflux of antibiotics, and by a remarkable propensity to recruit, transfer, and modify the expression of resistance genes, including those for extended-spectrum β-lactamases (ESBLs), carbapenemases, aminoglycoside-blocking 16S rRNA methylases, and even a qui...

  4. Draft Whole-Genome Sequence of VIM-1-Producing Multidrug-Resistant Enterobacter cloacae EC_38VIM1

    Science.gov (United States)

    Villa, Jennifer; Viedma, Esther; Otero, Joaquín R.

    2013-01-01

    The VIM-1-producing multidrug-resistant strain Enterobacter cloacae was isolated from blood culture. The strain showed multiple resistances to clinically used antibiotics, including all β-lactams, fluoroquinolones, aminoglycosides, and sulfonamides. Sequence analysis showed the presence of 14 genes associated with resistance to antibiotics, including the metallo-β-lactamase VIM-1 gene, which was located in a class 1 integron. PMID:24009122

  5. Draft Genome Sequence of Uropathogenic Escherichia coli Strain NB8.

    Science.gov (United States)

    Weng, Xing-Bei; Mi, Zu-Huang; Wang, Chun-Xin; Zhu, Jian-Ming

    2016-01-01

    Escherichia coli NB8 is a clinical pyelonephritis isolate. Here, we report the draft genome sequence of uropathogenic E. coli NB8, which contains drug resistance genes encoding resistance to beta-lactams, aminoglycosides, quinolones, macrolides, colistin, sulfonamide-trimethoprim, and tetracycline. NB8 infects the kidney and bladder, making it an important tool for studying E. coli pathogenesis. PMID:27609920

  6. Mutation of Salmonella paratyphi A conferring cross-resistance to several groups of antibiotics by decreased permeability and loss of invasiveness.

    OpenAIRE

    Gutmann, L; Billot-Klein, D; Williamson, R.; Goldstein, F W; Mounier, J; Acar, J F; Collatz, E

    1988-01-01

    A spontaneous one-step mutant of Salmonella paratyphi A selected on ampicillin showed cross-resistance to all beta-lactam antibiotics except imipenem and to aminoglycosides, chloramphenicol, tetracycline, trimethoprim, and quinolones. It also grew as small colonies. Examination of the cell envelope of the mutant showed a quantitative decrease in three major outer membrane proteins of 40.6, 39.6 (presumably porins), and 24 kilodaltons and quantitative as well as qualitative modifications in th...

  7. Development of core-shell nanostructure encapsulating gentamicin as efficient drug delivery system against intracellular Salmonella

    OpenAIRE

    Ranjan, Ashish

    2009-01-01

    Intracellular pathogens like Salmonella have developed various mechanisms to evade host defenses, and they can establish infections. Treatment and eradication are difficult due to our inability in achieving the optimum concentrations of cell-impermeable aminoglycosides like gentamicin within these cells. In this dissertation, we hypothesize that developing a novel core-shell methodology for incorporating high amounts of gentamicin into the cores with either hydrophilic or amphiphilic shell wi...

  8. Antimicrobial susceptibilities of Stomatococcus mucilaginosus and of Micrococcus spp.

    OpenAIRE

    von Eiff, C; Herrmann, M; Peters, G.

    1995-01-01

    The in vitro susceptibilities of 63 isolates of Stomatococcus mucilaginosus and of 188 isolates of Micrococcus spp. to 18 antimicrobial agents were determined by the agar dilution method. Many beta-lactams, imipenem, rifampin, and the glycopeptides were shown to be active in vitro against Stomatococcus and Micrococcus isolates, whereas the activities of antibiotics such as some aminoglycosides, erythromycin, and fosfomycin against an important number of these microorganisms are limited.

  9. Sildenafil Ameliorates Gentamicin-Induced Nephrotoxicity in Rats: Role of iNOS and eNOS

    OpenAIRE

    Morsy, Mohamed A.; Ibrahim, Salwa A.; Amin, Entesar F.; Maha Y Kamel; Rehab A. Rifaai; Hassan, Magdy K.

    2014-01-01

    Gentamicin, an aminoglycoside antibiotic, is used for the treatment of serious Gram-negative infections. However, its usefulness is limited by its nephrotoxicity. Sildenafil, a selective phosphodiesterase-5 inhibitor, was reported to prevent or decrease tissue injury. The aim of this study is to evaluate the potential protective effects of sildenafil on gentamicin-induced nephrotoxicity in rats. Male Wistar rats were injected with gentamicin (100 mg/kg/day, i.p.) for 6 days with and without s...

  10. Dimethyl Sulfoxide (DMSO) Exacerbates Cisplatin-induced Sensory Hair Cell Death in Zebrafish (Danio rerio)

    OpenAIRE

    Uribe, Phillip M.; Mueller, Melissa A.; Gleichman, Julia S.; Kramer, Matthew D.; Qi Wang; Martha Sibrian-Vazquez; Strongin, Robert M.; Peter S Steyger; Douglas A Cotanche; Matsui, Jonathan I.

    2013-01-01

    Inner ear sensory hair cells die following exposure to aminoglycoside antibiotics or chemotherapeutics like cisplatin, leading to permanent auditory and/or balance deficits in humans. Zebrafish (Danio rerio) are used to study drug-induced sensory hair cell death since their hair cells are similar in structure and function to those found in humans. We developed a cisplatin dose-response curve using a transgenic line of zebrafish that expresses membrane-targeted green fluorescent protein under ...

  11. Extremely low penetrance of deafness associated with the mitochondrial 12S rRNA mutation in 16 Chinese families: Implication for early detection and prevention of deafness

    International Nuclear Information System (INIS)

    Mutations in mitochondrial DNA (mtDNA) have been found to be associated with sensorineural hearing loss. We report here the clinical, genetic, and molecular characterization of 16 Chinese pedigrees (a total of 246 matrilineal relatives) with aminoglycoside-induced impairment. Clinical evaluation revealed the variable phenotype of hearing impairment including audiometric configuration in these subjects, although these subjects share some common features: being bilateral and sensorineural hearing impairment. Strikingly, these Chinese pedigrees exhibited extremely low penetrance of hearing loss, ranging from 4% to 18%, with an average of 8%. In particular, nineteen of 246 matrilineal relatives in these pedigrees had aminoglycoside-induced hearing loss. Mutational analysis of the mtDNA in these pedigrees showed the presence of homoplasmic 12S rRNA A1555G mutation, which has been associated with hearing impairment in many families worldwide. The extremely low penetrance of hearing loss in these Chinese families carrying the A1555G mutation strongly supports the notion that the A1555G mutation itself is not sufficient to produce the clinical phenotype. Children carrying the A1555G mutation are susceptible to the exposure of aminoglycosides, thereby inducing or worsening hearing impairment, as in the case of these Chinese families. Using those genetic and molecular approaches, we are able to diagnose whether children carry the ototoxic mtDNA mutation. Therefore, these data have been providing valuable information and technology to predict which individuals are at risk for ototoxicity, to improve the safety of aminoglycoside therapy, and eventually to decrease the incidence of deafness

  12. Identification of genetic and chemical modulators of zebrafish mechanosensory hair cell death.

    Directory of Open Access Journals (Sweden)

    Kelly N Owens

    2008-02-01

    Full Text Available Inner ear sensory hair cell death is observed in the majority of hearing and balance disorders, affecting the health of more than 600 million people worldwide. While normal aging is the single greatest contributor, exposure to environmental toxins and therapeutic drugs such as aminoglycoside antibiotics and antineoplastic agents are significant contributors. Genetic variation contributes markedly to differences in normal disease progression during aging and in susceptibility to ototoxic agents. Using the lateral line system of larval zebrafish, we developed an in vivo drug toxicity interaction screen to uncover genetic modulators of antibiotic-induced hair cell death and to identify compounds that confer protection. We have identified 5 mutations that modulate aminoglycoside susceptibility. Further characterization and identification of one protective mutant, sentinel (snl, revealed a novel conserved vertebrate gene. A similar screen identified a new class of drug-like small molecules, benzothiophene carboxamides, that prevent aminoglycoside-induced hair cell death in zebrafish and in mammals. Testing for interaction with the sentinel mutation suggests that the gene and compounds may operate in different pathways. The combination of chemical screening with traditional genetic approaches is a new strategy for identifying drugs and drug targets to attenuate hearing and balance disorders.

  13. INTERACTIVE EFFECTS OF DIFFERENT DURATION OF LITHIUM PRETREATMENT WITH AMIKACIN AND GENTAMICIN ONAPOMORPHINE-INDUCED LICKING IN RATS

    Directory of Open Access Journals (Sweden)

    MOHAMMAD SHARIFZADEH

    2000-07-01

    Full Text Available In this study the hypothesis that aminoglycoside antibiotics and lithium may influence apomorphine-induced licking via their effects on phosphoinositide pathways and calcium stores were investigated in male rats. Subcutaneous administration of apomorphine (0.1,0.25 and 0.5 mg/kg to rats induced licking in a dose-dependent manner and the maximum response was obtained by the dose of 0.5 mg/kg of the drug. Intracerebroventricular injections of amikacin (5, 25 and 50 ug/rat and gentamicin (10, 20 and 40 ug/rat decreased the apomorphine-induced licking significantly. Pretreatment of animals with lithium (600 mg/1 for 7,14 and 21 days increased licking induced by apomorphine. The inhibitory effects of amikacin and high dose of gentamicin were not affected by lithium pretreatment for 14 and 28 days. These findings indicate the possible involvement of phosphoinositide cascade in alterations of apomorphine-induced licking by aminoglycoside antibiotics and lithium in the brain. Also it is suggested that type and dose of aminoglycoside antibiotics and duration of lithium administration probably have different effects on responses mediated by phosphoinositide hydrolysis.

  14. NaHS Protects Cochlear Hair Cells from Gentamicin-Induced Ototoxicity by Inhibiting the Mitochondrial Apoptosis Pathway.

    Directory of Open Access Journals (Sweden)

    Yaodong Dong

    Full Text Available Aminoglycoside antibiotics such as gentamicin could cause ototoxicity in mammalians, by inducing oxidative stress and apoptosis in sensory hair cells of the cochlea. Sodium hydrosulfide (NaHS is reported to alleviate oxidative stress and apoptosis, but its role in protecting aminoglycoside-induced hearing loss is unclear. In this study, we investigated the anti-oxidant and anti-apoptosis effect of NaHS in in vitro cultured House Ear Institute-Organ of Corti 1 (HEI-OC1 cells and isolated mouse cochlea. Results from cultured HEI-OC1 cells and cochlea consistently indicated that NaHS exhibited protective effects from gentamicin-induced ototoxicity, evident by maintained cell viability, hair cell number and cochlear morphology, reduced reactive oxygen species production and mitochondrial depolarization, as well as apoptosis activation of the intrinsic pathway. Moreover, in the isolated cochlear culture, NaHS was also demonstrated to protect the explant from gentamicin-induced mechanotransduction loss. Our study using multiple in vitro models revealed for the first time, the potential of NaHS as a therapeutic agent in protecting against aminoglycoside-induced hearing loss.

  15. Study of modifiers factors associated to mitochondrial mutations in individuals with hearing impairment

    International Nuclear Information System (INIS)

    Hearing impairment is the most prevalent sensorial deficit in the general population. Congenital deafness occurs in about 1 in 1000 live births, of which approximately 50% has hereditary cause in development countries. Non-syndromic deafness can be caused by mutations in both nuclear and mitochondrial genes. Mutations in mtDNA have been associated with aminoglycoside-induced and non-syndromic deafness in many families worldwide. However, the nuclear background influences the phenotypic expression of these pathogenic mutations. Indeed, it has been proposed that nuclear modifier genes modulate the phenotypic manifestation of the mitochondrial A1555G mutation in the MTRNR1 gene. The both putative nuclear modifiers genes TRMU and MTO1 encoding a highly conserved mitochondrial related to tRNA modification. It has been hypothesizes that human TRMU and also MTO1 nuclear genes may modulate the phenotypic manifestation of deafness-associated mitochondrial mutations. The aim of this work was to elucidate the contribution of mitochondrial mutations, nuclear modifier genes mutations and aminoglycoside exposure in the deafness phenotype. Our findings suggest that the genetic background of individuals may play an important role in the pathogenesis of deafness-associated with mitochondrial mutation and aminoglycoside-induced.

  16. Extremely low penetrance of hearing loss in four Chinese families with the mitochondrial 12S rRNA A1555G mutation

    International Nuclear Information System (INIS)

    Mutations in mitochondrial DNA (mtDNA) have been found to be associated with sensorineural hearing loss. We report here the clinical, genetic, and molecular characterization of four Chinese pedigrees with aminoglycoside-induced and nonsyndromic hearing impairment. Clinical evaluation revealed the variable phenotype of hearing impairment including audiometric configuration in these subjects, although these subjects share some common features: bilateral and sensorineural hearing impairment. Strikingly, these Chinese pedigrees exhibited extremely low penetrance of hearing loss (5.2%, 4.8%, 4.2%, and 13.3%, respectively, and with an average 8% penetrance). In particular, four of all five affected matrilineal relatives of these pedigrees had aminoglycoside-induced hearing loss. Sequence analysis of the complete mitochondrial genomes in these pedigrees showed the distinct sets of mtDNA polymorphism, in addition to the identical homoplasmic A1555G mutation, associated with hearing impairment in many families from different genetic backgrounds. The fact that mtDNA of those pedigrees belonged to different haplogroups R9a, N9a, D4a, and D4 suggested that the A1555G mutation occurred sporadically and multiplied through evolution of the mtDNA in China. However, there was the absence of functionally significant mutations in tRNA and rRNAs or secondary LHON mutations in these Chinese families. These data imply that the nuclear background or/and mitochondrial haplotype may not play a significant role in the phenotypic expression of the A1555G mutation in these Chinese pedigrees. However, aminoglycoside appears to be a major modifier factor for the phenotypic manifestation of the A1555G mutation in these Chinese families

  17. Neomycin damage and regeneration of hair cells in both mechanoreceptor and electroreceptor lateral line organs of the larval Siberian sturgeon (Acipenser baerii).

    Science.gov (United States)

    Fan, Chunxin; Zou, Sha; Wang, Jian; Zhang, Bo; Song, Jiakun

    2016-05-01

    The lateral line found in some amphibians and fishes has two distinctive classes of sensory organs: mechanoreceptors (neuromasts) and electroreceptors (ampullary organs). Hair cells in neuromasts can be damaged by aminoglycoside antibiotics and they will regenerate rapidly afterward. Aminoglycoside sensitivity and the capacity for regeneration have not been investigated in ampullary organs. We treated Siberian sturgeon (Acipenser baerii) larvae with neomycin and observed loss and regeneration of sensory hair cells in both organs by labeling with DASPEI and scanning electron microscopy (SEM). The numbers of sensory hair cells in both organs were reduced to the lowest levels at 6 hours posttreatment (hpt). New sensory hair cells began to appear at 12 hpt and were regenerated completely in 7 days. To reveal the possible mechanism for ampullary hair cell regeneration, we analyzed cell proliferation and the expression of neural placodal gene eya1 during regeneration. Both cell proliferation and eya1 expression were concentrated in peripheral mantle cells and both increased to the highest level at 12 hpt, which is consistent with the time course for regeneration of the ampullary hair cells. Furthermore, we used Texas Red-conjugated gentamicin in an uptake assay following pretreatment with a cation channel blocker (amiloride) and found that entry of the antibiotic was suppressed in both organs. Together, our results indicate that ampullary hair cells in Siberian sturgeon larvae can be damaged by neomycin exposure and they can regenerate rapidly. We suggest that the mechanisms for aminoglycoside uptake and hair cell regeneration are conserved for mechanoreceptors and electroreceptors. J. Comp. Neurol. 524:1443-1456, 2016. © 2015 Wiley Periodicals, Inc. PMID:26502298

  18. In vivo characteristics of targeted drug-carrying filamentous bacteriophage nanomedicines

    Directory of Open Access Journals (Sweden)

    Vaks Lilach

    2011-12-01

    Full Text Available Abstract Background Targeted drug-carrying phage nanomedicines are a new class of nanomedicines that combines biological and chemical components into a modular nanometric drug delivery system. The core of the system is a filamentous phage particle that is produced in the bacterial host Escherichia coli. Target specificity is provided by a targeting moiety, usually an antibody that is displayed on the tip of the phage particle. A large drug payload is chemically conjugated to the protein coat of the phage via a chemically or genetically engineered linker that provides for controlled release of the drug after the particle homed to the target cell. Recently we have shown that targeted drug-carrying phage nanomedicines can be used to eradicate pathogenic bacteria and cultured tumor cells with great potentiation over the activity of the free untargeted drug. We have also shown that poorly water soluble drugs can be efficiently conjugated to the phage coat by applying hydrophilic aminoglycosides as branched solubility-enhancing linkers. Results With an intention to move to animal experimentation of efficacy, we tested anti-bacterial drug-carrying phage nanomedicines for toxicity and immunogenicity and blood pharmacokinetics upon injection into mice. Here we show that anti-bacterial drug-carrying phage nanomedicines that carry the antibiotic chloramphenicol conjugated via an aminoglycoside linker are non-toxic to mice and are greatly reduced in immunogenicity in comparison to native phage particles or particles to which the drug is conjugated directly and are cleared from the blood more slowly in comparison to native phage particles. Conclusion Our results suggest that aminoglycosides may serve as branched solubility enhancing linkers for drug conjugation that also provide for a better safety profile of the targeted nanomedicine.

  19. Marker-free plasmids for gene therapeutic applications--lack of antibiotic resistance gene substantially improves the manufacturing process.

    Science.gov (United States)

    Mairhofer, Jürgen; Cserjan-Puschmann, Monika; Striedner, Gerald; Nöbauer, Katharina; Razzazi-Fazeli, Ebrahim; Grabherr, Reingard

    2010-04-01

    Plasmid DNA is being considered as a promising alternative to traditional protein vaccines or viral delivery methods for gene therapeutic applications. DNA-based products are highly flexible, stable, are easily stored and can be manufactured on a large scale. Although, much safer than viral approaches, issues have been raised with regard to safety due to possible integration of plasmid DNA into cellular DNA or spread of antibiotic resistance genes to intestinal bacteria by horizontal gene transfer. Accordingly, there is interest in methods for the production of plasmid DNA that lacks the antibiotic resistance gene to further improve their safety profile. Here, we report for the first time the gram-scale manufacturing of a minimized plasmid that is devoid of any additional sequence elements on the plasmid backbone, and merely consists of the target expression cassette and the bacterial origin of replication. Three different host/vector combinations were cultivated in a fed-batch fermentation process, comparing the progenitor strain JM108 to modified strains JM108murselect, hosting a plasmid either containing the aminoglycoside phosphotransferase which provides kanamycin resistance, or a marker-free variant of the same plasmid. The metabolic load exerted by expression of the aminoglycoside phosphotransferase was monitored by measuring ppGpp- and cAMP-levels. Moreover, we revealed that JM108 is deficient of the Lon protease and thereby refined the genotype of JM108. The main consequences of Lon-deficiency with regard to plasmid DNA production are discussed herein. Additionally, we found that the expression of the aminoglycoside phosphotransferase, conferring resistance to kanamycin, was very high in plasmid DNA producing processes that actually inclusion bodies were formed. Thereby, a severe metabolic load on the host cell was imposed, detrimental for overall plasmid yield. Hence, deleting the antibiotic resistance gene from the vector backbone is not only beneficial

  20. Expression of the RND-Type Efflux Pump AdeABC in Acinetobacter baumannii Is Regulated by the AdeRS Two-Component System

    OpenAIRE

    Marchand, Isabelle; Damier-Piolle, Laurence; Courvalin, Patrice; Lambert, Thierry

    2004-01-01

    The AdeABC pump of Acinetobacter baumannii BM4454, which confers resistance to various antibiotic classes including aminoglycosides, is composed of the AdeA, AdeB, and AdeC proteins; AdeB is a member of the RND superfamily. The adeA, adeB, and adeC genes are contiguous and adjacent to adeS and adeR, which are transcribed in the opposite direction and which specify proteins homologous to sensors and regulators of two-component systems, respectively (S. Magnet, P. Courvalin, and T. Lambert, Ant...

  1. 3 Certain Shell Hospital Inpatient Antibiotic Uses are Analysed%某三甲医院住院病人抗生素利用分析

    Institute of Scientific and Technical Information of China (English)

    刘伟卿

    2002-01-01

    Objective We appraise the application condition of 3 certain shell hospital antibiotics. Methods According to medicine, we use research method. As the 280 certain courtyard regular inpatients of May 2001 use the condition of antibiotic,investigate. With the survey that DDD studies as medicine use, we worth. Is judgement doctor with DUI reasonable use the standard of medicine? Results 185 examples are used antibiotic, take 66.07%. With penicillins, Quinolones and Aminoglycosides use count frequently highest. Before locating in, 5 antibiotics are in proper order. Penicillin G, Clindamycin,Amikacin, Sodium Cefotaxime, and Ciprofloxacin. Conclusions The most antibiotic DUI ≤ 1, whole, the application ofantibiotic is reasonable.

  2. Different uptake of gentamicin through TRPV1 and TRPV4 channels determines cochlear hair cell vulnerability

    OpenAIRE

    Lee, Jeong-Han; Park, Channy; Kim, Se-Jin; Kim, Hyung-Jin; Oh, Gi-Su; Shen, Aihua; So, Hong-Seob; Park, Raekil

    2013-01-01

    Hair cells at the base of the cochlea appear to be more susceptible to damage by the aminoglycoside gentamicin than those at the apex. However, the mechanism of base-to-apex gradient ototoxicity by gentamicin remains to be elucidated. We report here that gentamicin caused rodent cochlear hair cell damages in a time- and dose-dependent manner. Hair cells at the basal turn were more vulnerable to gentamicin than those at the apical turn. Gentamicin-conjugated Texas Red (GTTR) uptake was predomi...

  3. Minocycline Protection of Neomycin Induced Hearing Loss in Gerbils

    OpenAIRE

    Alan M Robinson; Irena Vujanovic; Claus-Peter Richter

    2015-01-01

    This animal study was designed to determine if minocycline ameliorates cochlear damage is caused by intratympanic injection of the ototoxic aminoglycoside antibiotic neomycin. Baseline auditory-evoked brainstem responses were measured in gerbils that received 40 mM intratympanic neomycin either with 0, 1.2, or 1.5 mg/kg intraperitoneal minocycline. Four weeks later auditory-evoked brainstem responses were measured and compared to the baseline measurements. Minocycline treatments of 1.2 mg/kg...

  4. Antimicrobial sensitivity and frequency of DRUG resistance among bacterial strains isolated from cancer patients

    International Nuclear Information System (INIS)

    Blood stream infections (bacteremia) is potentially life threatening. Concomitant with a change in the incidence and epidemiology of infecting organisms, there has been an increase in resistance to many antibiotic compounds. The widespread emergence of resistance among bacterial pathogens has an impact on our ability to treat patients effectively. The changing spectrum of microbial pathogens and widespread emergence of microbial resistance to antibiotic drugs has emphasized the need to monitor the prevalence of resistance in these strains. In the present study frequency of isolation of clinically significant bacteria and their susceptibility and resistance pattern against a wide range of antimicrobial drugs from positive blood cultures collected during 2001-2003 was studied. A total of 102 consecutive isolates were found with 63% gram positive and 44% gram negative strains. The dominating pathogens were Staphylococcus aureus (51%), Streptococci (31%), Pseudomonas (40%), Proteus (13%), Klebsiella (13%). The isolated strains were tested against a wide range of antibiotics belonging to cephalosporins, aminoglycosides and quinolone derivative group by disk diffusion method. It has been observed that isolated strains among gram positive and negative strains showed different level of resistance against aminoglycosides and cephalosporin group of antibiotics with gram positives showing highest number and frequency of resistance against aminoglycosides (40-50%) and cephalosporins.(35-45%) whereas cephalosporins were found to be more effective against gram negatives with low frequency of resistant strains. Cabapenem and quinolone derivative drugs were found to be most effective among other groups in both gram positive and negative strains with 23-41% strains found sensitive to these two drugs. The frequency of sensitive strains against aminoglycoside and cephalosporin in gram negative and gram positive strains were found to be decreasing yearwise with a trend towards an

  5. Development of a miniaturised microarray-based assay for the rapid identification of antimicrobial resistance genes in Gram-negative bacteria

    DEFF Research Database (Denmark)

    Batchelor, Miranda; Hopkins, Katie L; Liebana, Ernesto;

    2008-01-01

    We describe the development of a miniaturised microarray for the detection of antimicrobial resistance genes in Gram-negative bacteria. Included on the array are genes encoding resistance to aminoglycosides, trimethoprim, sulphonamides, tetracyclines and beta-lactams, including extended...... also seen in the number and type of resistance genes harboured by E. coli and Salmonella strains. The array provides an effective, fast and simple method for detection of resistance genes in clinical isolates suitable for use in diagnostic laboratories, which in future will help to understand the...... epidemiology of isolates and to detect gene linkage in bacterial populations. (C) 2008 Published by Elsevier B.V. and the International Society of Chemotherapy....

  6. [First outbreak report of VIM-1 metallo-beta-lactamase producing Pseudomonas aeruginosa in Japan].

    Science.gov (United States)

    Miki, Kanji; Takegawa, Hiroshi; Etoh, Masaaki; Hayashi, Michio; Haruta, Tsunekazu; Yamane, Kunikazu; Arakawa, Yoshichika

    2010-11-01

    VIM-1 metallo-beta-lactamase (MBL) producing Pseudomonas aeruginosa was isolated from 35 Kobe City Medical Center General Hospital patients from September 2007 to July 2008. All but one were highly resistant to all beta-lactams, aminoglycoside, and fluoroquinolone, and one susceptible to amikacin. Strains negative to a disk diffusion screening test using sodium mercaptoacetate for detecting MBL numbered 35. PCR for MBL indicated all strains were positive for bla(VIWM-1). These strains were indistinguishable by pulsed-field gel electrophoresis, indicating an outbreak of infections caused by VIM-1 MBL producing Pseudomonas aeruginosa. After intervention to control contact, the outbreak was controlled. PMID:21226324

  7. Clinico-Microbiological Investigation of Catheter Associated Urinary Tract Infection by Enterococcus faecalis: vanA Genotype.

    Science.gov (United States)

    Padmavathy, Kesavaram; Praveen, Shabana; Madhavan, Radha; Krithika, Nagarajan; Kiruthiga, Alexander

    2015-08-01

    Prolonged hospitalization and exposure to third generation cephalosporins are reported to facilitate the acquisition and colonization of Vancomycin Resistant Enterococci (VRE). Though VRE is not uncommon in India, urinary tract infection with a vanA genotype is a cause of serious concern as VRE co-exhibit resistance to aminoglycosides. In India, majority of the VRE isolates recovered from hospitalized patients include Enterococcus faecium. We report a case of catheter associated urinary tract infection by an endogenous, multidrug resistant E. faecalis of vanA genotype following prolonged hospitalization, ICU stay, catheterisation and exposure to 3G cephalosporin and metronidazole. The patient responded to linezolid therapy. PMID:26435949

  8. Synthesis of heterocycles: Indolo (2,1-a) isoquinolines, renewables, and aptamer ligands for cellular imaging

    Energy Technology Data Exchange (ETDEWEB)

    Beasley, Jonathan [Ames Laboratory (AMES), Ames, IA (United States)

    2013-01-01

    In this thesis, we explore both total syntheses and methodologies of several aromatic heterocyclic molecules. Extensions of the Kraus indole synthesis toward 2-substituted and 2,3-disubstituted indoles, as well as biologically attractive indolo[2,1-a]isoquinolines are described. Recent renewable efforts directed to commodity maleic acid and the first reported furan-based ionic liquids are described. Our total synthesis of mRNA aptamer ligand PDC-Gly, and its dye coupled forms, plus aminoglycoside dye coupled ligands used in molecular imaging, are described.

  9. Soluble monomeric acetylcholinesterase from mouse: expression, purification, and crystallization in complex with fasciculin.

    OpenAIRE

    Marchot, P.; Ravelli, R. B.; Raves, M. L.; Bourne, Y.; Vellom, D. C.; Kanter, J.; Camp, S; Sussman, J. L.; Taylor, P

    1996-01-01

    A soluble, monomeric form of acetylcholinesterase from mouse (mAChE), truncated at its carboxyl-terminal end, was generated from a cDNA encoding the glycophospholipid-linked form of the mouse enzyme by insertion of an early stop codon at position 549. Insertion of the cDNA behind a cytomegalovirus promoter and selection by aminoglycoside resistance in transfected HEK cells yielded clones secreting large quantities of mAChE into the medium. The enzyme sediments as a soluble monomer at 4.8 S. H...

  10. Activation of the SOS response increases the frequency of small colony variants

    DEFF Research Database (Denmark)

    Vestergaard, Martin; Paulander, Wilhelm Erik Axel; Ingmer, Hanne

    2015-01-01

    different mechanism of action influence the formation of SCVs that are resistant to otherwise lethal concentrations of the aminoglycoside, gentamicin. We found that exposure of S. aureus to fluoroquinolones and mitomycin C increased the frequency of gentamicin resistant SCVs, while other antibiotic classes...... failed to do so. The higher proportion of SCVs in cultures exposed to fluoroquinolones and mitomycin C compared to un-exposed cultures correlate with an increased mutation rate monitored by rifampicin resistance and followed induction of the SOS DNA damage response. CONCLUSION: Our observations suggest...

  11. INTERACTIVE EFFECTS OF DIFFERENT DURATION OF LITHIUM PRETREATMENT WITH AMIKACIN AND GENTAMICIN ONAPOMORPHINE-INDUCED LICKING IN RATS

    OpenAIRE

    MOHAMMAD SHARIFZADEH; ELHAM KHAJVAND-FIROOZ; MOHAMMAD ABDOLLAHI

    2000-01-01

    In this study the hypothesis that aminoglycoside antibiotics and lithium may influence apomorphine-induced licking via their effects on phosphoinositide pathways and calcium stores were investigated in male rats. Subcutaneous administration of apomorphine (0.1,0.25 and 0.5 mg/kg) to rats induced licking in a dose-dependent manner and the maximum response was obtained by the dose of 0.5 mg/kg of the drug. Intracerebroventricular injections of amikacin (5, 25 and 50 ug/rat) and gentamicin (10, ...

  12. Construction of Yeast Vectors with Resistance to Geneticin

    Institute of Scientific and Technical Information of China (English)

    林会兰; 张广; 周全; 陈国强

    2002-01-01

    Two Escherichia coli-Saccharomyces cerevisiae shuttle vectors containing a resistance marker to geneticin (G418) are constructed. Both vectors contain a kanamycin-resistant marker (KanMX4) module coding aminoglycoside 3'-phosphotransferase (APH) that renders E. coli resistant to kanamycin and S. cerevisiae to geneticin. These vectors overcome the shortage of the conventional yeast vectors bearing HIS3, TRP1, LEU2, and URA3 modules as selection markers, which require hosts to be auxotrophic. Green fluorescent protein (GFP) is used as the reporter to examine the functions of the vectors. The vectors are powerful tools for the convenient cloning and controlled expression of genes in most S. cerevisiae strains.

  13. Microvascular Complications in Cystic Fibrosis-Related Diabetes Mellitus: a Case Report.

    Directory of Open Access Journals (Sweden)

    Scott AIR

    2000-11-01

    Full Text Available CONTEXT, The prevalence of cystic fibrosis-related diabetes mellitus is increasing and is associated with increased survival from cystic fibrosis. CASE REPORT, This study describes a case of the premature onset of disabling and widespread microvascular complications resulting from cystic fibrosis-related diabetes mellitus. Previously asymptomatic retinopathy was diagnosed on recognition of diabetic nephropathy. CONCLUSIONS, The treatment of pulmonary exacerbations has become more complex due to the nephrotoxic potential of intravenous aminoglycoside drugs which are frequently used to control chronic Pseudomonas infection in cystic fibrosis.

  14. AN IMPORTED CASE OF ACUTE MELIOIDOSIS CAUSED BY ST881 BURKHOLDERIA PSEUDOMALLEI.

    Science.gov (United States)

    Zong, Zhiyong; Wang, Xiaohui; Deng, Yiyun

    2016-03-01

    A previously healthy Chinese male working in Malaysia returned to China with high fever. A blood culture showed Burkholderia pseudomallei strain WCBP1. This isolate was sequenced, showing type, ST881, which appears to be present in Malaysia. WCP1 had unusual susceptibility to aminoglycosides and habored the Yersinia-like fimbrial gene cluster for virulence. The patient's condition deteriorated rapidly but he recovered after receiving meropenem and intensive care support. Melioidosis is a potential problem among Chinese imigrant workers with strains new to China being identified. PMID:27244959

  15. Unusual association of NDM-1 with KPC-2 and armA among Brazilian Enterobacteriaceae isolates

    Directory of Open Access Journals (Sweden)

    M.G. Quiles

    2015-02-01

    Full Text Available We report the microbiological characterization of four New Delhi metallo-β-lactamase-1 (blaNDM-1-producing Enterobacteriaceae isolated in Rio de Janeiro, Brazil. blaNDM-1 was located on a conjugative plasmid and was associated with Klebsiella pneumoniae carbapenemase-2 (blaKPC-2 or aminoglycoside-resistance methylase (armA, a 16S rRNA methylase not previously reported in Brazil, in two distinct strains of Enterobacter cloacae. Our results suggested that the introduction of blaNDM-1 in Brazil has been accompanied by rapid spread, since our isolates showed no genetic relationship.

  16. First Description of Two Sequence Type 2 Acinetobacter baumannii Isolates Carrying OXA-23 Carbapenemase in Pagellus acarne Fished from the Mediterranean Sea near Bejaia, Algeria.

    Science.gov (United States)

    Brahmi, Soumia; Touati, Abdelaziz; Cadière, Axelle; Djahmi, Nassima; Pantel, Alix; Sotto, Albert; Lavigne, Jean-Philippe; Dunyach-Remy, Catherine

    2016-04-01

    To determine the occurrence of carbapenem-resistantAcinetobacter baumanniiin fish fished from the Mediterranean Sea near the Bejaia coast (Algeria), we studied 300 gills and gut samples that had been randomly and prospectively collected during 1 year. After screening on selective agar media, using PCR arrays and whole-genome sequencing, we identified for the first time two OXA-23-producingA. baumanniistrains belonging to the widespread sequence type 2 (ST2)/international clone II and harboring aminoglycoside-modifying enzymes [aac(6')-Ib andaac(3')-I genes]. PMID:26787693

  17. PREVALENCE OF ENTEROCOCCAL INFECTIONS AND THEIR ANTIBIOTIC SUSCEPTIBILITY PATTERN WITH SPECIAL REFERENCE TO HLAR IN SOUTH EAST RAJASTHAN

    Directory of Open Access Journals (Sweden)

    Vasudev

    2016-04-01

    Full Text Available BACKGROUND Enterococci are Gram positive bacteria, which mainly form gastrointestinal flora. Enterococcus has consistently ranked among the most frequent pathogen causing significant hospital-acquired infections. They were classified as group D streptococci. Clinically, the most important species associated with human infections are E. faecalis and E. faecium. Enterococcus develops acquired resistance to several classes of antibiotics either by mutation or by transfer of plasmids and transposons. The acquisition of highlevel aminoglycoside resistance and vancomycin resistance limits the therapeutic options available for clinicians. The present study was undertaken to determine the antimicrobial susceptibility pattern of the Enterococcus spp. with special reference to High Level Aminoglycoside Resistance (HLAR. MATERIAL AND METHODS The present study was done at tertiary care health centre in South East Rajasthan. A total of 100 isolates taken from both OPD and IPD patients for a period of one year are included in the study. RESULTS A total 100 isolates of Enterococcus from various clinical samples were taken for the current study. In the current study seven species were identified which are E. faecalis, E. faecium, E. raffinosus, E. durans, E. mundtii, E. gallinarum, and E. solitarius. Among all the species, E. faecalis (57 was the predominant isolate in all the samples followed by E. faecium (33, E. raffinosus (4, E. durans and E. mundtii (2 each, E. gallinarum and E. solitarius (1 each. CONCLUSION Enterococcal infections are difficult to treat, as this bacterium has intrinsic resistance to various antibiotics and also can acquire resistance against other antibiotics available for treatment. In the case of complicated Enterococcus infection combination of cephalosporin and aminoglycoside are usually used, but in High Level Aminoglycoside Resistance (HLAR even this combination is unable to inhibit the organism. So it is important to test

  18. Recurrent Chronic Ambulatory Peritoneal Dialysis-Associated Infection due to Rothia dentocariosa

    Directory of Open Access Journals (Sweden)

    Shaun K Morris

    2004-01-01

    Full Text Available Rothia dentocariosa is a commensal organism of the human oropharynx. Clinical infection due to this organism is rare. A case of recurrent peritoneal dialysis-related peritonitis caused by R dentocariosa and a review of the literature is reported. Isolation of R dentocariosa from dialysate fluid should not be dismissed as a contaminant. Although there are no interpretive criteria for antimicrobial susceptibility testing, R dentocariosa appears to be susceptible to a variety of antibiotics including beta-lactams, vancomycin and aminoglycosides. Optimal therapy of peritoneal dialysis peritonitis caused by this organism may also require removal of the catheter.

  19. Impact of pH and cationic supplementation on in vitro postantibiotic effect.

    OpenAIRE

    Gudmundsson, A.; Erlendsdottir, H; Gottfredsson, M; Gudmundsson, S.

    1991-01-01

    Most studies on pharmacodynamic variables in vitro, including the postantibiotic effect (PAE), are performed at pH 7.4 in noncationic-supplemented media, a situation which may differ significantly from the true microenvironment in most infected foci. We studied the impact of five different pH levels (pH 5, 6, 7, 7.4, and 8) on the duration of the PAE, the MIC, and bactericidal activity. Acid pH was found to have in general a deleterious effect on the activity of aminoglycosides and ciprofloxa...

  20. Can carbapenem-resistant enterobacteriaceae susceptibility results obtained from surveillance cultures predict the susceptibility of a clinical carbapenem-resistant enterobacteriaceae?

    Science.gov (United States)

    Perez, Leandro Reus Rodrigues; Rodrigues, Diógenes; Dias, Cícero

    2016-08-01

    We evaluated the susceptibility profile of a colonizing carbapenem-resistant enterobacteriaceae to predict its susceptibility when recovered from a clinical specimen. An overall agreement of 88.7% (517 out of 583; 95% confidence interval, 85.8%-91.0%) was observed for the combinations of 11 antibiotics with 53 pairs of Klebsiella pneumoniae carbapenemase-producing K pneumoniae (the only carbapenem-resistant enterobacteriaceae detected). Very major errors were observed mainly for aminoglycoside agents and colistin, limiting the predictability of the susceptibility profile for these clinical isolates. PMID:27021509

  1. Magnetic isotope effect of magnesium (25)Mg on E. coli resistance to antibiotics.

    Science.gov (United States)

    Letuta, U G; Vekker, A S; Kornilova, T A; Gryaznov, A A; Cheplakov, I A

    2016-07-01

    Effects of synergism and antagonism of antibacterial drugs and magnetic isotope of magnesium (25)Mg on antibiotic resistance of bacteria E. coli were discovered. Fourteen antibiotics from seven different groups were tested. The increase in antibiotic resistance in the presence of the ion (25)Mg(2+) was discovered in E. coli cells incubated with quinolones/fluoroquinolones, indicating the inhibiting effect of the magnetic moments of nuclei (25)Mg on DNA synthesis. The change in antibiotic resistance was also detected in bacteria affected by magnesium (25)Mg and certain antibiotics from aminoglycoside and lincosamide groups. PMID:27599512

  2. Drug-resistant genes carried by Acinetobacter baumanii isolated from patients with lower respiratory tract infection

    Institute of Scientific and Technical Information of China (English)

    DAI Ning; ZHANG Wei; LI Jia-shu; YU Qin; WAN Huan-ying; MU Lan; ZHONG Xiao-ning; WEI Li-ping; MA Jian-jun; WANG Qiu-yue; HU Ke; LI De-zhi; TIAN Gui-zhen; CAI Shao-xi; WANG Rui-qin; HE Bei; WANG Si-qin; WANG Zhan-wei; ZHAO Su-rui; GAO Zhan-cheng; CHEN Ji-chao; CHEN Yu-sheng; GENG Rong; HU Ying-hui; YANG Jing-ping; DU Juan; HU Cheng-ping

    2010-01-01

    Background Acinetobacter baumanii (A. baumanii) remains an important microbial pathogen resulting in nosocomial acquired infections with significant morbidity and mortality. The mechanism by which nosocomial bacteria, like A.baumanii, attain multidrug resistance to antibiotics is of considerable interest. The aim in this study was to investigate the spread status of antibiotic resistance genes, such as multiple β-lactamase genes and aminoglycoside-modifying enzyme genes, from A. baumanii strains isolated from patients with lower respiratory tract infections (LRTIs).Methods Two thousand six hundred and ninety-eight sputum or the bronchoalveolar lavage samples from inpatients with LRTIs were collected in 21 hospitals in the mainland of China from November 2007 to February 2009. All samples were routinely inoculated. The isolated bacterial strains and their susceptibility were analyzed via VITEK-2 expert system.Several kinds of antibiotic resistant genes were further differentiated via polymerase chain reaction and sequencing methods.Results Totally, 39 A. baumanii strains were isolated from 2698 sputum or bronchoalveolar lavage samples. There was not only a high resistant rate of the isolated A. baumanii strains to ampicillin and first- and second-generation cephalosporins (94.87%, 100% and 97.44%, respectively), but also to the third-generation cephalosporins (ceftriaxone at 92.31%, ceftazidine at 51.28%) and imipenem (43.59%) as well. The lowest antibiotic resistance rate of 20.51% was found to amikacin. The OXA-23 gene was identified in 17 strains of A. baumanii, and the AmpC gene in 23 strains. The TEM-1 gene was carried in 15 strains. PER-1 and SHV-2 genes were detected in two different strains.Aminoglycoside-modifying enzyme gene aac-3-la was found in 23 strains, and the aac-6'-lb gene in 19 strains, aac-3-la and aac-6'-lb genes hibernated in three A. baumanii strains that showed no drug-resistant phenotype.Conclusions A. baumaniican carry multiple drug

  3. Combination Therapy of Sophoraflavanone B against MRSA: In Vitro Synergy Testing

    Directory of Open Access Journals (Sweden)

    Su-Hyun Mun

    2013-01-01

    Full Text Available Sophoraflavanone B (SPF-B, a known prenylated flavonoid, was isolated from the roots of Desmodium caudatum. The aim of this study was to determine the antimicrobial synergism of SPF-B combined with antibiotics against methicillin-resistant Staphylococcus aureus (MRSA. MRSA, a multidrug-resistant pathogen, causes both hospital- and community-acquired infections worldwide. The antimicrobial activity of SPF-B was assessed by the broth microdilution method, checkerboard dilution test, and time-kill curve assay. The MIC of SPF-B for 7 strains of S. aureus ranges from 15.6 to 31.25 μg/mL determined. In the checkerboard method, the combinations of SPF-B with antibiotics had a synergistic effect; SPF-B markedly reduced the MICs of the β-lactam antibiotics: ampicillin (AMP and oxacillin (OXI; aminoglycosides gentamicin (GET; quinolones ciprofloxacin (CIP and norfloxacin (NOR against MRSA. The time-kill curves assay showed that a combined SPF-B and selected antibiotics treatment reduced the bacterial counts below the lowest detectable limit after 24 h. These data suggest that the antibacterial activity of SPF-B against MRSA can be effectively increased through its combination with three groups of antibiotics (β-lactams, aminoglycosides, and quinolones. Our research can be a valuable and significant source for the development of a new antibacterial drug with low MRSA resistance.

  4. Geldanamycin induces production of heat shock protein 70 and partially attenuates ototoxicity caused by gentamicin in the organ of Corti explants

    Directory of Open Access Journals (Sweden)

    Haupt Heidemarie

    2009-09-01

    Full Text Available Abstract Background Heat shock protein 70 (HSP70 protects inner ear cells from damage and death induced by e.g. heat or toxins. Benzoquinone ansamycin antibiotic geldanamycin (GA was demonstrated to induce the expression of HSP70 in various animal cell types. The aim of our study was to investigate whether GA induces HSP70 in the organ of Corti (OC, which contains the auditory sensory cells, and whether GA can protect these cells from toxicity caused by a common aminoglycoside antibiotic gentamicin. Methods To address these questions, we used the OC explants isolated from p3-p5 rats. As a read-out, we used RT-PCR, ELISA and immunofluorescence. Results We found that GA at the concentration of 2 μM efficiently induced HSP70 expression on mRNA and protein level in the OC explants. Confocal microscopy revealed that HSP70 induced by GA is expressed by hair cells and interdental cells of spiral limbus. Preincubation of explants with 2 μM GA prior to adding gentamicin (500 μM significantly reduced the loss of outer but not inner hair cells, suggesting different mechanisms of otoprotection needed for these two cell types. Conclusion GA induced HSP70 in the auditory sensory cells and partially protected them from toxicity of gentamicin. Understanding the molecular mechanisms of GA otoprotection may provide insights for preventative therapy of the hearing loss caused by aminoglycoside antibiotics.

  5. Optimising dosing strategies of antibacterials utilising pharmacodynamic principles: impact on the development of resistance.

    Science.gov (United States)

    DeRyke, C Andrew; Lee, Su Young; Kuti, Joseph L; Nicolau, David P

    2006-01-01

    Evolving antimicrobial resistance is of global concern. The impact of decreased susceptibility to current antibacterials coupled with the decline in the marketing of new agents with novel mechanisms of action places a tremendous burden on clinicians to appropriately use available agents. Optimising antibacterial dose administration through the use of pharmacodynamic principles can aid clinicians in accomplishing this task more effectively. Methods to achieve this include: continuous or prolonged infusion, or the use of smaller doses administered more frequently for the time-dependent beta-lactam agents; or higher, less frequent dose administration of the concentration-dependent aminoglycosides and fluoroquinolones. Pharmacodynamic breakpoints, which are predictive of clinical and/or microbiological success in the treatment of infection, have been determined for many classes of antibacterials, including the fluoroquinolones, aminoglycosides and beta-lactams. Although surpassing these values may predict efficacy, it may not prevent the development of resistance. Recent studies seek to determine the pharmacodynamic breakpoints that prevent the development of resistance. Numerous studies to this point have determined these values in fluoroquinolones in both Gram-positive and Gram-negative bacteria. However, among the other antibacterial classes, there is a lack of sufficient data. Additionally, a new term, the mutant prevention concentration, has been based on the concentrations above which resistance is unlikely to occur. Future work is needed to fully characterise these target concentrations that prevent resistance. PMID:16398565

  6. Modulatory antibacterial activity of body fat from Gallus gallus domesticus (Linnaeus 1758

    Directory of Open Access Journals (Sweden)

    Henrique Coutinho

    2014-12-01

    Full Text Available Based on the popular belief ,which uses fat from G. g. domesticus. (domestic chicken, to combat infectious and inflammatory processes, this work aims to evaluate the antibacterial action of lipids in adipose tissue of these animals besides verifying association with antibiotics observing the modulating effect of natural products against standard strains of Staphylococcus aureus and Escherichia coli and multiresistant of Staphylococcus aureus from clinical isolates. We evaluated the antibacterial activity of the samples, determining the minimum inhibitory concentration(MIC by microdilution method. And after testing was conducted to verify the possible synergistic action between the samples and the antimicrobials using fat tissues in a sub inhibitory concentration.The interactions of aminoglycosides with the samples at concentrations of 128g /ml(MIC1/8were effective against S.aureos 358,and amikacin activity associated with the TAGCc with most representative reduction from 64 to 8μg/mL. The results of this study indicate that the TAGc and TAGi are an alternative source of natural products with antibacterial action, as possible to potentiate the activity of aminoglycosides against the strains of S.aureus 358. Both deserving continuing to elucidate the antimicrobial and toxicological action.

  7. Aquaculture changes the profile of antibiotic resistance and mobile genetic element associated genes in Baltic Sea sediments.

    Science.gov (United States)

    Muziasari, Windi I; Pärnänen, Katariina; Johnson, Timothy A; Lyra, Christina; Karkman, Antti; Stedtfeld, Robert D; Tamminen, Manu; Tiedje, James M; Virta, Marko

    2016-04-01

    Antibiotics are commonly used in aquaculture and they can change the environmental resistome by increasing antibiotic resistance genes (ARGs). Sediment samples were collected from two fish farms located in the Northern Baltic Sea, Finland, and from a site outside the farms (control). The sediment resistome was assessed by using a highly parallel qPCR array containing 295 primer sets to detect ARGs, mobile genetic elements and the 16S rRNA gene. The fish farm resistomes were enriched in transposon and integron associated genes and in ARGs encoding resistance to antibiotics which had been used to treat fish at the farms. Aminoglycoside resistance genes were also enriched in the farm sediments despite the farms not having used aminoglycosides. In contrast, the total relative abundance values of ARGs were higher in the control sediment resistome and they were mainly genes encoding efflux pumps followed by beta-lactam resistance genes, which are found intrinsically in many bacteria. This suggests that there is a natural Baltic sediment resistome. The resistome associated with fish farms can be from native ARGs enriched by antibiotic use at the farms and/or from ARGs and mobile elements that have been introduced by fish farming. PMID:26976842

  8. New inducible genetic method reveals critical roles of GABA in the control of feeding and metabolism.

    Science.gov (United States)

    Meng, Fantao; Han, Yong; Srisai, Dollada; Belakhov, Valery; Farias, Monica; Xu, Yong; Palmiter, Richard D; Baasov, Timor; Wu, Qi

    2016-03-29

    Currently available inducibleCre/loxPsystems, despite their considerable utility in gene manipulation, have pitfalls in certain scenarios, such as unsatisfactory recombination rates and deleterious effects on physiology and behavior. To overcome these limitations, we designed a new, inducible gene-targeting system by introducing an in-frame nonsense mutation into the coding sequence of Cre recombinase (nsCre). Mutant mRNAs transcribed fromnsCretransgene can be efficiently translated into full-length, functional Cre recombinase in the presence of nonsense suppressors such as aminoglycosides. In a proof-of-concept model, GABA signaling from hypothalamic neurons expressing agouti-related peptide (AgRP) was genetically inactivated within 4 d after treatment with a synthetic aminoglycoside. Disruption of GABA synthesis in AgRP neurons in young adult mice led to a dramatic loss of body weight due to reduced food intake and elevated energy expenditure; they also manifested glucose intolerance. In contrast, older mice with genetic inactivation of GABA signaling by AgRP neurons had only transient reduction of feeding and body weight; their energy expenditure and glucose tolerance were unaffected. These results indicate that GABAergic signaling from AgRP neurons plays a key role in the control of feeding and metabolism through an age-dependent mechanism. This new genetic technique will augment current tools used to elucidate mechanisms underlying many physiological and neurological processes. PMID:26976589

  9. Netilmicin. A review of its antibacterial activity, pharmacokinetic properties and therapeutic use.

    Science.gov (United States)

    Campoli-Richards, D M; Chaplin, S; Sayce, R H; Goa, K L

    1989-11-01

    Netilmicin is a semisynthetic aminoglycoside derived from sisomicin. It is active against most Gram-negative and some Gram-positive bacteria, including many gentamicin-resistant strains. Netilmicin has proved to be effective in Gram-negative infections of the urinary tract, skin and skin structure, and lower respiratory tract, as well as in intra-abdominal infections, septicaemia and other miscellaneous infections. In some trials, the more easily implemented once daily administration of netilmicin has been as effective as multiple dosing regimens. However, further investigation is required to confirm that efficacy and safety are not compromised with once daily administration. Comparative studies have generally revealed similar clinical and bacteriological efficacies between netilmicin and gentamicin, amikacin or tobramycin. As with other aminoglycosides, the principal adverse effects of netilmicin are nephrotoxicity and ototoxicity. Although animal studies strongly suggest that these are less common with netilmicin than with related drugs, there appears to be no difference in their incidence in clinical use; in clinical trials the incidence of nephrotoxicity and ototoxicity has been low, with the symptoms in many cases being minor and reversible. Netilmicin is, therefore, an effective antibacterial drug for the parenteral treatment of severe infections, offering theoretical advantages in safety which may indicate its use for patients believed to be at risk of adverse effects. PMID:2689137

  10. Prevalence and bacterial susceptibility of hospital acquired urinary tract infection

    Directory of Open Access Journals (Sweden)

    Dias Neto José Anastácio

    2003-01-01

    Full Text Available PURPOSE: Urinary tract infection is the most common nosocomially acquired infection. It is important to know the etiology and antibiotic susceptibility infectious agents to guide the initial empirical treatment. OBJECTIVE: To determine the prevalence of bacterial strains and their antibiotic susceptibility in nosocomially acquired urinary tract infection in a university hospital between January and June 2003. METHODS: We analyzed the data of 188 patients with positive urine culture (= 10(5 colony-forming units/mL following a period of 48 hours after admission. RESULTS: Half of patients were male. Mean age was 50.26 ± 22.7 (SD, range 3 months to 88 years. Gram-negative bacteria were the agent in approximately 80% of cases. The most common pathogens were E. coli (26%, Klebsiella sp. (15%, P. aeruginosa (15% and Enterococcus sp. (11%. The overall bacteria susceptibility showed that the pathogens were more sensible to imipenem (83%, second or third generation cephalosporin and aminoglycosides; and were highly resistant to ampicillin (27% and cefalothin (30%. It is important to note the low susceptibility to ciprofloxacin (42% and norfloxacin (43%. CONCLUSION: This study suggests that if one can not wait the results of urine culture, the best choices to begin empiric treatment are imipenem, second or third generation cephalosporin and aminoglycosides. Cefalothin and ampicillin are quite ineffective to treat these infections.

  11. Practices related to late-onset sepsis in very low-birth weight preterm infants

    Directory of Open Access Journals (Sweden)

    Maria Regina Bentlin

    2015-04-01

    Full Text Available OBJECTIVE: To understand the practices related to late-onset sepsis (LOS in the centers of the Brazilian Neonatal Research Network, and to propose strategies to reduce the incidence of LOS. METHODS: This was a cross-sectional descriptive multicenter study approved by the Ethics Committee. Three questionnaires regarding hand hygiene, vascular catheters, and diagnosis/treatment of LOS were sent to the coordinator of each center. The center with the lowest incidence of LOS was compared with the others. RESULTS: All 16 centers answered the questionnaires. Regarding hand hygiene, 87% use chlorhexidine or 70% alcohol; alcohol gel is used in 100%; 80% use bedside dispensers (50% had one dispenser for every two beds; practical training occurs in 100% and theoretical training in 70% of the centers, and 37% train once a year. Catheters: 94% have a protocol, and 75% have a line insertion team. Diagnosis/treatment: complete blood count and blood culture are used in 100%, PCR in 87%, hematological scores in 75%; oxacillin and aminoglycosides is the empirical therapy in 50% of centers. Characteristics of the center with lowest incidence of LOS: stricter hand hygiene; catheter insertion and maintenance groups; use of blood culture, PCR, and hematological score for diagnosis; empirical therapy with oxacillin and aminoglycoside. CONCLUSION: The knowledge of the practices of each center allowed for the identification of aspects to be improved as a strategy to reduce LOS, including: alcohol gel use, hand hygiene training, implementation of catheter teams, and wise use of antibiotic therapy.

  12. Van ‘t Hoff global analyses of variable temperature isothermal titration calorimetry data

    International Nuclear Information System (INIS)

    Highlights: ▶ We developed a global fitting strategy for ITC data collected at multiple temperatures. ▶ This method does not require prior knowledge of the binding mechanism. ▶ Monte Carlo simulations show that the approach improves the accuracy of extracted thermodynamic parameters. ▶ The method is used to study coupled folding/binding in aminoglycoside 6′-N-acetyltransferase-Ii. - Abstract: Isothermal titration calorimetry (ITC) can provide detailed information on the thermodynamics of biomolecular interactions in the form of equilibrium constants, KA, and enthalpy changes, ΔHA. A powerful application of this technique involves analyzing the temperature dependences of ITC-derived KA and ΔHA values to gain insight into thermodynamic linkage between binding and additional equilibria, such as protein folding. We recently developed a general method for global analysis of variable temperature ITC data that significantly improves the accuracy of extracted thermodynamic parameters and requires no prior knowledge of the coupled equilibria. Here we report detailed validation of this method using Monte Carlo simulations and an application to study coupled folding and binding in an aminoglycoside acetyltransferase enzyme.

  13. Occurrence of the aacA4 gene among multidrug resistant strains of Pseudomonas aeruginosa isolated from bronchial secretions obtained from the Intensive Therapy Unit at University Hospital in Bialystok, Poland

    Directory of Open Access Journals (Sweden)

    Paweł Sacha

    2012-07-01

    Full Text Available The aim of this study was to investigate the prevalence of the aacA4 gene in a population of multidrug resistant strains of P. aeruginosa isolated from bronchial secretions obtained from the Intensive Therapy Unit (ITU. Twelve MDR isolates were tested for antibiotic susceptibility and the presence of the aacA4 gene. In this study, 58.3% of the strains contained (6’-Ib’ aminoglycoside acetyltransferase gene. All of the studied strains (aacA4-positive and aacA4-negative were susceptible only to colistine (100%. Among other antibiotics, the lowest resistance rates were those shown against ceftazidime (14.3% to 20% and imipenem (28.6% to 40%. Our studies frequently revealed the presence of the aacA4 gene as a factor responsible for resistance; it is probable that other mechanisms of resistance to aminoglycoside antibiotics also occurred.

  14. Van 't Hoff global analyses of variable temperature isothermal titration calorimetry data

    Energy Technology Data Exchange (ETDEWEB)

    Freiburger, Lee A.; Auclair, Karine [Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6 (Canada); Mittermaier, Anthony K., E-mail: anthony.mittermaier@mcgill.ca [Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6 (Canada)

    2012-01-10

    Highlights: Black-Right-Pointing-Triangle We developed a global fitting strategy for ITC data collected at multiple temperatures. Black-Right-Pointing-Triangle This method does not require prior knowledge of the binding mechanism. Black-Right-Pointing-Triangle Monte Carlo simulations show that the approach improves the accuracy of extracted thermodynamic parameters. Black-Right-Pointing-Triangle The method is used to study coupled folding/binding in aminoglycoside 6 Prime -N-acetyltransferase-Ii. - Abstract: Isothermal titration calorimetry (ITC) can provide detailed information on the thermodynamics of biomolecular interactions in the form of equilibrium constants, K{sub A}, and enthalpy changes, {Delta}H{sub A}. A powerful application of this technique involves analyzing the temperature dependences of ITC-derived K{sub A} and {Delta}H{sub A} values to gain insight into thermodynamic linkage between binding and additional equilibria, such as protein folding. We recently developed a general method for global analysis of variable temperature ITC data that significantly improves the accuracy of extracted thermodynamic parameters and requires no prior knowledge of the coupled equilibria. Here we report detailed validation of this method using Monte Carlo simulations and an application to study coupled folding and binding in an aminoglycoside acetyltransferase enzyme.

  15. Novel, Synergistic Antifungal Combinations that Target Translation Fidelity.

    Science.gov (United States)

    Moreno-Martinez, Elena; Vallieres, Cindy; Holland, Sara L; Avery, Simon V

    2015-01-01

    There is an unmet need for new antifungal or fungicide treatments, as resistance to existing treatments grows. Combination treatments help to combat resistance. Here we develop a novel, effective target for combination antifungal therapy. Different aminoglycoside antibiotics combined with different sulphate-transport inhibitors produced strong, synergistic growth-inhibition of several fungi. Combinations decreased the respective MICs by ≥8-fold. Synergy was suppressed in yeast mutants resistant to effects of sulphate-mimetics (like chromate or molybdate) on sulphate transport. By different mechanisms, aminoglycosides and inhibition of sulphate transport cause errors in mRNA translation. The mistranslation rate was stimulated up to 10-fold when the agents were used in combination, consistent with this being the mode of synergistic action. A range of undesirable fungi were susceptible to synergistic inhibition by the combinations, including the human pathogens Candida albicans, C. glabrata and Cryptococcus neoformans, the food spoilage organism Zygosaccharomyces bailii and the phytopathogens Rhizoctonia solani and Zymoseptoria tritici. There was some specificity as certain fungi were unaffected. There was no synergy against bacterial or mammalian cells. The results indicate that translation fidelity is a promising new target for combinatorial treatment of undesirable fungi, the combinations requiring substantially decreased doses of active components compared to each agent alone. PMID:26573415

  16. Impact of metal ions on netilmicin-melanin interaction.

    Science.gov (United States)

    Wrześniok, Dorota; Buszman, Ewa; Grzegorczyk, Magdalena; Grzegorczyk, Aneta; Hryniewicz, Tomasz

    2012-01-01

    Netilmicin, which is mainly used as the sulfate, is a semisynthetic, water soluble aminoglycoside antibiotic obtained by chemical modification of sisomicin. It is active against both Gram-positive and Gram-negative bacteria, including strains which are resistant to other aminoglycosides. Netilmicin form complexes with melanin. The aim of the presented work was to examine the effect of Cu2+, Zn2+, Ca2+ and Mg2+ on netilmicin binding to synthetic DOPA-melanin. It has been demonstrated that metal ions decrease the amount of antibiotic bound to melanin as compared with netilmicin-melanin complexes obtained in the absence of metals. It has been also shown that only one class of binding sites participates in netilmicin-[melanin-metal ion] complexes formation with the association constant K approximately 10(3) M(-1). The obtained results demonstrate that Cu2+, Zn2+, Ca2+ and Mg2+ ions modify the interaction between netilmicin and melanin biopolymer. The blocking of some active centers in melanin molecules by metal ions, which potentially exist in living systems, may influence the clinical therapeutic efficiency as well as the undesirable side effects of netilmicin. PMID:22574505

  17. Heavy metals in liquid pig manure in light of bacterial antimicrobial resistance

    International Nuclear Information System (INIS)

    Heavy metals are regularly found in liquid pig manure, and might interact with bacterial antimicrobial resistance. Concentrations of heavy metals were determined by atomic spectroscopic methods in 305 pig manure samples and were connected to the phenotypic resistance of Escherichia coli (n=613) against 29 antimicrobial drugs. Concentrations of heavy metals (/kg dry matter) were 0.08–5.30 mg cadmium, 1.1–32.0 mg chrome, 22.4–3387.6 mg copper, <2.0–26.7 mg lead, <0.01–0.11 mg mercury, 3.1–97.3 mg nickel and 93.0–8239.0 mg zinc. Associated with the detection of copper and zinc, resistance rates against β-lactams were significantly elevated. By contrast, the presence of mercury was significantly associated with low antimicrobial resistance rates of Escherichia coli against β-lactams, aminoglycosides and other antibiotics. Effects of subinhibitory concentrations of mercury on bacterial resistance against penicillins, cephalosporins, aminoglycosides and doxycycline were also demonstrated in a laboratory trial. Antimicrobial resistance in the porcine microflora might be increased by copper and zinc. By contrast, the occurrence of mercury in the environment might, due to co-toxicity, act counter-selective against antimicrobial resistant strains.

  18. Adverse drug reaction and toxicity caused by commonly used antimicrobials in canine practice

    Directory of Open Access Journals (Sweden)

    K. Arunvikram

    2014-05-01

    Full Text Available An adverse drug reaction (ADR is a serious concern for practicing veterinarians and other health professionals, and refers to an unintended, undesired and unexpected response to a drug that negatively affects the patient's health. It may be iatrogenic or genetically induced, and may result in death of the affected animal. The ADRs are often complicated and unexpected due to myriad clinical symptoms and multiple mechanisms of drug-host interaction. Toxicity due to commonly used drugs is not uncommon when they are used injudiciously or for a prolonged period. Licosamides, exclusively prescribed against anaerobic pyoderma, often ends with diarrhoea and vomiting in canines. Treatment with Penicillin and β-lactam antibiotics induces onset of pemphigious vulgare, drug allergy or hypersensitivity. Chloroamphenicol and aminoglycosides causes Gray's baby syndrome and ototoxicity in puppies, respectively. Aminoglycosides are very often associated with nephrotoxicity, ototoxicity and neuromuscular blockage. Injudicious use of fluroquinones induces the onset of arthropathy in pups at the weight bearing joints. The most effective therapeutic measure in managing ADR is to treat the causative mediators, followed by supportive and symptomatic treatment. So, in this prospective review, we attempt to bring forth the commonly occurring adverse drug reactions, their classification, underlying mechanism, epidemiology, treatment and management as gleaned from the literature available till date and the different clinical cases observed by the authors.

  19. Frequency and Susceptibility of Bacteria Caused Urinary Tract Infection in Neonates: Eight-Year Study at Neonatal Division of Bahrami Children's Hospital, Tehran Iran.

    Directory of Open Access Journals (Sweden)

    Peymaneh Alizadeh Taheri

    2013-10-01

    Full Text Available Susceptibility pattern of organisms causing urinary tract infection (UTI in neonate would potentially improve the clinical management by enabling clinicians to choose most reasonable first line empirical antibiotics. This study aimed to this end by studying isolated organisms from neonates with UTI in an inpatient setting.Current retrospective study has recruited all cases of neonatal UTI diagnosed through a suprapubic/catheterized sample, admitted to Neonatal Division of Bahrami Children's Hospital, Tehran, Iran, from June 2004 to June 2012.Escherichia coli was the dominant (64.4% bacteria among a total of 73 cases (69.9% boys and 30.1% girls; aged 14.14 ± 7.68 days; birth weight of 3055.85 ± 623.00 g and Enterobacter (19.2%, Klebsiella (12.3%, and Staphylococcus epidermdisis (4.1% were less frequent isolated bacteria. E. coli was mostly resistant to ampicillin (93.6%, cefixime (85.7% and cephalexin (77.3%, and sensitive to cefotaxime (63.6%. Enterobacter found to be most resistant to amikacin (100%, ampicillin (92.85%, and most sensitive to ceftizoxime (71.4%.A high ratio (> 92.85% of resistance toward ampicillin was observed among common neonatal UTI bacterial agents. Having this finding along with previous reports of emerging resistance of neonatal uropathogensto ampicillin could be a notion that a combination of a third generation cephalosporin and an aminoglycoside would be a more reasonable first choice than ampicillin plus an aminoglycoside.

  20. Antibacterial activity of liposomal gentamicin against Pseudomonas aeruginosa: a time-kill study.

    Science.gov (United States)

    Rukholm, Gavin; Mugabe, Clement; Azghani, Ali O; Omri, Abdelwahab

    2006-03-01

    Cystic fibrosis (CF) is a common and lethal genetic disorder with a carrier frequency of 1 in 29 Caucasians. Chronic respiratory infections with Pseudomonas aeruginosa are the leading cause of morbidity and mortality in individuals with CF. Aminoglycoside antibiotics, including gentamicin, are highly effective against P. aeruginosa, but severe toxicity limits their use. One potential strategy for avoiding this problem is to encapsulate aminoglycosides in liposomes. In this study, we compared the bactericidal capacity of liposome-encapsulated gentamicin with that of free antibiotic against clinical isolates of P. aeruginosa. Liposome size, encapsulation efficiency and minimal inhibitory concentrations (MICs) of the free and liposomal gentamicin against gentamicin-sensitive and -resistant strains of P. aeruginosa were determined. In vitro time-kill studies were performed using free and liposomal gentamicin at 1, 2 or 4 times the MICs. The average liposomal size was 426.25 +/- 13.56 nm, with a gentamicin encapsulation efficiency of 4.51 +/- 0.54%. The MICs for liposomal gentamicin were significantly lower than those of corresponding free gentamicin. In addition, the time-kill values for liposomal gentamicin were either equivalent to or better than those of the free antibiotic. In conclusion, our liposomal gentamicin formulation is a more potent antipseudomonal drug with an improved killing time and prolonged antimicrobial activity. PMID:16472992

  1. A human tRNA methyltransferase 9-like protein prevents tumour growth by regulating LIN9 and HIF1-α.

    Science.gov (United States)

    Begley, Ulrike; Sosa, Maria Soledad; Avivar-Valderas, Alvaro; Patil, Ashish; Endres, Lauren; Estrada, Yeriel; Chan, Clement T Y; Su, Dan; Dedon, Peter C; Aguirre-Ghiso, Julio A; Begley, Thomas

    2013-03-01

    Emerging evidence points to aberrant regulation of translation as a driver of cell transformation in cancer. Given the direct control of translation by tRNA modifications, tRNA modifying enzymes may function as regulators of cancer progression. Here, we show that a tRNA methyltransferase 9-like (hTRM9L/KIAA1456) mRNA is down-regulated in breast, bladder, colorectal, cervix and testicular carcinomas. In the aggressive SW620 and HCT116 colon carcinoma cell lines, hTRM9L is silenced and its re-expression and methyltransferase activity dramatically suppressed tumour growth in vivo. This growth inhibition was linked to decreased proliferation, senescence-like G0/G1-arrest and up-regulation of the RB interacting protein LIN9. Additionally, SW620 cells re-expressing hTRM9L did not respond to hypoxia via HIF1-α-dependent induction of GLUT1. Importantly, hTRM9L-negative tumours were highly sensitive to aminoglycoside antibiotics and this was associated with altered tRNA modification levels compared to antibiotic resistant hTRM9L-expressing SW620 cells. Our study links hTRM9L and tRNA modifications to inhibition of tumour growth via LIN9 and HIF1-α-dependent mechanisms. It also suggests that aminoglycoside antibiotics may be useful to treat hTRM9L-deficient tumours. PMID:23381944

  2. Current epidemiology and growing resistance of gram-negative pathogens.

    Science.gov (United States)

    Livermore, David M

    2012-06-01

    In the 1980s, gram-negative pathogens appeared to have been beaten by oxyimino-cephalosporins, carbapenems, and fluoroquinolones. Yet these pathogens have fought back, aided by their membrane organization, which promotes the exclusion and efflux of antibiotics, and by a remarkable propensity to recruit, transfer, and modify the expression of resistance genes, including those for extended-spectrum β-lactamases (ESBLs), carbapenemases, aminoglycoside-blocking 16S rRNA methylases, and even a quinolone-modifying variant of an aminoglycoside-modifying enzyme. Gram-negative isolates--both fermenters and non-fermenters--susceptible only to colistin and, more variably, fosfomycin and tigecycline, are encountered with increasing frequency, including in Korea. Some ESBLs and carbapenemases have become associated with strains that have great epidemic potential, spreading across countries and continents; examples include Escherichia coli sequence type (ST)131 with CTX-M-15 ESBL and Klebsiella pneumoniae ST258 with KPC carbapenemases. Both of these high-risk lineages have reached Korea. In other cases, notably New Delhi Metallo carbapenemase, the relevant gene is carried by promiscuous plasmids that readily transfer among strains and species. Unless antibiotic stewardship is reinforced, microbiological diagnosis accelerated, and antibiotic development reinvigorated, there is a real prospect that the antibiotic revolution of the 20th century will crumble. PMID:22707882

  3. Combination Therapy of Sophoraflavanone B against MRSA: In Vitro Synergy Testing.

    Science.gov (United States)

    Mun, Su-Hyun; Kang, Ok-Hwa; Joung, Dae-Ki; Kim, Sung-Bae; Seo, Yun-Soo; Choi, Jang-Gi; Lee, Young-Seob; Cha, Seon-Woo; Ahn, Young-Sup; Han, Sin-Hee; Kwon, Dong-Yeul

    2013-01-01

    Sophoraflavanone B (SPF-B), a known prenylated flavonoid, was isolated from the roots of Desmodium caudatum. The aim of this study was to determine the antimicrobial synergism of SPF-B combined with antibiotics against methicillin-resistant Staphylococcus aureus (MRSA). MRSA, a multidrug-resistant pathogen, causes both hospital- and community-acquired infections worldwide. The antimicrobial activity of SPF-B was assessed by the broth microdilution method, checkerboard dilution test, and time-kill curve assay. The MIC of SPF-B for 7 strains of S. aureus ranges from 15.6 to 31.25  μ g/mL determined. In the checkerboard method, the combinations of SPF-B with antibiotics had a synergistic effect; SPF-B markedly reduced the MICs of the β -lactam antibiotics: ampicillin (AMP) and oxacillin (OXI); aminoglycosides gentamicin (GET); quinolones ciprofloxacin (CIP) and norfloxacin (NOR) against MRSA. The time-kill curves assay showed that a combined SPF-B and selected antibiotics treatment reduced the bacterial counts below the lowest detectable limit after 24 h. These data suggest that the antibacterial activity of SPF-B against MRSA can be effectively increased through its combination with three groups of antibiotics ( β -lactams, aminoglycosides, and quinolones). Our research can be a valuable and significant source for the development of a new antibacterial drug with low MRSA resistance. PMID:24319486

  4. Antibiotic resistance in Escherichia coli strains isolated from Antarctic bird feces, water from inside a wastewater treatment plant, and seawater samples collected in the Antarctic Treaty area

    Science.gov (United States)

    Rabbia, Virginia; Bello-Toledo, Helia; Jiménez, Sebastián; Quezada, Mario; Domínguez, Mariana; Vergara, Luis; Gómez-Fuentes, Claudio; Calisto-Ulloa, Nancy; González-Acuña, Daniel; López, Juana; González-Rocha, Gerardo

    2016-06-01

    Antibiotic resistance is a problem of global concern and is frequently associated with human activity. Studying antibiotic resistance in bacteria isolated from pristine environments, such as Antarctica, extends our understanding of these fragile ecosystems. Escherichia coli strains, important fecal indicator bacteria, were isolated on the Fildes Peninsula (which has the strongest human influence in Antarctica), from seawater, bird droppings, and water samples from inside a local wastewater treatment plant. The strains were subjected to molecular typing with pulsed-field gel electrophoresis to determine their genetic relationships, and tested for antibiotic susceptibility with disk diffusion tests for several antibiotic families: β-lactams, quinolones, aminoglycosides, tetracyclines, phenicols, and trimethoprim-sulfonamide. The highest E. coli count in seawater samples was 2400 cfu/100 mL. Only strains isolated from seawater and the wastewater treatment plant showed any genetic relatedness between groups. Strains of both these groups were resistant to β-lactams, aminoglycosides, tetracycline, and trimethoprim-sulfonamide.In contrast, strains from bird feces were susceptible to all the antibiotics tested. We conclude that naturally occurring antibiotic resistance in E. coli strains isolated from Antarctic bird feces is rare and the bacterial antibiotic resistance found in seawater is probably associated with discharged treated wastewater originating from Fildes Peninsula treatment plants.

  5. Macrophage adaptation leads to parallel evolution of genetically diverse Escherichia coli small-colony variants with increased fitness in vivo and antibiotic collateral sensitivity.

    Science.gov (United States)

    Ramiro, Ricardo S; Costa, Henrique; Gordo, Isabel

    2016-09-01

    Small-colony variants (SCVs) are commonly observed in evolution experiments and clinical isolates, being associated with antibiotic resistance and persistent infections. We recently observed the repeated emergence of Escherichia coli SCVs during adaptation to the interaction with macrophages. To identify the genetic targets underlying the emergence of this clinically relevant morphotype, we performed whole-genome sequencing of independently evolved SCV clones. We uncovered novel mutational targets, not previously associated with SCVs (e.g. cydA, pepP) and observed widespread functional parallelism. All SCV clones had mutations in genes related to the electron-transport chain. As SCVs emerged during adaptation to macrophages, and often show increased antibiotic resistance, we measured SCV fitness inside macrophages and measured their antibiotic resistance profiles. SCVs had a fitness advantage inside macrophages and showed increased aminoglycoside resistance in vitro, but had collateral sensitivity to other antibiotics (e.g. tetracycline). Importantly, we observed similar results in vivo. SCVs had a fitness advantage upon colonization of the mouse gut, which could be tuned by antibiotic treatment: kanamycin (aminoglycoside) increased SCV fitness, but tetracycline strongly reduced it. Our results highlight the power of using experimental evolution as the basis for identifying the causes and consequences of adaptation during host-microbe interactions. PMID:27606007

  6. Antibiotic allergy in cystic fibrosis.

    Science.gov (United States)

    Parmar, J S; Nasser, S

    2005-06-01

    Allergic reactions to antibiotics are more common in cystic fibrosis (CF) than in the general population. This in part is due to the improving survival in adults with CF and the increased use of high dose intravenous antibiotics. While some are immediate anaphylaxis type (IgE mediated) reactions, the majority are late onset and may have non-specific features such as rash and fever. Piperacillin has consistently been found to have the highest rate of reported reactions (30-50%). There is a low risk of cross reactions between penicillins and other non-beta-lactam classes of antibiotics in penicillin skin prick positive patients. Carbapenems should only be used with extreme caution in patients with positive skin prick tests to penicillin. However, aztreonam can be used safely in patients who are penicillin allergic with positive skin prick reactions. The aminoglycosides are a relatively uncommon cause of allergic reactions, but patients who react to one member of the family may cross react with other aminoglycosides. Desensitisation relies on the incremental introduction of small quantities of the allergen and has been used for penicillins, ceftazidime, tobramycin and ciprofloxacin and must be repeated before each course. Personalized cards should be regularly updated for patients who develop allergic reactions. Written instructions on the emergency treatment of allergic reactions should be provided to patients self-administering intravenous antibiotics at home. Further research is required to identify risk factors and predictors for antibiotic allergy. PMID:15923254

  7. Heavy metals in liquid pig manure in light of bacterial antimicrobial resistance

    Energy Technology Data Exchange (ETDEWEB)

    Hoelzel, Christina S., E-mail: Christina.Hoelzel@wzw.tum.de [Chair of Animal Hygiene, Technische Universitaet Muenchen, Weihenstephaner Berg 3, 85354 Freising (Germany); Mueller, Christa [Institute for Agroecology, Organic Farming and Soil Protection, Bavarian State Research Center for Agriculture (LfL), Lange Point 12, 85354 Freising (Germany); Harms, Katrin S. [Chair of Animal Hygiene, Technische Universitaet Muenchen, Weihenstephaner Berg 3, 85354 Freising (Germany); Mikolajewski, Sabine [Department for Quality Assurance and Analytics, Bavarian State Research Center for Agriculture (LfL), Lange Point 4, 85354 Freising (Germany); Schaefer, Stefanie; Schwaiger, Karin; Bauer, Johann [Chair of Animal Hygiene, Technische Universitaet Muenchen, Weihenstephaner Berg 3, 85354 Freising (Germany)

    2012-02-15

    Heavy metals are regularly found in liquid pig manure, and might interact with bacterial antimicrobial resistance. Concentrations of heavy metals were determined by atomic spectroscopic methods in 305 pig manure samples and were connected to the phenotypic resistance of Escherichia coli (n=613) against 29 antimicrobial drugs. Concentrations of heavy metals (/kg dry matter) were 0.08-5.30 mg cadmium, 1.1-32.0 mg chrome, 22.4-3387.6 mg copper, <2.0-26.7 mg lead, <0.01-0.11 mg mercury, 3.1-97.3 mg nickel and 93.0-8239.0 mg zinc. Associated with the detection of copper and zinc, resistance rates against {beta}-lactams were significantly elevated. By contrast, the presence of mercury was significantly associated with low antimicrobial resistance rates of Escherichia coli against {beta}-lactams, aminoglycosides and other antibiotics. Effects of subinhibitory concentrations of mercury on bacterial resistance against penicillins, cephalosporins, aminoglycosides and doxycycline were also demonstrated in a laboratory trial. Antimicrobial resistance in the porcine microflora might be increased by copper and zinc. By contrast, the occurrence of mercury in the environment might, due to co-toxicity, act counter-selective against antimicrobial resistant strains.

  8. Infections caused by Stenotrophomonas maltophilia in recipients of hematopoietic stem cell transplantation

    Directory of Open Access Journals (Sweden)

    KhalidAhmedAl-Anazi

    2014-08-01

    Full Text Available Stenotrophomonas maltophilia (S. maltophilia is a globally emerging Gram-negative bacillus that is widely spread in environment and hospital equipment. Recently, the incidence of infections caused by this organism has increased, particularly in patients with hematological malignancy and in recipients of hematopoietic stem cell transplantation having neutropenia, mucositis, diarrhea, central venous catheters or graft versus host disease and receiving intensive cytotoxic chemotherapy, immunosuppressive therapy or broad-spectrum antibiotics. The spectrum of infections in hematopoietic stem cell transplantation recipients includes: pneumonia, urinary tract and surgical site infection, peritonitis, bacteremia, septic shock and infection of indwelling medical devices. The organism exhibits intrinsic resistance to many classes of antibiotics including carbapenems, aminoglycosides, most of the third generation cephalosporins and other β-lactams. Despite the increasingly reported drug resistance, trimethoprim-sulfamethoxazole is still the drug of choice However, the organism is still susceptible to: ticarcillin-clavulanic acid, tigecycline, fluoroquinolones, polymyxin-B and rifampicin. Genetic factors play a significant role not only in evolution of drug resistance but also in virulence of the organism. The outcome of patients having S. maltophilia infections can be improved by: using various combinations of novel therapeutic agents and aerosolized aminoglycosides or colistin, prompt administration of in-vitro active antibiotics, removal of possible sources of infection such as infected indwelling intravacular catheters and application of strict infection control measures.

  9. Urgent Need to Antibiotic Pharmacokinetic Services for Iranian Health Care Centers

    Directory of Open Access Journals (Sweden)

    Alireza Hayatshahi

    2013-02-01

    Full Text Available Considering the emergence of both Gram negative and Gram positive resistant bacterial strains in the recent years, makes it more prominent to utilize the existed antibiotics in an appropriate and justified way in the treatment of drug resistant infections. Many of the agents currently used to treat bacterial, viral and fungal infections do not need to be pharmacokinetically monitored; it means we do not require their serum levels in order to adjust the dose in a routine manner. Examples of these antibiotics are penicillins, cephalosporins, macrolides, tetracyclines, fluoroquinolones, etc. Of course these agents need dose adjustment based on renal and hepatic functions. On the other hand there are antibiotics which need to be monitored through their serum levels because of three main following reasons: 1-      To avoid overdosing patient and reduce the incidence of toxicities. 2-      To avoid underdosing patient, this may lead to the emergence of resistant strains and treatment failure. 3-      To optimize the dose of antibiotic to achieve the bactericidal or bacteriostatic effects needed to suppress the infective agent. At this point, we are using vancomycin as a broad spectrum Gram positive agent and aminoglycosides both for the synergism for Gram positive coverage and also for treatment of Gram negative infection in combination with other agents. According to the guidelines published by the accredited organizations like Infectious Diseases Society of America (IDSA and American Society of Healthcare Pharmacists (ASHP, it is crucially important to perform therapeutic drug monitoring (TDM for both vancomycin and aminoglycosides based on their serum levels for all patients on these agents. In the other word, it is a wrong antibiotic therapy without monitoring the levels. Almost in all medical centers nationwide including teaching hospitals the clinicians prescribe vancomycin very often and aminoglycosides like gentamicin and

  10. Comparative EPR Examination of Gentamicin, Kanamycin and Netilmicin Effects on Free Radicals in DOPA-Melan

    International Nuclear Information System (INIS)

    Free radical properties of DOPA-melanin and its complexes with gentamicin, kanamycin and netilmicin were studied by the use of electron paramagnetic resonance spectroscopy at Xband (9.3 GHz). Melanins demonstrate stable paramagnetism and ability to drugs binding. Interactions of melanins with aminoglycoside antibiotics are not well known so far. o-Semiquinone free radicals formed in melanin biopolymers may be responsible for toxic effects appearing during antibioticotherapy. In this work we compare changes in paramagnetic centers systems of DOPA-melanin - model eumelanin caused by binding of typical aminoglycoside antibiotics. DOPA-melanin was chosen for measurements, because it mainly exists in living organism. The EPR results for the individual drugs were presented in our earlier works. EPR measurements were performed by the use of EPR spectrometer with modulation of magnetic field 100 kHz produced by RADIOPA-Poznan. Microwave frequency was recorded. The first derivative EPR spectra were recorded with low microwave power 0.7 MW at room temperature. Free radical concentration, g-factor, and linewidths were determined. Ultramarine was used as a reference of concentration of paramagnetic centers. A ruby crystal permanently placed in the spectrometer cavity was the secondary reference. Area under the absorption curve was obtained by double integration of its first derivative. g-Factor was calculated from the resonance condition. The influence of microwave power in the range of 0.7-70 MW on EPR lines of DOPAmelanin and its complexes with the analysed antibiotics was tested. Changes of amplitudes and linewidths with increasing of microwave power were obtained. o-Semiquinone free radicals exist in all the studied melanin complexes. It was confirmed that aminoglycoside antibiotics generate additional o-semiquinone free radicals in melanin polymer. The relatively low amount of free radicals appears in melanin after complexing with netilmicin - an antibiotic which

  11. Allele-specific PCR for detecting the deafness-associated mitochondrial 12S rRNA mutations.

    Science.gov (United States)

    Ding, Yu; Xia, Bo-Hou; Liu, Qi; Li, Mei-Ya; Huang, Shui-Xian; Zhuo, Guang-Chao

    2016-10-10

    Mutations in mitochondrial 12S rRNA (MT-RNR1) are the important causes of sensorineural hearing loss. Of these mutations, the homoplasmic m.1555A>G or m.1494C>T mutation in the highly conserved A-site of MT-RNR1 gene has been found to be associated with both aminoglycoside-induced and non-syndromic hearing loss in many families worldwide. Since the m.1555A>G and m.1494C>T mutations are sensitive to ototoxic drugs, therefore, screening for the presence of these mutations is important for early diagnosis and prevention of deafness. For this purpose, we recently developed a novel allele-specific PCR (AS-PCR) which is able to simultaneously detect these mutations. To assess its accuracy, in this study, we employed this method to screen the frequency of m.1555A>G and m.1494C>T mutations in 200 deafness patients and 120 healthy subjects. Consequently, four m.1555A>G and four m.1494C>T mutations were identified; among these, only one patient with the m.1494C>T mutation had an obvious family history of hearing loss. Strikingly, clinical evaluation showed that this family exhibited a high penetrance of hearing loss. In particular, the penetrances of hearing loss were 80% with the aminoglycoside included and 20% when excluded. PCR-Sanger sequencing of the mitochondrial genomes confirmed the presence of the m.1494C>T mutation and identified a set of polymorphisms belonging to mitochondrial haplogroup A. However, the lack of functional variants in mitochondrial and nuclear modified genes (GJB2 and TRMU) in this family indicated that mitochondrial haplogroup and nuclear genes may not play important roles in the phenotypic expression of the m.1494C>T mutation. Thus, other modification factors, such as environmental factor, aminoglycosides or epigenetic modification may have contributed to the high penetrance of hearing loss in this family. Taken together, our data showed that this assay is an effective approach that could be used for detection the deafness-associated MT-RNR1

  12. Prevalence of 16S rRNA methylase, modifying enzyme, and extended-spectrum beta-lactamase genes among Acinetobacter baumannii isolates.

    Science.gov (United States)

    Liu, Zhenru; Ling, Baodong; Zhou, Liming

    2015-08-01

    Multidrug-resistant Acinetobacter baumannii has become a worldwide problem, and methylation of 16S rRNA has recently emerged as a new mechanism of resistance to aminoglycosides, which is mediated by a newly recognized group of 16S rRNA methylases. 16S rRNA methylase confers a high-level resistance to all 4,6-substituted deoxystreptamine aminoglycosides that are currently used in clinical practice. Some of the A. baumannii isolates have been found to coproduce extended-spectrum beta-lactamases (ESBLs), contributing to their multidrug resistance. The aim of this study was to detect the determinants of the 16S rRNA methylase genes armA, rmtA, rmtB, rmtC, rmtD, rmtE, and npmA, the modifying enzyme genes aac(6')-Ib, ant(3″)-Ia, aph(3')-I, and the extended-spectrum beta-lactamase genes bla(TEM), bla(SHV), and bla(CTX-M-3) among A. baumannii isolates in northeastern Sichuan, China. Minimum inhibitory concentrations (MICs) of 21 different antimicrobial agents against the A. baumannii isolates were determined. The clinical isolates showed a high level of resistance (MIC≧256 μg/ml) to aminoglycosides, which ranged from 50·1 to 83·8%. The resistances to meropenem and imipenem, two of the beta-lactam antibiotics and the most active antibiotics against A. baumannii, were 9·1 and 8·2%, respectively. Among 60 amikacin-resistant isolates, only the 16S rRNA methylase gene armA was found to be prevalent (66·7%), but the other 16S rRNA methylase genes rmtA, rmtB, rmtC, rmtD, rmtE, and npmA were not detected. The prevalences of the modifying enzyme genes aac (6')-Ib, ant (3″)-Ia, and aph (3')-I were 51·7, 81·7, and 58·3%, respectively, which are different from a previous study in which the occurrences of these genes were 3, 64, and 72%, respectively. Among the 40 isolates that were armA-positive, the prevalences of bla(TEM), bla(SHV), and bla(CTX-M-3) genes were detected for the first time in China, and their occurrences were 45, 65, and 52·5%, respectively. In all, A

  13. Whole genome sequencing-based characterization of extensively drug resistant (XDR) strains of Mycobacterium tuberculosis from Pakistan

    KAUST Repository

    Hasan, Zahra

    2015-03-01

    Objectives: The global increase in drug resistance in Mycobacterium tuberculosis (MTB) strains increases the focus on improved molecular diagnostics for MTB. Extensively drug-resistant (XDR) - TB is caused by MTB strains resistant to rifampicin, isoniazid, fluoroquinolone and aminoglycoside antibiotics. Resistance to anti-tuberculous drugs has been associated with single nucleotide polymorphisms (SNPs), in particular MTB genes. However, there is regional variation between MTB lineages and the SNPs associated with resistance. Therefore, there is a need to identify common resistance conferring SNPs so that effective molecular-based diagnostic tests for MTB can be developed. This study investigated used whole genome sequencing (WGS) to characterize 37 XDR MTB isolates from Pakistan and investigated SNPs related to drug resistance. Methods: XDR-TB strains were selected. DNA was extracted from MTB strains, and samples underwent WGS with 76-base-paired end fragment sizes using Illumina paired end HiSeq2000 technology. Raw sequence data were mapped uniquely to H37Rv reference genome. The mappings allowed SNPs and small indels to be called using SAMtools/BCFtools. Results: This study found that in all XDR strains, rifampicin resistance was attributable to SNPs in the rpoB RDR region. Isoniazid resistance-associated mutations were primarily related to katG codon 315 followed by inhA S94A. Fluoroquinolone resistance was attributable to gyrA 91-94 codons in most strains, while one did not have SNPs in either gyrA or gyrB. Aminoglycoside resistance was mostly associated with SNPs in rrs, except in 6 strains. Ethambutol resistant strains had embB codon 306 mutations, but many strains did not have this present. The SNPs were compared with those present in commercial assays such as LiPA Hain MDRTBsl, and the sensitivity of the assays for these strains was evaluated. Conclusions: If common drug resistance associated with SNPs evaluated the concordance between phenotypic and

  14. Hypomagnesaemia in paediatric population in an intensive care unit.

    Directory of Open Access Journals (Sweden)

    Deshmukh C

    2000-07-01

    Full Text Available AIMS: To determine incidence and risk factors for hypomagnesaemia in children admitted in Paediatric Intensive Care Unit, (PICU. SUBJECTS AND METHODS: Prospective study was carried out on 80 children admitted in PICU. The patients were clinically assessed for nutritional status, neurological status on Glasgow coma scale, congestive cardiac failure, etc. and relevant biochemical parameters including serum and red cell magnesium levels were done. 25 patients of the same age group admitted in general ward who were not in critical state were included as a control group. RESULTS: 70% of PICU patients had hypomagnesaemia, which was more common in patients on aminoglycosides and diuretics. CONCLUSION: In view of complications of magnesium depletion and benign nature of appropriate magnesium therapy critically ill children should have their magnesium level monitored.

  15. Overexpression of the mitochondrial methyltransferase TFB1M in the mouse does not impact mitoribosomal methylation status or hearing

    DEFF Research Database (Denmark)

    Lee, Seungmin; Rose, Simon; Metodiev, Metodi D;

    2015-01-01

    Mitochondrial dysfunction is a well-established cause of sensorineural deafness, but the pathophysiological events are poorly understood. Non-syndromic deafness and predisposition to aminoglycoside-induced deafness can be caused by specific mutations in the 12S rRNA gene of mtDNA and are thus...... 'hypermethylation' of two conserved adenosines of 12S rRNA in the mitoribosome is of key pathophysiological importance in sensorineural deafness. In support for this concept, it was reported that overexpression of the essential mitochondrial methyltransferase TFB1M in the mouse was sufficient to induce...... mitoribosomal hypermethylation and deafness. At variance with this model, we show here that 12S rRNA is near fully methylated in vivo in the mouse and thus cannot be further methylated to any significant extent. Furthermore, bacterial artificial chromosome transgenic mice overexpressing TFB1M have no increase...

  16. Osteomyelitis of the base of the skull

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, J.R.; Grobman, L.; Quencer, R.; Serafini, A.

    1986-03-01

    Infection in the marrow of the temporal, occipital, and sphenoid bones is an uncommon, but increasing occurrence. It is usually secondary to infections beginning in the external auditory canal and is caused almost uniformly by the gram negative Pseudomonas aeruginosa bacteria. Technetium and gallium scintigraphy help in the early detection of such infections while CT scans demonstrate dissolution of bone in well-developed cases. Headache is the predominant symptom. Dysphagia, hoarseness, and aspiration herald the inevitable march of cranial nerves. We have diagnosed and treated 17 cases of osteomyelitis of the skull base. Although the total mortality rate is 53%, it is now a curable disease. Six of our last 8 patients remain alive, although 1 is still under treatment. Treatment is medical and requires the long-term concomitant intravenous administration of an aminoglycoside and a broad spectrum semisynthetic penicillin effective against the causative organism.

  17. Antibiotic usage in 2013 on a dairy CAFO in NY State, USA

    Directory of Open Access Journals (Sweden)

    Marie Doane

    2014-05-01

    Full Text Available Antimicrobial resistance is threatening humans and animals worldwide. Biosecurity and 1-year usage of antibiotics on a dairy concentrated animal feeding operation (CAFO in NY State, USA, were mapped: how much antibiotics were used, for what purpose, and whether any decrease could be warranted. Approximately 493 kg antibiotics was used, of which 376 kg was ionophores (monensin and lasalocides, 79 kg penicillin, 16.5 kg lincosamides, 8.0 kg aminoglycosides, 7.7 kg sulfamides, 3.4 kg cephalosporin, 2 kg macrolides, 0.7 kg amphenicols, and 0.1 kg fluoroquinolones. Usage reduction by 84% was realistic without compromising the animal welfare. Further reduction could be possible by improving the biosecurity and by utilizing antibiotic sensitivity testing.

  18. Antibiotic resistance in lactic acid bacteria and Micrococcaceae/Staphylococcaceae isolates from artisanal raw milk cheeses, and potential implications on cheese making.

    Science.gov (United States)

    Rodríguez-Alonso, P; Fernández-Otero, C; Centeno, J A; Garabal, J I

    2009-08-01

    Antibiotic susceptibility against 19 antimicrobial agents was evaluated in isolates of the genera Lactococcus (46 isolates), Leuconostoc (22), Lactobacillus (19), Staphylococcus (8), Enterococcus (7), and Microccoccus/Kocuria (5) obtained from the predominant microflora of nonrecent and recent types of artisanal raw cow's milk cheeses. Beta-lactams showed broad activity against all genera, although leuconostocs and lactobacilli were highly resistant to oxacillin (80% to 95.5%). Resistance to aminoglycosides was frequent for lactococci and enterococci (particularly for streptomycin), whereas lower rates of resistance were detected for lactobacilli and leuconostocs. Technologically interesting traits for the food industry were distributed among isolates that showed different degrees of resistance to common antibiotics. However, isolates showing resistance to less than 2 antibiotics were mainly those with properties of greatest technological interest (acidifying activity, proteolytic/lipolytic activities, or diacetyl production). PMID:19723213

  19. Molecular therapies for inherited epidermolysis bullosa.

    Science.gov (United States)

    Has, Cristina

    2016-08-01

    Inherited epidermolysis bullosa (EB) comprises rare genetic disorders characterized by formation of blisters and erosions of skin and mucous membranes after minor mechanical trauma. The molecular basis and the pathomechanisms of the main EB types have been largely deciphered in the past decades. The burden of the disease is high and quality of life strongly affected. The treatment is still symptomatic aiming to support wound healing and resolve complications. Numerous experimental therapeutic approaches for EB have been explored in the last years, most of them dedicated to dystrophic EB. Although gene and cell therapies have been already applied in patients, molecular therapies including gene editing and repurposing of small molecules are currently very attractive. Recent data on the effect of small molecules, like aminoglycosides and angiotensin receptor blockers in preclinical models for dystrophic EB are encouraging. The efficacy in patients remains to be proven in clinical trials. Therapeutic efficacy, as well as unexpected outcomes must be carefully monitored. PMID:27149615

  20. Antibiotic susceptibility profile of Aeromonas spp. isolates from food in Abu Dhabi, United Arab Emirates.

    Science.gov (United States)

    Awan, Mohammad Bashir; Maqbool, Ahmed; Bari, Abdul; Krovacek, Karel

    2009-01-01

    A total of 57 Aeromonas isolates from food samples such as fresh and frozen chicken, game birds, pasteurized milk, baby food, bakery products, fruit and vegetables, fish, and water from Abu Dahbi, UAE were investigated for antibiotic susceptibility profile. Most strains were resistant to penicillins (ticarcillin, mezlocillin, oxacillin, piperacillin), sulfamethoxazole, trimethoprim and macrolides (erythromycin, vancomycin, clindamycin) but sensitive to tetracycline, chloramphenicol, nitrofurantoin, aminoglycosides (amikacin, gentamicin, tobramycin), cephalosporins (cefuroxime, ceftrioxone, cefazolin, cephalexin, cephalothin, cefoxitin, cefotaxime), quinolone (ciprofloxacin), colistin sulphate and SXT (trimethoprim-sulfamethoxazole). On the other hand, many antibiotics showed excellent inhibitory activity (>75% strains were sensitive to them) against all the strains tested. These include cefuroxime, ceftrioxone, ciprofloxacin, colistin, amikacin, gentamicin, tetracycline, chloramphenicol, nitrofurantoin, cefotaxime and tobramycin. In conclusion, the results show a detailed pattern of sensitivity of the various Aeromonas spp. isolates to a variety of antibiotics and provide useful information in the context of selective isolation and phenotypic identification of the aeromonads from food. PMID:19382665

  1. Industrial disinfectants do not select for resistance in Listeria monocytogenes following long term exposure

    DEFF Research Database (Denmark)

    Kastbjerg, Vicky Gaedt; Gram, Lone

    2012-01-01

    Listeria monocytogenes is a food-borne pathogen that can persist for years in food processing plants. It has been hypothesized that this could be due to the development of tolerance or resistance to the disinfectants used. The purpose of the present study was to determine whether biocide resistance...... inhibitory concentration (MIC) to the disinfectants, whereas exposure to Triquart SUPER (quaternary ammonium compounds) caused a two- to four-fold increase in MIC. Exposure to gentamicin, which was used as a positive control, caused an 8 to 256-fold increase in MIC for several aminoglycosides. Despite the...... low level of tolerance, the populations adapted to Triquart SUPER were still sensitive to killing with this disinfectant at 0.0125%, which is much lower than in-use concentrations (1–5%). Our data are in agreement with the fact that finding strains with high acquired resistance to disinfectants is...

  2. Analysis of the Kanamycin in Raw Milk Using the Suspension Array

    Directory of Open Access Journals (Sweden)

    Yanfei Wang

    2013-01-01

    Full Text Available With the monoclonal antibody against kanamycin being prepared successfully, a bead-based indirect competitive fluorescent immunoassay was developed to detect kanamycin in milk. The fact that there was no significant cross-reaction with other aminoglycoside antibiotics implied that the monoclonal antibody was highly specific for kanamycin. The limit of detection (LOD and the 50% inhibition concentration (IC50 in raw milk were 3.2 ng/mL and 52.5 ng/mL, respectively. Using the method developed in this study, the kanamycin concentrations were monitored in raw milk after the intramuscular administration of kanamycin in sick cows. Compared to the conventional enzyme-linked immunosorbent assay (ELISA, the method using the suspension array system was more sensitive. The results obtained in the present study showed a good correlation with that of the ELISA.

  3. Design of Ionizable Lipids To Overcome the Limiting Step of Endosomal Escape: Application in the Intracellular Delivery of mRNA, DNA, and siRNA.

    Science.gov (United States)

    Habrant, Damien; Peuziat, Pauline; Colombani, Thibault; Dallet, Laurence; Gehin, Johan; Goudeau, Emilie; Evrard, Bérangère; Lambert, Olivier; Haudebourg, Thomas; Pitard, Bruno

    2016-04-14

    The intracellular delivery of nucleic acid molecules is a complex process involving several distinct steps; among these the endosomal escape appeared to be of particular importance for an efficient protein production (or inhibition) into host cells. In the present study, a new series of ionizable vectors, derived from naturally occurring aminoglycoside tobramycin, was prepared using improved synthetic procedures that allow structural variations on the linker and hydrophobic domain levels. Complexes formed between the new ionizable lipids and mRNA, DNA, or siRNA were characterized by cryo-TEM experiments and their transfection potency was evaluated using different cell types. We demonstrated that lead molecule 30, bearing a biodegradable diester linker, formed small complexes with nucleic acids and provided very high transfection efficiency with all nucleic acids and cell types tested. The obtained results suggested that the improved and "universal" delivery properties of 30 resulted from an optimized endosomal escape, through the lipid-mixing mechanism. PMID:26943260

  4. Inhibition of mammalian mitochondrial protein synthesis by oxazolidinones.

    Science.gov (United States)

    McKee, E E; Ferguson, M; Bentley, A T; Marks, T A

    2006-06-01

    The effects of a variety of oxazolidinones, with different antibacterial potencies, including linezolid, on mitochondrial protein synthesis were determined in intact mitochondria isolated from rat heart and liver and rabbit heart and bone marrow. The results demonstrate that a general feature of the oxazolidinone class of antibiotics is the inhibition of mammalian mitochondrial protein synthesis. Inhibition was similar in mitochondria from all tissues studied. Further, oxazolidinones that were very potent as antibiotics were uniformly potent in inhibiting mitochondrial protein synthesis. These results were compared to the inhibitory profiles of other antibiotics that function by inhibiting bacterial protein synthesis. Of these, chloramphenicol and tetracycline were significant inhibitors of mammalian mitochondrial protein synthesis while the macrolides, lincosamides, and aminoglycosides were not. Development of future antibiotics from the oxazolidinone class will have to evaluate potential mitochondrial toxicity. PMID:16723564

  5. Osteomyelitis of the base of the skull

    International Nuclear Information System (INIS)

    Infection in the marrow of the temporal, occipital, and sphenoid bones is an uncommon, but increasing occurrence. It is usually secondary to infections beginning in the external auditory canal and is caused almost uniformly by the gram negative Pseudomonas aeruginosa bacteria. Technetium and gallium scintigraphy help in the early detection of such infections while CT scans demonstrate dissolution of bone in well-developed cases. Headache is the predominant symptom. Dysphagia, hoarseness, and aspiration herald the inevitable march of cranial nerves. We have diagnosed and treated 17 cases of osteomyelitis of the skull base. Although the total mortality rate is 53%, it is now a curable disease. Six of our last 8 patients remain alive, although 1 is still under treatment. Treatment is medical and requires the long-term concomitant intravenous administration of an aminoglycoside and a broad spectrum semisynthetic penicillin effective against the causative organism

  6. Detection of Multi-drug Resistant Acinetobacter Lwoffii Isolated from Soil of Mink Farm.

    Science.gov (United States)

    Sun, Na; Wen, Yong Jun; Zhang, Shu Qin; Zhu, Hong Wei; Guo, Li; Wang, Feng Xue; Chen, Qiang; Ma, Hong Xia; Cheng, Shi Peng

    2016-07-01

    There were 4 Acinetobacter lwoffii obtained from soil samples. The antimicrobial susceptibility of the strains to 16 antimicrobial agents was investigated using K-B method. Three isolates showed the multi-drug resistance. The presence of resistance genes and integrons was determined using PCR. The aadA1, aac(3')-IIc, aph(3')-VII, aac(6')-Ib, sul2, cat2, floR, and tet(K) genes were detected, respectively. Three class 1 integrons were obtained. The arr-3-aacA4 and blaPSE-1 gene cassette, which cause resistance to aminoglycoside and beta-lactamase antibiotics. Our results reported the detection of multi-drug resistant and carried resistant genes Acinetobacter lwoffii from soil. The findings suggested that we should pay close attention to the prevalence of multi-drug resistant bacterial species of environment. PMID:27554122

  7. [Bacteriocidal activity of Streptomyces cultures].

    Science.gov (United States)

    Polishchuk, L V; Bambura, O I; Luk'ianchuk, V V

    2012-01-01

    Bacteriocidal activity of metabolites synthesized by 17 plasmid-containing cultures of Streptomyces has been studied. These cultures were isolated from soils of Ukraine with different anthropogenic contamination. The cultures, in their majority (85.3%), synthesized bioactive metabolites, which suppressed growth of microorganisms of different taxonomical groups, pathogenic for people, animals or plants. None of 17 Streptomyces cultures was able to suppress growth of yeasts or Escherichia coli. All 17 investigated cultures of Streptomyces were polyresistant to antibiotics, which were used in medicine and veterinary: makrolide, aminoglycoside, beta-lactam and other groups. Resistance of 8 cultures to the antibiotic thiostrepton, which was widely used in some branches of science, was found. PMID:23088099

  8. Interaction between the renal excretion rates of beta 2-microglobulin and tobramycin in man.

    Science.gov (United States)

    Vree, T B; Zweens, K; Huige, P J; Guelen, P J; Jongman-Nix, B

    1984-03-27

    The renal excretion rate of beta 2-microglobulin in man is 127 +/- 98 ng/min at alkaline urine pH (pH 7). Tobramycin, up to intravenous doses of 160 mg (2 mg/kg) does not increase the renal excretion rate of beta 2-microglobulin. Tobramycin must have less affinity than gentamicin for the tubular system for active reabsorption of amino groups containing organic compounds. Due to this reduced affinity tobramycin will be absorbed less by the proximal tubular cells, which may be one of the reasons for tobramycin being less toxic than gentamicin. beta 2-Microglobulin excretion can be used as a parameter for the relative binding affinity of aminoglycosides. PMID:6370509

  9. Comparative Study Between 99mTc-Kanamycin And 99mTc-Gentamicin As Diagnostic Agents For Bacterial Infection

    International Nuclear Information System (INIS)

    Kanamycin and gentamicin are aminoglycosides antibiotics indispensable in the therapy of acute infections. Labelling with Tc-99m depends on the ligand and reducing agent concentrations, pH and the reaction time. Radiochemical yield and stability were determined by paper and thin layer chromatography. Biodistribution studies of 99mTc-kanamycin and 99mTc-gentamicin were performed in rats. The localization of radioactivity of both complexes in infected sites induced by Staphylococcus aureus indicated the high binding affinity of these drugs. 99mTc-gentamicin has an effective bacterial action against gram positive bacteria S. aureus which confirms the efficacy of this complex as diagnostic agent for bacterial infections.

  10. Treatment of Staphylococcus aureus keratitis with 0.2% topical linezolid

    Directory of Open Access Journals (Sweden)

    Lincoln Lavado Landeo

    2015-09-01

    Full Text Available Objective: To report the use of 0.2% topical linezolid in the treatment of Staphylococcus aureus keratitis with successful results. Material and methods: All cases were viewed in Centro Vision, here they underwent a complete ophthalmic examination and were diagnosed with Staphylococcus aureus keratitis based on a microbiological study. In both cases we began with the gold standard therapy based on fortified topical drops of vancomycin and an aminoglycoside. Due to ineffective action and/or poor tolerance of vancomycin, we decided to use topical linezolid. Results: Two female patients with Staphylococcus aureus keratitis received ocular 0.2% topical linezolid every hour. In both cases we saw a marked clinical improvement and a good tolerance to this antibiotic. Conclusions: 0.2% Topical linezolid is an effective and well tolerated antibiotic when used in the treatment of Staphylococcus aureus keratitis. It is more comfortable and less toxic than topical vancomycin.

  11. Antibiotic and disinfectant susceptibility profiles of vancomycin-resistant Enterococcus faecium (VRE) isolated from community wastewater in Texas.

    Science.gov (United States)

    Beier, Ross C; Duke, Sara E; Ziprin, Richard L; Harvey, Roger B; Hume, Michael E; Poole, Toni L; Scott, H Morgan; Highfield, Linda D; Alali, Walid Q; Andrews, Kathleen; Anderson, Robin C; Nisbet, David J

    2008-03-01

    Vancomycin-resistant Enterococcus faecium (VRE) from human wastewater effluents in a nonclinical semiclosed agri-food system in Texas were characterized for susceptibility to antibiotics and disinfectants. The 50 VRE were resistant to eight fluoroquinolones and 10 of 17 antimicrobials typically active against Gram-positive organisms. The VRE were susceptible to quinupristin/dalfopristin and linezolid. Lack of the insertion element IS1251 correlated with VRE susceptibility to streptomycin and gentamicin at p or =2 ppm. Triclosan MICs for many of the VRE were well over expected product application levels. No association was observed between antibiotic resistance and disinfectant susceptibility in these VRE. Enterococci multiply-resistant to vancomycin and aminoglycosides were found in a non-hospital environment where one would not expect to find them. PMID:18193143

  12. Antimicrobial susceptibility of clinical isolates of Acinetobacter baumannii.

    Science.gov (United States)

    Shi, Z Y; Liu, P Y; Lau, Y; Lin, Y; Hu, B S; Shir J-M

    1996-02-01

    The in-vitro activity of 18 antimicrobial agents alone or in combination against 248 clinical isolates of Acinetobacter baumannii from Taiwan were tested by agar dilution. The MIC90S of ampicillin, amoxicillin, piperacillin, cefuroxime, cefotaxime, ceftriaxone, gentamicin, and amikacin were at least 128 mu g/ml. Ceftazidime, cefepime, sulbactam, clavulanic acid, and tazobactam presented moderate activity with MIC90S of 32, 16, 16, 32, and 32 mu g/ml, respectively. The increased activity of ampicillin/sulbactam, amoxicillin/clavulanic acid, and piperacillin/tazobactam was due to the intrinsic effect of sulbactam, clavulanic acid, and tazobactam, respectively. Imipenem, meropenem, and ciprofloxacin were the most active antimicrobial agents with MIC90S of 1, 1, and 0.5 mu g/ml, respectively. Nineteen isolates (7.7%) were resistant to all aminoglycosides and beta-lactam antibiotics, except carbapenems and ciprofloxacin. We are concerned about the multidrug resistance of A. baumannii in this study. PMID:9147913

  13. Enzymatic radioassay for gentamicin

    International Nuclear Information System (INIS)

    An enzymatic radiochemical assay procedure for measuring serum gentamicin by use of gentamicin 3-acetyltransferase and [acetyl-14C]acetyl-Coenzyme A is described and evaluated. The enzyme stoichiometrically and quantitatively transfers a radioactive label to the analyte during a 10-min incubation at 370C. The labeled gentamicin is then adsorbed onto phosphocellulose paper discs, which are washed to remove unreacted [acetyl-14C]acetyl-Coenzyme A and counted in a liquid scintillation counter for 1 min each. The assay detects gentamicin in concentrations as low as 0.2 mg/liter and gives a linear response to concentrations as high as 20 mg/liter. Sisomicin, a structural analog of gentamicin, is measured by the procedure, and tobramycin and netilmicin are slightly reactive. No other interferents were found among other aminoglycosides, other antibiotics, or substances endogenous to serum. Results by the new method are compared to those by radioimmunoassay and a microbiological method

  14. Paramagnetic Centers in DOPA-Melanin-Dihydrostreptomycin Complexes

    Science.gov (United States)

    Buszman, E.; Pilawa, B.; Zdybel, M.; Wrześniok, D.; Grzegorczyk, A.; Wilczok, T.

    2006-08-01

    DOPA-melanin-dihydrostreptomycin complexes with drug concentrations 1×10-4-1×10-2 M were examined by the use of electron paramagnetic resonance spectroscopy at X-band (9.3 GHz). Dihydrostreptomycin was chosen for studies, because this aminoglycoside antibiotic causes strong toxic effects in organism. It was stated that dihydrostreptomycin generates o-semiquinone free radicals with g=2.0038 in melanin. Free radicals formation increases with increase in the antibiotic concentration. Changes of EPR lines with microwave powers pointed out that slow spin-lattice relaxation processes exist in DOPA-melanin and in its complexes with dihydrostreptomycin. The measured EPR lines were homogeneously broadened.

  15. Isolated Streptococcus agalactiae tricuspid endocarditis in elderly patient without known predisposing factors: Case report and review of the literature.

    Science.gov (United States)

    Abid, Leila; Charfeddine, Salma; Kammoun, Samir

    2016-04-01

    Group B streptococcal (GBS) tricuspid infective endocarditis is a very rare clinical entity. It affects intravenous drug users, pregnant, postpartum women, and the elderly. We report the case of a 68-year-old patient without known predisposing factors who presented a GBS tricuspid endocarditis treated by penicillin and aminoglycosides with no response. The patient was operated with a good evolution. Our case is the 25th reported in the literature. GBS disease is increasing in the elderly and is mainly associated to comorbid conditions. Tricuspid infective endocarditis with Group B streptococcus predominantly presents as a persistent fever with respiratory symptoms due to pulmonary embolism. Therefore, it requires a medicosurgical treatment and close follow-up. PMID:27053903

  16. Multiple drug resistance of Aeromonas hydrophila isolates from Chicken samples collected from Mhow and Indore city of Madhyapradesh

    Directory of Open Access Journals (Sweden)

    Kaskhedikar

    2009-02-01

    Full Text Available Fourteen antibacterial agents belonging to 9 different groups of antibiotics viz. aminoglycosides, cephalosporins, nitrofurantoin, fluroquinolones, chloramphenicol, sulphonamides, tetracyclines, penicillin and polymixin were used for in vitro sensitivity testing of Aeromonas hydrophila isolated from fifteen samples of chicken collected from retail shops in Mhow city. The sensitivity (100% was attributed to ciprofloxacin, cefuroxime, ceftriaxone, cephotaxime, chloramphenicol, gentamycin, kanamycin, nitrofurantoin, nalidixic acid and ofloxacin followed by oxytetracycline (50%. All the isolates were resistant to ampicillin and colistin antibiotics. That means, none of the isolates were found to be sensitive for penicillin and polymixin group of antibiotics. Multiple drug resistance was also observed in all A. hydrophila isolates. Out of total isolates, 100% were resistant to two antimicrobial drugs and 50% to three drugs. [Vet. World 2009; 2(1.000: 31-32

  17. Long-Term Blocking of Calcium Channels in mdx Mice Results in Differential Effects on Heart and Skeletal Muscle

    DEFF Research Database (Denmark)

    Jørgensen, Louise Helskov; Blain, Alison; Greally, Elizabeth;

    2011-01-01

    The disease mechanisms underlying dystrophin-deficient muscular dystrophy are complex, involving not only muscle membrane fragility, but also dysregulated calcium homeostasis. Specifically, it has been proposed that calcium channels directly initiate a cascade of pathological events by allowing...... calcium ions to enter the cell. The objective of this study was to investigate the effect of chronically blocking calcium channels with the aminoglycoside antibiotic streptomycin from onset of disease in the mdx mouse model of Duchenne muscular dystrophy (DMD). Treatment in utero onwards delayed onset of...... older mice. However, streptomycin treatment did not show positive effects in diaphragm or heart muscle, and heart pathology was worsened. Thus, blocking calcium channels even before disease onset does not prevent dystrophy, making this an unlikely treatment for DMD. These findings highlight the...

  18. Multidrug-resistant tuberculosis in the United Kingdom and Lithuania.

    Science.gov (United States)

    Gonzalo, X; Hutchison, D C S; Drobniewski, F A; Pimkina, E; Davidaviciene, E

    2014-06-01

    Rates of resistance to first- and second-line drugs in multidrug-resistant tuberculosis (MDR-TB) cases in the United Kingdom were studied during 2010-2012. The highest rates for ethambutol, pyrazinamide and aminoglycosides occurred among patients originating in Eastern Europe, of whom 47% were Lithuanian. Rates of resistance to kanamycin were significantly lower (P < 0.0001) in the Lithuanian National TB Register than among Lithuanian patients resident in the United Kingdom (5% vs. 78%). In 2010, the majority of UK patients of Eastern European origin were located within the London region, whereas in 2011 the majority were located outside this region, a significant change (P = 0.01). PMID:24903935

  19. Nocardia transvalensis Disseminated Infection in an Immunocompromised Patient with Idiopathic Thrombocytopenic Purpura

    Science.gov (United States)

    García-Méndez, Jorge; Carrillo-Casas, Erika M.; Rangel-Cordero, Andrea; Leyva-Leyva, Margarita; Xicohtencatl-Cortes, Juan; Arenas, Roberto; Hernández-Castro, Rigoberto

    2016-01-01

    Nocardia transvalensis complex includes a wide range of microorganisms with specific antimicrobial resistance patterns. N. transvalensis is an unusual Nocardia species. However, it must be differentiated due to its natural resistance to aminoglycosides while other Nocardia species are susceptible. The present report describes a Nocardia species involved in an uncommon clinical case of a patient with idiopathic thrombocytopenic purpura and pulmonary nocardiosis. Microbiological and molecular techniques based on the sequencing of the 16S rRNA gene allowed diagnosis of Nocardia transvalensis sensu stricto. The successful treatment was based on trimethoprim-sulfamethoxazole and other drugs. We conclude that molecular identification of Nocardia species is a valuable technique to guide good treatment and prognosis and recommend its use for daily bases diagnosis. PMID:27313917

  20. Development of antibiotic resistance in Pseudomonas aeruginosa during two decades of antipseudomonal treatment at the Danish CF Center

    DEFF Research Database (Denmark)

    Ciofu, O; Giwercman, B; Pedersen, S S;

    1994-01-01

    At the Danish CF Center patients with chronic Pseudomonas aeruginosa lung infection were treated 3-4 times a year (from 1976) with a 2-week intravenous antipseudomonal course which included preferentially an aminoglycoside and a beta-lactam antibiotic. We investigated the development of antibiotic...... 1991 (100 strains). All the strains were screened and assayed semiquantitatively for beta-lactamase activity by use of nitrocefin. We found a significant (p < 0.005) increase in the MIC values of the P. aeruginosa strains against piperacillin and ceftazidime. However, no significant correlation was...... found between the MIC and the number of antipseudomonal courses of antibiotics. The proportion of resistant in vivo selected P. aeruginosa strains, presumed to be stably derepressed producers of chromosomal beta-lactamase, also increased significantly during the period studied. Our results confirm that...

  1. Emerging trends in epidemiology and management of infections caused by carbapenem-resistant Enterobacteriaceae.

    Science.gov (United States)

    Martirosov, Dmitriy M; Lodise, Thomas P

    2016-06-01

    The recent emergence and spread of infections caused by carbapenem-resistant Enterobacteriaceae (CRE) are concerning because carbapenems have represented a last line of defense against resistant strains of gram-negative pathogens. Existing therapies against CRE include tigecycline, the recently approved drug ceftazidime-avibactam, and older drugs not widely used in recent years, such as colistin, fosfomycin, and aminoglycosides. Best practices for use of the available drugs are not well defined. New therapeutic options with activity against CRE offer the opportunity to enhance our current approach to managing patients with infections due to CRE. The purpose of this report is to review the evolving epidemiology and treatment of infections due to CRE. As part of the treatment overview, this manuscript will discuss supportive data for antibiotics currently being used in the treatment of infections due to CRE, as well as those recently approved and in late-stage development. PMID:27033631

  2. Instrumental characterization of the smectite clay–gentamicin hybrids

    Indian Academy of Sciences (India)

    Alicja Rapacz-Kmita; Ewa Stodolak-Zych; Magdalena Ziabka; Agnieszka Rozycka; Magdalena Dudek

    2015-08-01

    This paper focusses on the intercalation of clay mineral with gentamicin (an aminoglycoside antibiotic). The smectite clay–gentamicin hybrids were prepared by a solution intercalation at 60°C and the process was carried out on unmodified smectite clay and on smectite after Na+ ionic activation. The resulting structural/microstructural properties and the potential for introducing gentamicin between smectite clay layers were investigated by means of X-ray diffraction, Fourier transform infrared spectroscopic techniques and transmission electron microscopy and scanning electron microscopy with energy-dispersive spectroscopy X-ray analysis. The results confirm the successful intercalation of gentamicin into the interlayer space of smectite clay, demonstrating that the material thus obtained could potentially be used as a drug carrier.

  3. Optimizing Guideline-Recommended Antibiotic Doses for Pediatric Infective Endocarditis.

    Science.gov (United States)

    Nichols, Kristen R; Israel, Emily N; Thomas, Christopher A; Knoderer, Chad A

    2016-05-01

    The American Heart Association recently published an updated scientific statement on the management of infective endocarditis in childhood. The recommendations included for vancomycin, aminoglycoside, and β-lactam dosing and monitoring are based primarily on expert opinion and do not consider available evidence for dose optimization based on pharmacokinetic and pharmacodynamic principles in pediatric patients. This is concerning because even when clinically necessary, some practitioners may be hesitant to deviate from guideline-recommended doses. In this perspective, we highlight potential areas for improvement in the statement-recommended doses and summarize evidence supporting antibiotic dosing optimization. The addition of a pediatric clinical pharmacist with expertise in antibiotic dosing to the panel would be beneficial for future updates. PMID:26917819

  4. 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.

  5. Clindamycin and gentamicin for aerobic and anaerobic sepsis.

    Science.gov (United States)

    Fass, R J; Ruiz, D E; Gardner, W G; Rotilie, C A

    1977-01-01

    Thirty-eight adult patients with serious pleuropulmonary, soft-tissue, bone, and intra-abdominal infections caused by combinations of aerobic, facultative, and anaerobic bacteria were treated with parenterally given clindamycin phosphate and gentamicin sulfate and surgery when appropriate. Nine had associated bacteremia. In 29, infections failed to respond to other therapeutic regimens, which included penicillins, cephalosporins, aminoglycosides, and chloramphenicol. Results with clindamycin and gentamicin were excellent and were attributed primarily to the activity of clindamycin against anaerobes, particularly Bacteroides fragilis. Serum concentrations of clindamycin surpassed by manyfold the minimal inhibitory concentrations (MICs) for anaerobes. Serum concentrations of gentamicin did not consistently surpass the MICs for Enterobacteriaceae and Pseudomonas aeruginosa, although those organisms were consistently gentamicinsusceptible by disk diffusion susceptibility tests. Persistent colonization with Enterobacteriaceae, P aeruginosa, enterococci, or Candida were common, and occasionally they were significant in prolonging the clinical courses of patients with extensive infections. PMID:318824

  6. Prevention of cisplatin nephrotoxicity

    Directory of Open Access Journals (Sweden)

    Hayati Fatemeh

    2016-01-01

    Full Text Available Cisplatin has a well-established role in the treatment of broad spectrum of malignancies; however its use is limited because of cisplatin-induced nephrotoxicity (CIN which can be progressive in more than 50% of cases. The most important risk factors for CIN include higher doses of cisplatin, previous cisplatin chemotherapy, underlying kidney damage and concurrent treatment with other potential nephrotoxin agents, such as aminoglycosides, nonsteroidal anti-inflammatory agents, or iodinated contrast media. Different strategies have been offered to diminish or prevent nephrotoxicity of cisplatin. The standard approach for prevention of CIN is the administration of lower doses of cisplatin in combination with full intravenous hydration prior and after cisplatin administration. Cisplatin-induced oxidative stress in the kidney may be prevented by natural antioxidant compounds. The results of this review show that many strategies for prevention of CIN exist, however, attention to the administration of these agent for CIN is necessary.

  7. Comparative Transduction Mechanisms of Vestibular Otolith Hair Cells

    Science.gov (United States)

    Baird, Richard A.

    1994-01-01

    Hair cells in the bullfrog vestibular otolith organs regenerate following aminoglycoside ototoxicity. Hair cells in these organs are differentially sensitive to gentamicin, with saccular hair cells and hair cells in the utricular striola being damaged at lower gentamicin concentrations than hair cells in the utricular extrastriola. Regenerating hair cells in these organs have short hair bundles and can be classified into a number of phenotypes using the same morphological criteria used to identify their mature counterparts. Our studies suggest that some supporting cells can convert, or transdifferentiate,into hair cells without an intervening cell division. By stimulating these processes in humans, clinicians may be able to alleviate human deafness and peripheral vestibular disorders by regenerating and replacing lost hair cells. In vivo and in vitro studies were done on cell proliferation and hair cell regeneration.

  8. BILATERAL MENIERE’S DISEASE IN THE YOUNG, DILEMMA’S IN MEDICAL MANAGEMENT: A CRITICAL REVIEW OF LITERATURE

    Directory of Open Access Journals (Sweden)

    Sahoo Kumar Anjan

    2015-04-01

    Full Text Available It is not very unusual for the ENT personnel to encounter cases of Meniere’s disease with bilateral ear involvement. As compared to unilateral cases the patient with bilateral involvement has more significant morbidity and emotional disturbance, particularly in young individuals. The present ambiguity in aetiology of the disease process has leaked to the management too and no definitive treatment options are described till date. The medical management at present is successful in controlling vertigo in the majority of the patients. But the symptoms of hearing loss and tinnitus are relatively less rehabilitated. The options of management like Aminoglycoside infusion and surgery have a limited role in cases with bilateral involvement and this drastically cripples the management protocol. The present review aims to evaluate the efficacy of individual agents and suggest a beneficial protocol based on the current literature.

  9. Parotitis due to anaerobic bacteria.

    Science.gov (United States)

    Matlow, A; Korentager, R; Keystone, E; Bohnen, J

    1988-01-01

    Although Staphylococcus aureus remains the pathogen most commonly implicated in acute suppurative parotitis, the pathogenic role of gram-negative facultative anaerobic bacteria and strict anaerobic organisms in this disease is becoming increasingly recognized. This report describes a case of parotitis due to Bacteroides disiens in an elderly woman with Sjögren's syndrome. Literature reports on seven additional cases of suppurative parotitis due to anaerobic bacteria are reviewed. Initial therapy of acute suppurative parotitis should include coverage for S. aureus and, in a very ill patient, coverage of gram-negative facultative organisms with antibiotics such as cloxacillin and an aminoglycoside. A failure to respond clinically to such a regimen or isolation of anaerobic bacteria should lead to the consideration of the addition of clindamycin or penicillin. PMID:3287567

  10. Livestock-Associated Methicillin Resistant and Methicillin Susceptible Staphylococcus aureus Sequence Type (CC)1 in European Farmed Animals: High Genetic Relatedness of Isolates from Italian Cattle Herds and Humans

    DEFF Research Database (Denmark)

    Alba, Patricia; Feltrin, Fabiola; Cordaro, Gessica;

    2015-01-01

    Italian dairy cattle herds. The aim of this study was to analyse the differences between ST1 MRSA and methicillin-susceptible S. aureus (MSSA) from cattle and pig herds in Italy and Europe and human isolates. Sixty-tree animal isolates from different holdings and 20 human isolates were characterized by...... pulsed-field gel electrophoresis (PFGE), spa-typing, SCCmec typing, and by micro-array analysis for several virulence, antimicrobial resistance, and strain/host-specific marker genes. Three major PFGE clusters were detected. The bovine isolates shared a high (>= 90% to 100%) similarity with human...... isolates and carried the same SCCmec type IVa. They often showed genetic features typical of human adaptation or present in human-associated CC1: Immune evasion cluster (IEC) genes sak and scn, or sea; sat and aphA3-mediated aminoglycoside resistance. Contrary, typical markers of porcine origin in Italy...

  11. Lactobacillus species: taxonomic complexity and controversial susceptibilities.

    Science.gov (United States)

    Goldstein, Ellie J C; Tyrrell, Kerin L; Citron, Diane M

    2015-05-15

    The genus Lactobacillus is a taxonomically complex and is composed of over 170 species that cannot be easily differentiated phenotypically and often require molecular identification. Although they are part of the normal human gastrointestinal and vaginal flora, they can also be occasional human pathogens. They are extensively used in a variety of commercial products including probiotics. Their antimicrobial susceptibilities are poorly defined in part because of their taxonomic complexity and are compounded by the different methods recommended by Clinical Laboratory Standards Institute and International Dairy Foundation. Their use as probiotics for prevention of Clostridium difficile infection is prevalent among consumers worldwide but raises the question of will the use of any concurrent antibiotic effect their ability to survive. Lactobacillus species are generally acid resistant and are able to survive ingestion. They are generally resistant to metronidazole, aminoglycosides and ciprofloxacin with L. acidophilus being susceptible to penicillin and vancomycin, whereas L. rhamnosus and L. casei are resistant to metronidazole and vancomycin. PMID:25922408

  12. Cowpea [Vigna unguiculata (L.) Walp].

    Science.gov (United States)

    Behura, Ratikanta; Kumar, Sanjeev; Saha, Bedabrata; Panda, Manasa Kumar; Dey, Mohitosh; Sadhukhan, Ayan; Mishra, Sagarika; Alam, Shamsher; Sahoo, Debee Prasad; Sugla, Twinkle; Sahoo, Lingaraj

    2015-01-01

    Agrobacterium tumefaciens-mediated transformation is an efficient method for incorporating genes and recovering stable transgenic plants in cowpea because this method offers several advantages such as the defined integration of transgenes, potentially low copy number, and preferential integration into transcriptional active regions of the chromosome. Cotyledonary node explants of cowpea present an attractive target for T-DNA delivery followed by regeneration of shoots via axillary proliferation without involvement of a de novo regeneration pathway. In this chapter, we describe a detailed protocol for Agrobacterium-mediated transformation of the cowpea variety Pusa Komal. The seedling cotyledonary node explants are used for cocultivation with an Agrobacterium strain EHA105 harboring standard binary vector, pCAMBIA2301 or pNOV2819, and putative transformed plants are selected using aminoglycoside antibiotic or mannose as sole carbon source, respectively. The entire process includes explant infection to transgenic seed generation in greenhouse. PMID:25300846

  13. Imipenem resistance in nonfermenters causing nosocomial urinary tract infections.

    Directory of Open Access Journals (Sweden)

    Taneja N

    2003-07-01

    Full Text Available Nonfermenting gram-negative bacilli (nonfermenters have emerged as important nosocomial pathogens causing opportunistic infections in immunocompromised hosts. These organisms show high level of resistance to b-lactam agents, fluoroquinolones and aminoglycosides. Imipenem is a carbapenem antibiotic, which can be very useful for treatment of infections caused by nonfermenters. Eighty-five nonfermenters causing nosocomial UTI were tested for MIC to imipenem by agar dilution method. Resistance to other antimicrobial agents was compared between imipenem sensitive (S and resistance (R groups. Overall 36.4% of nonfermenters were resistant to imipenem. Forty two percent of P. aeruginosa and 18.5% of Acinetobacter baumanii were imipenem resistant. Other nonfermenters showed variable resistance, resistance in Alcaligenes spp. being very high. More than 70% of the nonfermenters were resistant to ceftazidime, gentamicin and ciprofloxacin. Piperacillin and amikacin had the best in vitro susceptibility. No significant difference was found in the antibiotic susceptibility profile among imipenem sensitive (S or resistant (R strains.

  14. AFRRI reports. First Quarter, January-March 1991. Scientific report

    Energy Technology Data Exchange (ETDEWEB)

    1991-04-01

    Ionizing radiation reduces the host's defenses to infection (1) and enhances its susceptibility to systemic infection due to endogenous and exogenous organisms. Klebsiella pneumoniae is one of the most frequent causes of gram-negative bacteremia, and is especially prevalent in immunocompromised patients. Therapy for severe systemic infection due to gram-negative bacteria generally involves the use of aminoglycosides in combination with beta lactam antibiotics. However, several recently developed quinolone compounds have exhibited high in vitro bactericidal activity against most gram negative bacteria. including K. pneumoniae. In this study, the authors evaluated the efficacy of oral therapy with several quinolones in a model of experimental septicemia due to orally ingested K pneumoniae in irradiated mice.

  15. Isolation,Identification and Antibiotics Susceptibility Test of Citrobacter freundii from Procambarus clarkia

    Institute of Scientific and Technical Information of China (English)

    Chen; Honglian; Song; Guangtong; He; Jixiang; Hou; Guanjun; Wang; Yongjie

    2014-01-01

    This experiment was conducted to clarify species and drug resistance of pathogen from the diseased Procambarus clarkia. Pathogenic bacteria from hepatopancreas of the diseased P. clarkia were examined using conventional methods,and then were isolated. The further tests and analysis of the isolated strain were developed,including the regression experiment to P. clarkia,the morphology,physiological and biochemical characteristics,sequence analysis of their 16 S rRNA and gyr B genes,and the susceptibility test to antibiotics. Large colonies with similar morphology and color were obtained. Strain X120523 was identified as Citrobacter freundii,proved to have strong pathogenicity,and was susceptible to quinolones and aminoglycosides.

  16. Draft Genome Sequence of Proteus mirabilis NO-051/03, Representative of a Multidrug-Resistant Clone Spreading in Europe and Expressing the CMY-16 AmpC-Type β-Lactamase.

    Science.gov (United States)

    D'Andrea, Marco Maria; Giani, Tommaso; Henrici De Angelis, Lucia; Ciacci, Nagaia; Gniadkowski, Marek; Miriagou, Vivi; Torricelli, Francesca; Rossolini, Gian Maria

    2016-01-01

    Proteus mirabilis NO-051/03, representative of a multidrug-resistant clone expressing the CMY-16 AmpC-type β-lactamase and circulating in Europe since 2003, was sequenced by a MiSeq platform using a paired-end approach. The genome was assembled in 100 scaffolds with a total length of 4,197,318 bp. Analysis of the draft genome sequence revealed the presence of several acquired resistance determinants to β-lactams, aminoglycosides, phenicols, tetracyclines, trimethoprim, and sulfonamides, of one plasmid replicon, and of a type I-E clustered regularly interspaced short palindromic repeat (CRISPR)-associated protein (Cas) adaptive immune system. PMID:26868393

  17. Synthesis and properties of vitamin E analog-conjugated neomycin for delivery of RNAi drugs to liver cells.

    Science.gov (United States)

    Iwata, Rintaro; Nakayama, Futoshi; Hirochi, Sakie; Sato, Kazuki; Piao, Wenying; Nishina, Kazutaka; Yokota, Takanori; Wada, Takeshi

    2015-02-15

    RNA interference (RNAi) is a promising tool to regulate gene expression by external double stranded RNAs (dsRNAs) such as siRNAs. As an efficient method to deliver siRNAs to liver cells, we propose a novel strategy using vitamin E (VE)-conjugated neomycin derivatives. With the aim of delivering RNAi-based drugs to liver cells, several tripod-type and prodrug-type neomycin derivatives were synthesized, all of which were thermodynamically stabilized RNA duplexes. The prodrug-type derivative 7 and the tripod-type derivative 10 were delivered to liver cancer cells and successfully induced RNAi activity. These results indicated the potential use of natural aminoglycosides as carriers of RNAi drugs. PMID:25597008

  18. Controlling infection and spread of carbapenems-resistant Klebsiella pneumoniae among burn patients%控制烧伤患者抗碳青霉烯类抗生素肺炎克雷伯菌的感染和传播

    Institute of Scientific and Technical Information of China (English)

    郇京宁

    2015-01-01

    The emergence and spread of carbapenemsresistant Klebsiella pneumoniae (CRKP) in burn ward is an important threat to burn management.CRKP isolates are resistant to almost all available antibiotics and are susceptible only to polymyxins and tigecycline.The mechanism of the drug resistance of CRKP is associated with the plasmid-encoded carbapenemase Klebsiella pneumoniae carbapenemase (KPC),a carbapenemhydrolyzing β-lactamase.Antibiotics which can currently be used to treat CRKP infection include polymyxins,tigecycline,and some aminoglycosides.The efficacy of using antibiotics in combination is better than that of single-agent therapy for the treatment of CRKP infection in bloodstream.In order to control CRKP infection in burn patients,strategies for preventing CRKP dissemination in burn ward are strongly advocated.

  19. Nocardia transvalensis Disseminated Infection in an Immunocompromised Patient with Idiopathic Thrombocytopenic Purpura

    Directory of Open Access Journals (Sweden)

    Jorge García-Méndez

    2016-01-01

    Full Text Available Nocardia transvalensis complex includes a wide range of microorganisms with specific antimicrobial resistance patterns. N. transvalensis is an unusual Nocardia species. However, it must be differentiated due to its natural resistance to aminoglycosides while other Nocardia species are susceptible. The present report describes a Nocardia species involved in an uncommon clinical case of a patient with idiopathic thrombocytopenic purpura and pulmonary nocardiosis. Microbiological and molecular techniques based on the sequencing of the 16S rRNA gene allowed diagnosis of Nocardia transvalensis sensu stricto. The successful treatment was based on trimethoprim-sulfamethoxazole and other drugs. We conclude that molecular identification of Nocardia species is a valuable technique to guide good treatment and prognosis and recommend its use for daily bases diagnosis.

  20. Characterization of class 1 integrons associated with R-plasmids in clinical Aeromonas salmonicida isolates from various geographical areas

    DEFF Research Database (Denmark)

    Schmidt, A.S.; Bruun, Morten Sichlau; Larsen, J.L.; Dalsgaard, Inger

    2001-01-01

    Class 1 integrons were found in 26 of 40 antibiotic-resistant isolates of the fish pathogen Aeromonas salmonicida from Northern Europe and North America. Three different dhfr genes, conferring trimethoprim resistance, and one ant(3 " )1a aminoglycoside resistance gene were identified as gene...... inserts. The gene cassettes tended to be conserved among isolates from a particular geographical area. Nineteen isolates transferred R- plasmids carrying different tet determinants to Escherichia coli in filter mating assays, and in 15 cases, the class 1 integrons were co-transferred. Transferable...... sulphadiazine, trimethoprim and streptomycin resistances were invariably encoded by integrons. It thus appears that integron-encoded antibiotic resistance genes contribute substantially to the horizontal spread of antimicrobial resistance within this species, being associated with conjugative plasmids....

  1. Emerging broad-spectrum resistance in Pseudomonas aeruginosa and Acinetobacter baumannii: Mechanisms and epidemiology.

    Science.gov (United States)

    Potron, Anaïs; Poirel, Laurent; Nordmann, Patrice

    2015-06-01

    Multidrug resistance is quite common among non-fermenting Gram-negative rods, in particular among clinically relevant species including Pseudomonas aeruginosa and Acinetobacter baumannii. These bacterial species, which are mainly nosocomial pathogens, possess a diversity of resistance mechanisms that may lead to multidrug or even pandrug resistance. Extended-spectrum β-lactamases (ESBLs) conferring resistance to broad-spectrum cephalosporins, carbapenemases conferring resistance to carbapenems, and 16S rRNA methylases conferring resistance to all clinically relevant aminoglycosides are the most important causes of concern. Concomitant resistance to fluoroquinolones, polymyxins (colistin) and tigecycline may lead to pandrug resistance. The most important mechanisms of resistance in P. aeruginosa and A. baumannii and their most recent dissemination worldwide are detailed here. PMID:25857949

  2. Fatal septicemia by multidrug-resistant Enterococcus faecium in a case of exomphalos minor

    Directory of Open Access Journals (Sweden)

    Mahantesh V Parande

    2012-01-01

    Full Text Available Exomphalos minor is one among uncommon disorders of the umbilical region. Here, we report a fatal case of exomphalos minor with enterococcal septicemia. A male baby, born with exomphalos minor, developed clinical features of septicemia on the fourth postnatal day. Blood samples were collected by venepuncture from two sites for culture. Enterococcus faecium was isolated from both the blood samples. The swabs collected from the site of exomphalos also yielded growth of Enterococcus faecium, confirming the source of infection. The antibiogram with Minimum Inhibitory Concentrations (MIC for various antibiotics was done for isolates from all three sites, which was similar. The isolate was resistant to multiple antibiotics with high level aminoglycoside resistance. The baby was treated with antibiotics and other supportive measures. However, the baby succumbed to the septicemia. As per our knowledge, this is the first reported case of fatal septicemia by multidrug-resistant Enterococcus faecium in a case of exomphalos minor.

  3. Pasteurella canis Isolation following Penetrating Eye Injury: A Case Report.

    Science.gov (United States)

    Rashid, Noor-Khairul; Zam, Zarifah; Mdnoor, Siti-Suraya; Siti-Raihan, Ishak; Azhany, Yaakub

    2012-01-01

    A 3-year-old boy presented with history of trauma to the left eye after he accidentally injured his eye with a broom stick made up from coconut skewers. There was history of cats as their pets but not dogs. Ocular examination revealed left superonasal conjunctival laceration and scleral perforation with prolapsed vitreous. Fundus examination showed minimal vitreous haemorrhage and flat retina. Conjunctiva swab at the wound site was sent for gram staining, culture, and sensitivity. He underwent scleral suturing, vitreous tap, and intravitreal injection of Ceftazidime and Amikacin. Vitreous tap was sent for gram stained, culture and sensitivity. Postoperatively, he was started empirically on IV Ciprofloxacin 160 mg BD, Guttae Ciprofloxacin, and Guttae Ceftazidime. Conjunctiva swab grew Pasteurella canis which was sensitive to all Beta lactams, Ciprofloxacin, Chloramphenicol, and Aminoglycoside. Post-operative was uneventful, absent signs of endophthalmitis or orbital cellulitis. PMID:22606491

  4. 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. PMID:20482280

  5. X-ray Analyses of the Ribosomal A-Site Molecular Switches

    Science.gov (United States)

    Kondo, Jiro

    The aminoacyl-tRNA decoding site (A-site) on the small ribosomal subunit is an RNA molecular switch guaranteeing high translation fidelity. Due to the similarity of the secondary structure of the A-site, it has long been believed that the functional characteristics and tertiary structure of the A-site molecular switch are basically conserved in three main cell types, bacteria, mitochondria and eukaryotic cytoplasm. However, these three cell types are noticeably different in their biological properties such as life cycle, genome size, structural component of ribosome and number of tRNA species. In our structural studies, we have shown how a small difference of nucleotide sequences affects the dynamics of the A-site molecular switches underlying the decoding mechanism adapted to their biological properties and environments. The observed structural insights into the decoding process allowed us to understand molecular mechanisms of non-syndromic hearing loss and toxicity mechanism of aminoglycoside antibiotics.

  6. Pseudomonas Aeruginosa Resistance Phenotypes and Phenotypic Highlighting Methods

    Science.gov (United States)

    BĂLĂŞOIU, MARIA; BĂLĂŞOIU, A.T.; MĂNESCU, RODICA; AVRAMESCU, CARMEN; IONETE, OANA

    2014-01-01

    Pseudomonas aeruginosa genus bacteria are well known for their increased drug resistance (phenotypic ang genotypic resistance). The most important resistance mechanisms are: enzyme production, reduction of pore expression, reduction of the external membrane proteins expression, efflux systems, topoisomerase mutations. These mechanisms often accumulate and lead to multidrug ressitance strains emergence. The most frequent acquired resistance mechanisms are betalactamase-type enzyme production (ESBLs, AmpC, carbapenemases), which determine variable phenotypes of betalactamines resistance, phenotypes which are associated with aminoglycosides and quinolones resistance. The nonenzymatic drug resistance mechanisms are caused by efflux systems, pore reduction and penicillin-binding proteins (PBP) modification, which are often associated to other resistance mechanisms. Phenotypic methods used for testing these mechanisms are based on highlighting these phenotypes using Kirby Bauer antibiogram, clinical breakpoints, and “cut off” values recommended by EUCAST 2013 standard, version 3.1. PMID:25729587

  7. A small molecule microarray platform to select RNA internal loop-ligand interactions.

    Science.gov (United States)

    Childs-Disney, Jessica L; Wu, Meilan; Pushechnikov, Alexei; Aminova, Olga; Disney, Matthew D

    2007-11-20

    Herein, we report the development of a microarray platform to select RNA motif-ligand interactions that allows simultaneous screening of both RNA and chemical space. We used this platform to identify the RNA internal loops that bind 6'- N-5-hexynoate kanamycin A ( 1). Selected internal loops that bind 1 were studied in detail and commonly display an adenine across from a cytosine independent of the size of the loop. Additional preferences are also observed. For 3 x 3 nucleotide loops, there is a preference for purines, and for 2 x 2 nucleotide loops there is a preference for pyrimidines neighbored by an adenine across from a cytosine. This technique has several advantageous features for selecting RNA motif-ligand interactions: (1) higher affinity RNA motif-ligand interactions are identified by harvesting bound RNAs from lower ligand loadings; (2) bound RNAs are harvested from the array via gel extraction, mitigating kinetic biases in selections; and (3) multiple selections are completed on a single array surface. To further demonstrate that multiple selections can be completed in parallel on the same array surface, we selected the RNA internal loops from a 4096-member RNA internal loop library that bound a four-member aminoglycoside library. These experiments probed 16,384 (4 aminoglycoside x 4096-member RNA library) interactions in a single experiment. These studies allow for parallel screening of both chemical and RNA space to improve our understanding of RNA-ligand interactions. This information may facilitate the rational and modular design of small molecules targeting RNA. PMID:17975888

  8. Survey on antimicrobial resistance patterns in Vibrio vulnificus and Vibrio cholerae non-O1/non-O139 in Germany reveals carbapenemase-producing Vibrio cholerae in coastal waters.

    Science.gov (United States)

    Bier, Nadja; Schwartz, Keike; Guerra, Beatriz; Strauch, Eckhard

    2015-01-01

    An increase in the occurrence of potentially pathogenic Vibrio species is expected for waters in Northern Europe as a consequence of global warming. In this context, a higher incidence of Vibrio infections is predicted for the future and forecasts suggest that people visiting and living at the Baltic Sea are at particular risk. This study aimed to investigate antimicrobial resistance patterns among Vibrio vulnificus and Vibrio cholerae non-O1/non-O139 isolates that could pose a public health risk. Antimicrobial susceptibility of 141 V. vulnificus and 184 V. cholerae non-O1/non-O139 strains isolated from German coastal waters (Baltic Sea and North Sea) as well as from patients and retail seafood was assessed by broth microdilution and disk diffusion. Both species were susceptible to most of the agents tested (12 subclasses) and no multidrug-resistance was observed. Among V. vulnificus isolates, non-susceptibility was exclusively found toward aminoglycosides. In case of V. cholerae, a noticeable proportion of strains was non-susceptible to aminopenicillins and aminoglycosides. In addition, resistance toward carbapenems, quinolones, and folate pathway inhibitors was sporadically observed. Biochemical testing indicated the production of carbapenemases with unusual substrate specificity in four environmental V. cholerae strains. Most antimicrobial agents recommended for treatment of V. vulnificus and V. cholerae non-O1/non-O139 infections were found to be effective in vitro. However, the occurrence of putative carbapenemase producing V. cholerae in German coastal waters is of concern and highlights the need for systematic monitoring of antimicrobial susceptibility in potentially pathogenic Vibrio spp. in Europe. PMID:26579088

  9. Expression of the RND-type efflux pump AdeABC in Acinetobacter baumannii is regulated by the AdeRS two-component system.

    Science.gov (United States)

    Marchand, Isabelle; Damier-Piolle, Laurence; Courvalin, Patrice; Lambert, Thierry

    2004-09-01

    The AdeABC pump of Acinetobacter baumannii BM4454, which confers resistance to various antibiotic classes including aminoglycosides, is composed of the AdeA, AdeB, and AdeC proteins; AdeB is a member of the RND superfamily. The adeA, adeB, and adeC genes are contiguous and adjacent to adeS and adeR, which are transcribed in the opposite direction and which specify proteins homologous to sensors and regulators of two-component systems, respectively (S. Magnet, P. Courvalin, and T. Lambert, Antimicrob. Agents Chemother. 45:3375-3380, 2001). Analysis by Northern hybridization indicated that the three genes were cotranscribed, although mRNAs corresponding to adeAB and adeC were also present. Cotranscription of the two regulatory genes was demonstrated by reverse transcription-PCR. Inactivation of adeS led to aminoglycoside susceptibility. Transcripts corresponding to adeAB were not detected in susceptible A. baumannii CIP 70-10 but were present in spontaneous gentamicin-resistant mutants obtained in vitro. Analysis of these mutants revealed the substitutions Thr153-->Met in AdeS downstream from the putative His-149 site of autophosphorylation, which is presumably responsible for the loss of phosphorylase activity by the sensor, and Pro116-->Leu in AdeR at the first residue of the alpha(5) helix of the receiver domain, which is involved in interactions that control the output domain of response regulators. These mutations led to constitutive expression of the pump and, thus, to antibiotic resistance. These data indicate that the AdeABC pump is cryptic in wild A. baumannii due to stringent control by the AdeRS two-component system. PMID:15328088

  10. Activity of tigecycline tested against a global collection of Enterobacteriaceae, including tetracycline-resistant isolates.

    Science.gov (United States)

    Fritsche, Thomas R; Strabala, Patty A; Sader, Helio S; Dowzicky, Michael J; Jones, Ronald N

    2005-07-01

    Steadily increasing resistance among the Enterobacteriaceae to beta-lactams, fluoroquinolones, aminoglycosides, tetracyclines, and trimethoprim/sulfamethoxazole has compromised the utility of these commonly used antimicrobial classes for many community- or hospital-acquired infections. The development of tigecycline, the sentinel representative of a novel class of broad-spectrum agents (the glycylcyclines), represents an important milestone in addressing this critical need. Resistance to tigecycline might be expected to occur via the same mechanisms that produce tetracycline resistance; however, tigecycline remains stable and largely unaffected by the commonly occurring efflux and ribosomal protection resistance mechanisms. In this study, an international collection of Enterobacteriaceae (11327 isolates; 32.8% tetracycline-resistant) from global surveillance studies (2000-2004) were evaluated against tigecycline and other comparator antimicrobials. Although the most active agents were the carbapenems and aminoglycosides (97.5-99.7% susceptible), tigecycline displayed high potency (MIC50 and MIC90, 0.25 and 1 microg/mL) with 95.7% of all strains being inhibited at agglomerans; and up to 4-fold for Klebsiella spp., Enterobacter spp., and Citrobacter spp.). Among E. coli (263 isolates) and Klebsiella spp. (356) that meet recognized screening definitions for extended-spectrum beta-lactamase production, 100.0% and 94.4% were inhibited by tigecycline at 2 microg/mL, respectively. These findings confirm that tigecycline exhibits potency, breadth of spectrum, and stability to the commonly occurring resistance mechanisms found in contemporary Enterobacteriaceae isolates, attributes that make this parenteral agent an attractive candidate for use against serious infections produced by these species. PMID:16105566

  11. MALDI-TOF MS as a Tool To Detect a Nosocomial Outbreak of Extended-Spectrum-β-Lactamase- and ArmA Methyltransferase-Producing Enterobacter cloacae Clinical Isolates in Algeria

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    Khennouchi, Nour Chems el Houda; Loucif, Lotfi; Boutefnouchet, Nafissa; Allag, Hamoudi

    2015-01-01

    Enterobacter cloacae is among the most important pathogens responsible for nosocomial infections and outbreaks. In this study, 77 Enterobacter isolates were collected: 27 isolates from Algerian hospitals (in Constantine, Annaba, and Skikda) and 50 isolates from Marseille, France. All strains were identified by matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS). Antibiotic susceptibility testing was performed by the disk diffusion method. PCR was used to detect extended-spectrum-beta-lactamase (ESBL)-encoding, fluoroquinolone resistance-encoding, and aminoglycoside-modifying enzyme (AME) genes. Epidemiological typing was performed using MALDI-TOF MS with data mining approaches, along with multilocus sequence typing (MLST). Sixty-eight isolates (27 from Algeria, 41 from Marseille) were identified by MALDI-TOF MS as E. cloacae. Resistance to antibiotics in the Algerian isolates was significantly higher than that in the strains from Marseille, especially for beta-lactams and aminoglycosides. Eighteen of the 27 Algerian isolates and 11 of the 41 Marseille isolates possessed at least one ESBL-encoding gene: blaCTX-M and/or blaTEM. AME genes were detected in 20 of the 27 Algerian isolates and 8 of the 41 Marseille isolates [ant(2″)-Ia, aac(6′)-Ib-cr, aadA1, aadA2, and armA]. Conjugation experiments showed that armA was carried on a transferable plasmid. MALDI-TOF typing showed three separate clusters according to the geographical distribution and species level. An MLST-based phylogenetic tree showed a clade of 14 E. cloacae isolates from a urology unit clustering together in the MALDI-TOF dendrogram, suggesting the occurrence of an outbreak in this unit. In conclusion, the ability of MALDI-TOF to biotype strains was confirmed, and surveillance measures should be implemented, especially for Algerian patients hospitalized in France. PMID:26239991

  12. Mannitol enhances antibiotic sensitivity of persister bacteria in Pseudomonas aeruginosa biofilms.

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    Nicolas Barraud

    Full Text Available The failure of antibiotic therapies to clear Pseudomonas aeruginosa lung infection, the key mortality factor for cystic fibrosis (CF patients, is partly attributed to the high tolerance of P. aeruginosa biofilms. Mannitol has previously been found to restore aminoglycoside sensitivity in Escherichia coli by generating a proton-motive force (PMF, suggesting a potential new strategy to improve antibiotic therapy and reduce disease progression in CF. Here, we used the commonly prescribed aminoglycoside tobramycin to select for P. aeruginosa persister cells during biofilm growth. Incubation with mannitol (10-40 mM increased tobramycin sensitivity of persister cells up to 1,000-fold. Addition of mannitol to pre-grown biofilms was able to revert the persister phenotype and improve the efficacy of tobramycin. This effect was blocked by the addition of a PMF inhibitor or in a P. aeruginosa mutant strain unable to metabolise mannitol. Addition of glucose and NaCl at high osmolarity also improved the efficacy of tobramycin although to a lesser extent compared to mannitol. Therefore, the primary effect of mannitol in reverting biofilm associated persister cells appears to be an active, physiological response, associated with a minor contribution of osmotic stress. Mannitol was tested against clinically relevant strains, showing that biofilms containing a subpopulation of persister cells are better killed in the presence of mannitol, but a clinical strain with a high resistance to tobramycin was not affected by mannitol. Overall, these results suggest that in addition to improvements in lung function by facilitating mucus clearance in CF, mannitol also affects antibiotic sensitivity in biofilms and does so through an active, physiological response.

  13. Profile of urinary tract infections in paediatric patients

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    Palak Gupta

    2015-01-01

    Full Text Available Background & objectives: This cross-sectional study was conducted at a tertiary care centre in Puducherry, south India, with the aim of finding the profile of the paediatric urinary tract infection (UTI, bacterial pathogens involved, and also to observe vesicoureteric reflux (VUR and renal scarring in these patients. Methods: A total of 524 paediatric patients ≤13 yr, suspected to have UTI, were included in the study. Urine samples were collected, processed for uropathogen isolation and antibiotic susceptibility test was performed as per the Clinical and Laboratory Standards Institute (CLSI guidelines. Thirty two culture proven children with UTI underwent micturating cysto-urethrography (MCU and dimercaptosuccinic acid (DMSA scanning was done for 69 children. Results: o0 f the 524 children, 186 (35.4% had culture proven UTI with 105 (56.4% being infants, 50 (27.4% between 1-5 yr, 30 (16.12% between 5-13 yr and 129 (69.35% males. Posterior urethral valve (PUV was noted in three, hydronephrosis in one, VUR in 18 and renal scarring in 33. VUR as well as renal scarring were more in males >1 yr of age. A significant association (P=0.0054 was noted with a combined sensitivity and specificity of these investigations being 83 and 90 per cent, respectively of the MCU and DMSA scans for detecting VUR. Escherichia coli was the most common pathogen isolated, sensitive to nitrofurantoin, followed by cefoperazone-sulbactam, aminoglycosides and meropenem. Interpretation & conclusions: Our results indicate that UTI varies with age and gender and extensive evaluation is required in boys under one year of age with UTI. This study also highlights the better efficacy of aminoglycosides, cefoperazone-sulbactam and nitrofurantoin in vitro compared with meropenem in Gram-negative uropathogens.

  14. Pattern of antimicrobial usage in livestock animals in south-western Nigeria: The need for alternative plans

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    Hezekiah K. Adesokan

    2015-02-01

    Full Text Available Resistance to antibiotics has continued to increase, placing future animal and human disease management in real danger. The developing countries characterised by widespread indiscriminate antibiotic use and in which ‘third-generation’ antibiotics are not readily available or affordable are the worst affected. A 3-year (2010–2012 retrospective survey of antibiotic usage in livestock production in three selected states of south-western Nigeria was conducted. Data obtained from eight purposively selected licensed veterinary pharmaceutical sales establishments in the area, based on keeping detailed sales records for the study period, were analysed using Stata Version 12. Results showed that tetracyclines (33.6%, fluoroquinolones (26.5% and beta-lactams/aminoglycosides (20.4% constituted the majority of the antibiotics used over the 3 years. The differences in the quantities of antibiotic types used within each antimicrobial class were statistically significant for tetracyclines (F = 59.87; p < 0.0001 and fluoroquinolones (F = 43.97; p < 0.0001 but not for beta-lactams/aminoglycosides (F = 3.21; p = 0.148. Furthermore, antibiotic consumption increased by 40.4% between 2010 and 2012. Although statistically insignificant (F = 0.277; p = 0.762, the increasing trend across the years was at rates of 23.5% between 2010 and 2011 and 13.8% between 2011 and 2012. In addition, the findings show a significantly higher consumption rate (t = 15.21; df = 5; p < 0.0001 during the rainy (52.5% than the dry (47.5% seasons. The current increasing trend in antibiotic usage holds a serious danger for the future and therefore calls for alternative plans to safeguard future livestock production, food security and human health. This becomes more imperative considering emerging resistance against tetracyclines and fluoroquinolones, the foremost remedies for livestock diseases in most developing countries.

  15. MALDI-TOF MS as a Tool To Detect a Nosocomial Outbreak of Extended-Spectrum-β-Lactamase- and ArmA Methyltransferase-Producing Enterobacter cloacae Clinical Isolates in Algeria.

    Science.gov (United States)

    Khennouchi, Nour Chems el Houda; Loucif, Lotfi; Boutefnouchet, Nafissa; Allag, Hamoudi; Rolain, Jean-Marc

    2015-10-01

    Enterobacter cloacae is among the most important pathogens responsible for nosocomial infections and outbreaks. In this study, 77 Enterobacter isolates were collected: 27 isolates from Algerian hospitals (in Constantine, Annaba, and Skikda) and 50 isolates from Marseille, France. All strains were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Antibiotic susceptibility testing was performed by the disk diffusion method. PCR was used to detect extended-spectrum-beta-lactamase (ESBL)-encoding, fluoroquinolone resistance-encoding, and aminoglycoside-modifying enzyme (AME) genes. Epidemiological typing was performed using MALDI-TOF MS with data mining approaches, along with multilocus sequence typing (MLST). Sixty-eight isolates (27 from Algeria, 41 from Marseille) were identified by MALDI-TOF MS as E. cloacae. Resistance to antibiotics in the Algerian isolates was significantly higher than that in the strains from Marseille, especially for beta-lactams and aminoglycosides. Eighteen of the 27 Algerian isolates and 11 of the 41 Marseille isolates possessed at least one ESBL-encoding gene: blaCTX-M and/or blaTEM. AME genes were detected in 20 of the 27 Algerian isolates and 8 of the 41 Marseille isolates [ant(2″)-Ia, aac(6')-Ib-cr, aadA1, aadA2, and armA]. Conjugation experiments showed that armA was carried on a transferable plasmid. MALDI-TOF typing showed three separate clusters according to the geographical distribution and species level. An MLST-based phylogenetic tree showed a clade of 14 E. cloacae isolates from a urology unit clustering together in the MALDI-TOF dendrogram, suggesting the occurrence of an outbreak in this unit. In conclusion, the ability of MALDI-TOF to biotype strains was confirmed, and surveillance measures should be implemented, especially for Algerian patients hospitalized in France. PMID:26239991

  16. Survey on antimicrobial resistance patterns in Vibrio vulnificus and Vibrio cholerae non-O1/non-O139 in Germany reveals carbapenemase-producing Vibrio cholerae in coastal waters

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    Nadja eBier

    2015-10-01

    Full Text Available An increase in the occurrence of potentially pathogenic Vibrio species is expected for waters in Northern Europe as a consequence of global warming. In this context, a higher incidence of Vibrio infections is predicted for the future and forecasts suggest that people visiting and living at the Baltic Sea are at particular risk.This study aimed to investigate antimicrobial resistance patterns among Vibrio vulnificus and Vibrio cholerae non-O1/non-O139 isolates that could pose a public health risk. Antimicrobial susceptibility of 141 V. vulnificus and 184 V. cholerae non-O1/non-O139 strains isolated from German coastal waters (Baltic Sea and North Sea as well as from patients and retail seafood was assessed by broth microdilution and disk diffusion. Both species were susceptible to most of the agents tested (12 subclasses and no multidrug-resistance was observed. Among V. vulnificus isolates, non-susceptibility was exclusively found towards aminoglycosides. In case of V. cholerae, a noticeable proportion of strains was non-susceptible to aminopenicillins and aminoglycosides. In addition, resistance towards carbapenems, quinolones, and folate pathway inhibitors was sporadically observed. Biochemical testing indicated the production of carbapenemases with unusual substrate specificity in four environmental V. cholerae strains. Most antimicrobial agents recommended for treatment of V. vulnificus and V. cholerae non-O1/non-O139 infections were found to be effective in vitro. However, the occurrence of putative carbapenemase producing V. cholerae in German coastal waters is of concern and highlights the need for systematic monitoring of antimicrobial susceptibility in potentially pathogenic Vibrio spp. in Europe.

  17. Molecular identification of multi drug resistant bacteria from urinary tract infected urine samples.

    Science.gov (United States)

    Kumar, M S; Das, A P

    2016-09-01

    Urinary tract infections (UTIs) are of great concern in both developing and developed countries all over the world. Even though the infections are more common in women and children, they are at a considerable rate in men and of all ages. The uropathogens causing the infections are spread through various routes. The treatment generally recommended by the physicians is antibiotic usage. But, most of the uropathogens have evolved antibiotic resistance mechanisms. This makes the present situation hectic in control and prevention of UTIs. The present study aims to illustrate the multidrug resistance patterns among isolated bacterial strains from infected urine samples in Odisha state, India. Four bacterial strains were isolated and identified as Proteus sp. SK3, Pseudomonas sp. ADMK77, Proteus sp. BLKB2 and Enterobacter hormaechei strain CW-3 by 16S rRNA gene sequencing. Phylogenetc analysis indicated the strains belong to three various genera namely, Proteus, Pseudomonas and Enterobacter. The evolutionary timeline of the bacteria was studied by constructing phylogenetic trees by Neighborhood Joining method. The presence of ESBL gene and biofilm forming capability were studied for the four strains. Antibiotic susceptibility patterns of the isolates were studied toward the commonly recommended antibiotics. Both the Proteus strains were found commonly susceptible to aminoglycoside and sulphonamide groups. Pseudomonas strain was found to be susceptible to cephems, aminoglycosides and fluoroquinolones. Enterobacter sp was found to be resistant to almost all antibiotic groups and susceptible to only sulphonamides group. The antibiotic susceptibility patterns of the bacteria help in choosing the empirical antibiotic treatment for UTI. PMID:27354209

  18. Frequency of conjugative transfer of plasmid-encoded ISEcp1 - blaCTX-M-15 and aac(6'-lb-cr genes in Enterobacteriaceae at a tertiary care center in Lebanon - role of transferases

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    Araj George F

    2010-07-01

    Full Text Available Abstract Background The frequency of transfer of genes encoding resistance to antimicrobial agents was determined by conjugation in ESBL-producing and/or fluoroquinolone or aminoglycoside resistant Enterobacteriaceae clinical isolates at a tertiary care center in Lebanon. In addition, the role of tra genes encoding transferases in mediating conjugation was assessed. Methods Conjugation experiments were done on 53 ESBL-producing and/or fluoroquinolone resistant E. coli and K. pneumoniae and ESBL-producing S. sonnei isolates. Antimicrobial susceptibility testing on parent and transconjugant isolates, and PCR amplifications on plasmid extracts of the resistance-encoding genes: blaCTX-M-15 with the ISEcp1 insertion sequence, the aac(6'-lb-cr and qnrS genes, as well as tra encoding transferases genes were done. Random amplified polymorphic DNA (RAPD analysis was performed to demonstrate whether conjugative isolates are clonal and whether they are linked epidemiologically to a particular source. Results Antimicrobial susceptibility testing on transconjugants revealed that 26 out of 53 (49% ESBL-producing Enterobacteriaceae were able to transfer antimicrobial resistance to the recipients. Transfer of high-level resistance to the transconjugants encoded by the blaCTX-M-15 gene downstream the ISEcp1 insertion sequence against 3rd generation cephalosporins, and of low-level resistance against ciprofloxacin, and variable levels of resistance against aminoglycosides encoded by aac(6'-lb-cr gene, were observed in transconjugants. tra encoding transferase genes were detected exclusively in conjugative isolates. Conclusion In conclusion, the frequency of transfer of antimicrobial resistance in non clonal Enterobacteriaceae at the tertiary care center by conjugation was 49%. Conjugation occurred in isolates expressing the tra encoding transferase genes. Multiple conjugative strains harboring the plasmid encoded antimicrobial resistant genes were circulating in

  19. Gentamicin Blocks the ACh-Induced BK Current in Guinea Pig Type II Vestibular Hair Cells by Competing with Ca2+ at the l-Type Calcium Channel

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    Hong Yu

    2014-04-01

    Full Text Available Type II vestibular hair cells (VHCs II contain big-conductance Ca2+-dependent K+ channels (BK and L-type calcium channels. Our previous studies in guinea pig VHCs II indicated that acetylcholine (ACh evoked the BK current by triggering the influx of Ca2+ ions through l-type Ca2+ channels, which was mediated by M2 muscarinic ACh receptor (mAChRs. Aminoglycoside antibiotics, such as gentamicin (GM, are known to have vestibulotoxicity, including damaging effects on the efferent nerve endings on VHCs II. This study used the whole-cell patch clamp technique to determine whether GM affects the vestibular efferent system at postsynaptic M2-mAChRs or the membrane ion channels. We found that GM could block the ACh-induced BK current and that inhibition was reversible, voltage-independent, and dose-dependent with an IC50 value of 36.3 ± 7.8 µM. Increasing the ACh concentration had little influence on GM blocking effect, but increasing the extracellular Ca2+ concentration ([Ca2+]o could antagonize it. Moreover, 50 µM GM potently blocked Ca2+ currents activated by (--Bay-K8644, but did not block BK currents induced by NS1619. These observations indicate that GM most likely blocks the M2 mAChR-mediated response by competing with Ca2+ at the l-type calcium channel. These results provide insights into the vestibulotoxicity of aminoglycoside antibiotics on mammalian VHCs II.

  20. Análisis genómico del resistoma de la cepa de Acinetobacter baumannii ABIBUN 107m multi-resistente y persistente en hospitales colombianos

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    Maria Teresa Reguero

    2014-12-01

    Full Text Available Acinetobacter baumannii is a bacterium causing health care associated infections such as pneumonia, septicemia, meningitis and urinary infections amongst others. It has great capacity to quickly develop and gather a big variety of drug resistance mechanisms. In this research, the genome of strain A. baumannii ABIBUN 107m was analyzed wich forms part of a persistent clon in Colombian hospitals and it’s also resistant to carbapenems (imipenem and meropenem, which are the election antibiotics for treatment of infections caused by this microorganism. The genome was sequenced using high performance technology, assembled and annotated. As a result, we obtained a 3954000 bp genome, with 56 contigs; 4256 genes with average size of 912 bp; 3796 CDS; 2884 were assigned to COG; 57 tRNA and GC percentage of 38,74%. The A. baumannii strain ABIBUN 107m, is resistant to the following antibiotic groups: b-lactams, aminoglycosides, quinolones, tetracycline, sulfonamide and colistin. Genes associated with this resistance profile were found in A. baumannii ABIBUN 107m genome serino b-lactamases (blaADC-38, blaOXA-64, blaOXA-23, blaampC-like, blaamp(H-like, metallo b-lactamase_B; High Molecular Mass penicillin binding proteins, ISAba1 type insertion sequences, mutations of DNA gyrase and topoisomerase IV subunit A (gyrA and parC; aminoglycoside modifying enzymes (aphA-like, aadA-like; choramphenicol acyltransferase (cat and dehydropteroate synthase (sul-1. Genes belonging to five different efflux systems were identified (RND, MATE, MSF, ATP, SMR.

  1. Surveillance of nosocomial infections in Dr. Cipto Mangunkusumo National General Hospital, Jakarta, 1999-2002

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    Djoko Widodo

    2004-06-01

    Full Text Available Nosocomial infection are one of the main problem in hospital which are associated with significant morbidity, mortality and increased economic cost. Surveillance should be attempted regularly to obtain local data of incidence of nosocomial infections, types of infection, pathogen and resistance pattern. We reported the results of nosocomial surveillance in Dr. Cipto Mangunkusumo National General Hospital, Jakarta, in year 1999 to 2002. The data were obtained from surveillance, conducted by Nosocomial Infection Control Committee. Surveillance were performed to patient in risk of nosocomial infections such as underwent surgical procedure, urinary catheter, peripheral or central venous catheter, ventilator and other invasive procedure. Criteria for nosocomial infection which were used, based on technical guidelines of nosocomial infection in Dr. Cipto Mangunkusumo National General Hospital, year 1999; which referred to CDC definition of nosocomial infections. Incidence rate of nosocomial infections in year 1999, 2000, 2001 and 2002 were 1.1, 0.9, 0.6 and 0.4 % respectively. Type of nosocomial infection include catheter related, surgical wound, urinary tract and respiratory tract infections, ranged between 0 to 5.6 %. Gram negative bacteria consist of Pseudomonas sp, Enterobacter aerogenes, Escherichia coli, Proteus mirabilis were the most common nosocomial pathogen. Gram positive bacteria consist of Staphylococcus epidermidis, Staphylococcus aureus and Streptococcus anhemolyticus. Trend of increasing incidence of Gram positive nosocomial infection also showed in our surveillance. Mostly Gram negative bacteria had been resistant to penicillin, co amoxicillin-clavulanic acid and 3rd generation cephalosporin, but still sensitive to 4th generation cephalosporin and aminoglycoside. The Gram positive bacteria were still sensitive to penicillin, co amoxicillin-clavulanic acid, 4th generation cephalosporin and aminoglycoside. (Med J Indones 2004; 13: 107

  2. Extracellular gentamicin reduces the activity of connexin hemichannels and interferes with purinergic Ca2+ signaling in HeLa cells

    Science.gov (United States)

    Figueroa, Vania A.; Retamal, Mauricio A.; Cea, Luis A.; Salas, José D.; Vargas, Aníbal A.; Verdugo, Christian A.; Jara, Oscar; Martínez, Agustín D.; Sáez, Juan C.

    2014-01-01

    Gap junction channels (GJCs) and hemichannels (HCs) are composed of protein subunits termed connexins (Cxs) and are permeable to ions and small molecules. In most organs, GJCs communicate the cytoplasm of adjacent cells, while HCs communicate the intra and extracellular compartments. In this way, both channel types coordinate physiological responses of cell communities. Cx mutations explain several genetic diseases, including about 50% of autosomal recessive non-syndromic hearing loss. However, the possible involvement of Cxs in the etiology of acquired hearing loss remains virtually unknown. Factors that induce post-lingual hearing loss are diverse, exposure to gentamicin an aminoglycoside antibiotic, being the most common. Gentamicin has been proposed to block GJCs, but its effect on HCs remains unknown. In this work, the effect of gentamicin on the functional state of HCs was studied and its effect on GJCs was reevaluated in HeLa cells stably transfected with Cxs. We focused on Cx26 because it is the main Cx expressed in the cochlea of mammals where it participates in purinergic signaling pathways. We found that gentamicin applied extracellularly reduces the activity of HCs, while dye transfer across GJCs was not affected. HCs were also blocked by streptomycin, another aminoglycoside antibiotic. Gentamicin also reduced the adenosine triphosphate release and the HC-dependent oscillations of cytosolic free-Ca2+ signal. Moreover, gentamicin drastically reduced the Cx26 HC-mediated membrane currents in Xenopus laevis oocytes. Therefore, the extracellular gentamicin-induced inhibition of Cx HCs may adversely affect autocrine and paracrine signaling, including the purinergic one, which might partially explain its ototoxic effects. PMID:25237294

  3. Low Prevalence of Carbapenem-Resistant Bacteria in River Water: Resistance Is Mostly Related to Intrinsic Mechanisms.

    Science.gov (United States)

    Tacão, Marta; Correia, António; Henriques, Isabel S

    2015-10-01

    Carbapenems are last-resort antibiotics to handle serious infections caused by multiresistant bacteria. The incidence of resistance to these antibiotics has been increasing and new resistance mechanisms have emerged. The dissemination of carbapenem resistance in the environment has been overlooked. The main goal of this research was to assess the prevalence and diversity of carbapenem-resistant bacteria in riverine ecosystems. The presence of frequently reported carbapenemase-encoding genes was inspected. The proportion of imipenem-resistant bacteria was on average 2.24 CFU/ml. Imipenem-resistant strains (n=110) were identified as Pseudomonas spp., Stenotrophomonas maltophilia, Aeromonas spp., Chromobacterium haemolyticum, Shewanella xiamenensis, and members of Enterobacteriaceae. Carbapenem-resistant bacteria were highly resistant to other beta-lactams such as quinolones, aminoglycosides, chloramphenicol, tetracyclines, and sulfamethoxazole/trimethoprim. Carbapenem resistance was mostly associated with intrinsically resistant bacteria. As intrinsic resistance mechanisms, we have identified the blaCphA gene in 77.3% of Aeromonas spp., blaL1 in all S. maltophilia, and blaOXA-48-like in all S. xiamenensis. As acquired resistance mechanisms, we have detected the blaVIM-2 gene in six Pseudomonas spp. (5.45%). Integrons with gene cassettes encoding resistance to aminoglycosides (aacA and aacC genes), trimethoprim (dfrB1b), and carbapenems (blaVIM-2) were found in Pseudomonas spp. Results suggest that carbapenem resistance dissemination in riverine ecosystems is still at an early stage. Nevertheless, monitoring these aquatic compartments for the presence of resistance genes and its host organisms is essential to outline strategies to minimize resistance dissemination. PMID:26430939

  4. Drug utilization study in the otorhinolaryngology department in a tertiary care hospital

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    S. A. Sridevi

    2013-06-01

    Full Text Available Background: Drug utilization is defined by the World Health Organization (WHO as the marketing, distribution, prescription, and use of drugs in society, with special emphasis on the resulting medical, social, and economic consequences. The aim of this study was to evaluate the pattern of prescription and then drug utilization in outpatient (OPD of the Department of Otolaryngology in a tertiary care teaching hospital. Methods: This was a retrospective study conducted at the A.C.S. medical college and hospital, Chennai for a period of 7 months. All the patients who attended the Ear Nose and Throat (ENT OPD were included. The total number who attended the OPD was 10,249 which include 6,956 new cases and 3313 old cases. Results: The antibacterials commonly used were β Lactams (56%, macrolides (14%, fluoroquinolones (12%, aminoglycosides (8%. Among the penicillin group, the commonest drug prescribed was a combination of amoxicillin and clavulanic acid (27%, in cephalosporins was cefixime + clavulanic acid (19%. Aminoglycosides include gentamycin in refractory cases. Fluoroquinolones include ciprofloxacin and levofloxacin. Others Drugs like antihistamines and mucolytics were prescribed in 27%, anti- ulcer drugs in 36% cases, analgesics in 33% cases and herbal medicines in 4%. The average number of drugs used in each prescription was 3.20. All the drugs were prescribed with brand names. The average cost per prescription per day for OPD patients is 37 Rupees. Conclusions: β Lactams were commonly used antibacterials in the otorhinolaryngology department. [Int J Basic Clin Pharmacol 2013; 2(3.000: 306-310

  5. Simultaneous antibacterial and anticoagulant properties of polypropylene non-woven textiles Elaboration d'un textile polypropylène non-tissé présentant simultanément des propriétés antibactériennes et anticoagulantes

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    Jimenez Maude

    2013-11-01

    Full Text Available The aim of this work was to prepare a non-woven Polypropylene (PP textile functionalized with bioactive molecules to improve simultaneously its anticoagulation and antibacterial properties. The immobilization of either heparin (anticoagulation agent or gentamicin (aminoglycoside antibiotic was already proven to be effective on non-woven PP textiles. This work details how we managed to immobilize both gentamicin and heparin on the textile [1]. The immobilization times were studied in order to determine the best compromise between cytocompatibility, anticoagulant effect and antimicrobial activity. Cetté étude décrit le procédé de fonctionnalisation d'un textile polypropylène (PP non-tissé afin d'améliorer à la fois ses propriétés antibactériennes et anticoagulantes. Dans des précédents travaux, l'immobilisation soit de l'héparine (agent anticoagulant, soit de la gentamicine (agent antibiotique aminoglycoside a déjà été reportée. Des effets respectivement anticoagulants et antibactériens ont été obtenus. Cette étude décrit la faç on d'immobiliser ces deux principes actifs sur un même textile. L'effet des temps d'imprégnation sur les propriétés antibactériennes et anticoagulantes a été étudié afin d'obtenir le meilleur compromis possible en termes de cytocompatibilité, effet anticoagulant et activité antimicrobienne.

  6. High prevalence ofblaCTX-M inEnterobacteriaceae isolates from the Kingdom of Bahrain

    Institute of Scientific and Technical Information of China (English)

    Khalid M Bindayna; Mariam Murtadha

    2011-01-01

    Objective:To determine the molecular epidemiology of extended-spectrum β-lactamase (ESBL) by testing a cohort of clinicalESBL-producing bacterial isolates that were isolated in the Kingdom of Bahrain.Methods:ESBLproducingEnterobacteriaceae isolates (based on phenotypic tests) were collected from Microbiology Laboratory of the Salmaniya Medical Complex, Bahrain between January-June2006. Antibiotic susceptibility to a panel of antibiotics was performed andblaCTX-M genes were detected by multiplexPCR.Results: A total of230 isolates (Escherichia coli,n=180;Klebsiella pneumoniae,n=50) were studied,98% were CTX-M type. ForEscherichia coli isolates,65 (36.1%)harboredCTXM+TEMcombination and68(37.8%) had CTX-M alone. In contrast, forKlebsiella pneumoniae isolates only 5 (10.0%) harbored the CTX-M combination, and none had CTX-M only. The blaCTX-Mgene was found predominantly in urine isolates (n=145/230; 63.0%). Sensitivity to imipenem and nitrofurantoin was100% and 60%, respectively.CTX-M carriage was associated with the resistance to fluoroquinolones, trimethoprim-sulfamethoxazole and aminoglycosides.Conclusions: Our study documentes high prevalence ofCTX-M ESBL type amongEscherichia coliandKlebsiella from the Kingdom of Bahrain. The apparent dissemination of CTX-Mproducers could represent a substantial barrier in the treatment of community-acquired infections. The use of extended-spectrum cephalosporins, quinolones, and aminoglycosides is compromised, leaving carbapenems as the therapeutic option for severe infections caused byESBL producers.

  7. Antimicrobial resistance of Escherichia coli isolates from canine urinary tract infections.

    Science.gov (United States)

    Chang, Shao-Kuang; Lo, Dan-Yuan; Wei, Hen-Wei; Kuo, Hung-Chih

    2015-01-01

    This study determined the antimicrobial resistance profiles of Escherichia coli isolates from dogs with a presumptive diagnosis of urinary tract infection (UTI). Urine samples from 201 dogs with UTI diagnosed through clinical examination and urinalysis were processed for isolation of Escherichia coli. Colonies from pure cultures were identified by biochemical reactions (n=114) and were tested for susceptibility to 18 antimicrobials. The two most frequent antimicrobials showing resistance in Urinary E. coli isolates were oxytetracycline and ampicillin. Among the resistant isolates, 17 resistance patterns were observed, with 12 patterns involving multidrug resistance (MDR). Of the 69 tetracycline-resistant E. coli isolates, tet(B) was the predominant resistance determinant and was detected in 50.9% of the isolates, whereas the remaining 25.5% isolates carried the tet(A) determinant. Most ampicillin and/or amoxicillin-resistant E. coli isolates carried blaTEM-1 genes. Class 1 integrons were prevalent (28.9%) and contained previously described gene cassettes that are implicated primarily in resistance to aminoglycosides and trimethoprim (dfrA1, dfrA17-aadA5). Of the 44 quinolone-resistant E. coli isolates, 38 were resistant to nalidixic acid, and 6 were resistant to nalidixic acid, ciprofloxacin and enrofloxacin. Chromosomal point mutations were found in the GyrA (Ser83Leu) and ParC (Ser80Ile) genes. Furthermore, the aminoglycoside resistance gene aacC2, the chloramphenicol resistant gene cmlA and the florfenicol resistant gene floR were also identified. This study revealed an alarming rate of antimicrobial resistance among E. coli isolates from dogs with UTIs. PMID:25720807

  8. Efficacy of intravenous ciprofloxacin in patients with febrile neutropenia refractory to initial therapy.

    Science.gov (United States)

    Matsuoka, Hitoshi; Tsukamoto, Atsuko; Shirahashi, Akihiko; Koga, Shin; Suzushima, Hitoshi; Shibata, Keisuke; Uozumi, Kimiharu; Yamashita, Kiyoshi; Okamura, Seiichi; Kawano, Fumio; Tamura, Kazuo

    2006-08-01

    We previously reported that monotherapy with carbapenem or cefepime exhibited efficacy equivalent to cefepime plus an aminoglycoside as initial therapy for febrile neutropenia (FN), achieving an adequate response in two-thirds of the patients. However, only one-third of the remaining poor responders to monotherapy became afebrile after an aminoglycoside was added to the initial carbapenem or cefepime. The present study was designed to evaluate the benefit of intravenous ciprofloxacin for neutropenic patients with fever who were refractory to initial therapy given for the first 3 days. Patients with FN--as defined by an axillary temperature >or=37.5 degrees C and a neutrophil count ciprofloxacin 600 mg/day. They were otherwise managed according to the Japanese guidelines for FN. An adequate response was defined as a decline of temperature to ciprofloxacin treatment. Thirty-one patients with FN (seventeen male and fourteen female; mean age 53.1 +/- 14.8 years) were entered in the study. The initial antibiotics were cefepime (2 - 4 g/day) in twenty and carbapenem (1 - 2 g/day) in eleven. Three patients were excluded from analysis, leaving 28 patients for evaluation of efficacy. The response rate was 16/31 patients (51.6%),with four patients judged non-assessable due to adverse effects, protocol violation or early change to other agents. Adverse events occurred in seventeen patients, but all were mild and reversible. Only three patients had adverse events (skin rash, hepatic dysfunction and elevation of alkaline phosphatase in one patient, respectively) considered related to ciprofloxacin. These findings indicate that addition of intravenous ciprofloxacin is effective against FN refractory to initial antibiotic therapy and has acceptable toxicity. PMID:16966275

  9. Microbiological and Epidemiological Features of Clinical Respiratory Isolates of Burkholderia gladioli▿

    Science.gov (United States)

    Segonds, Christine; Clavel-Batut, Patricia; Thouverez, Michelle; Grenet, Dominique; Le Coustumier, Alain; Plésiat, Patrick; Chabanon, Gérard

    2009-01-01

    Burkholderia gladioli, primarily known as a plant pathogen, is involved in human infections, especially in patients with cystic fibrosis (CF). In the present study, the first respiratory isolates recovered from 14 French patients with CF and 4 French patients without CF, identified by 16S rRNA gene analysis, were tested for growth on B. cepacia selective media, for identification by commercial systems, and for their antimicrobial susceptibilities, and were compared by pulsed-field gel electrophoresis (PFGE). Patients' data were collected. All 18 isolates grew on oxidation-fermentation-polymyxin B-bacitracin-lactose medium and Pseudomonas cepacia agar, but only 13 grew on Burkholderia cepacia selective agar. API 20NE strips did not differentiate B. gladioli from B. cepacia, whereas Vitek 2 GN cards correctly identified 15 isolates. All isolates were susceptible to piperacillin, imipenem, aminoglycosides, and ciprofloxacin and were far less resistant to ticarcillin than B. cepacia complex organisms. Fifteen PFGE types were observed among the 18 isolates, but shared types were not identified among epidemiologically related patients. The microbiological follow-up of CF patients showed that colonization was persistent in 3 of 13 documented cases; B. gladioli was isolated from posttransplantation cultures of blood from 1 patient. Among the patients without CF, B. gladioli was associated with intubation (three cases) or bronchiectasis (one case). In summary, the inclusion of B. gladioli in the databases of commercial identification systems should improve the diagnostic capabilities of those systems. In CF patients, this organism is more frequently involved in transient infections than in chronic infections, but it may be responsible for complications posttransplantation; patient-to-patient transmission has not been demonstrated to date. Lastly, B. gladioli appears to be naturally susceptible to aminoglycosides and ciprofloxacin, although resistant isolates may emerge in

  10. Mechanisms of antimicrobial resistance in Gram-negative bacilli.

    Science.gov (United States)

    Ruppé, Étienne; Woerther, Paul-Louis; Barbier, François

    2015-12-01

    The burden of multidrug resistance in Gram-negative bacilli (GNB) now represents a daily issue for the management of antimicrobial therapy in intensive care unit (ICU) patients. In Enterobacteriaceae, the dramatic increase in the rates of resistance to third-generation cephalosporins mainly results from the spread of plasmid-borne extended-spectrum beta-lactamase (ESBL), especially those belonging to the CTX-M family. The efficacy of beta-lactam/beta-lactamase inhibitor associations for severe infections due to ESBL-producing Enterobacteriaceae has not been adequately evaluated in critically ill patients, and carbapenems still stands as the first-line choice in this situation. However, carbapenemase-producing strains have emerged worldwide over the past decade. VIM- and NDM-type metallo-beta-lactamases, OXA-48 and KPC appear as the most successful enzymes and may threaten the efficacy of carbapenems in the near future. ESBL- and carbapenemase-encoding plasmids frequently bear resistance determinants for other antimicrobial classes, including aminoglycosides (aminoglycoside-modifying enzymes or 16S rRNA methylases) and fluoroquinolones (Qnr, AAC(6')-Ib-cr or efflux pumps), a key feature that fosters the spread of multidrug resistance in Enterobacteriaceae. In non-fermenting GNB such as Pseudomonas aeruginosa, Acinetobacter baumannii and Stenotrophomonas maltophilia, multidrug resistance may emerge following the sole occurrence of sequential chromosomal mutations, which may lead to the overproduction of intrinsic beta-lactamases, hyper-expression of efflux pumps, target modifications and permeability alterations. P. aeruginosa and A. baumannii also have the ability to acquire mobile genetic elements encoding resistance determinants, including carbapenemases. Available options for the treatment of ICU-acquired infections due to carbapenem-resistant GNB are currently scarce, and recent reports emphasizing the spread of colistin resistance in environments with high

  11. [Trend in the susceptibility of the most frequent bacterial pathogens isolated at Hospital General La Mancha Centro over 2010-2012 period].

    Science.gov (United States)

    Asencio, María Ángeles; Huertas, María; Carranza, Rafael; Franco, María; Castellanos, Jesús; Barberá, José Ramón; Conde, María del Carmen; Tenías, José María

    2014-12-01

    Introduction. Our objective was to determine the trend of the antimicrobial susceptibility of the most common bacterial pathogens isolated in La Mancha Centro Hospital (MCH) between 2010-2012. Material and methods. Isolates of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa from patients admitted to MCH were studied. These data and their antibiotic susceptibility were obtained from the database OBSERVA (BioMérieux). Results. The percentages of susceptibility for S. aureus were: 50% methicillin-resistant-S. aureus (MRSA) (higher co-resistance to erythromycin and levofloxacin), 46% erythromycin, 73% clindamycin, 45% levofloxacin, 99% rifampin and 100% cotrimoxazole, glycopeptides, linezolid and daptomycin. Increased resistance in ICU was observed (63% MRSA), with 50% of S. aureus (susceptible and methicillin-resistant strains) with vancomycin MIC values ≥ 0.5 mg/L. E. coli susceptibility: 62% amoxicillin-clavulanate, 55% ciprofloxacin, 60% cotrimoxazole, 84% gentamicin and 95% fosfomycin. K. pneumoniae susceptibility: 74% amoxicillin-clavulanate, 71% ciprofloxacin, 78% cotrimoxazole, 94% gentamicin and 87% fosfomycin. The percentage of BLEE strains was 17% and 21% for E. coli and K. pneumoniae, respectively, without detection of resistance to carbapenems. P. aeruginosa susceptibility: 80% ceftazidime and carbapenems, 63% ciprofloxacin and higher than 90% aminoglycosides. A decreasing trend of susceptibility to ceftazidime and carbapenems was observed in ICU and increasing trend to ciprofloxacin. Conclusions. Resistance percentages were higher in ICU than in the rest of the hospital, highlighting 63% of MRSA strains. Our percentage of BLEE and MRSA strains were higher than the Spanish media. Rifampicin and cotrimoxazole maintain good susceptibility to S. aureus, fosfomycin and aminoglycosides to Enterobacteriaceae and carbapenems to P. aeruginosa. PMID:25536430

  12. A hospital outbreak of severe acute respiratory syndrome in Guangzhou,China

    Institute of Scientific and Technical Information of China (English)

    伍卫; 王景峰; 刘品明; 陈为宪; 尹松梅; 江山平; 严励; 詹俊; 陈锡龙; 李建国; 黄子通; 黄洪章

    2003-01-01

    Objective To describe a hospital outbreak of severe acute respiratory syndrome (SARS) and summarize its clinical features and therapeutic approaches.MethodsThe outbreak started with a SARS patient from the community, and a total of 96 people (76 women and 20 men, mean age (29.5±10.3) years, 93.8% of whom were health care workers) who had exposure to this source patient became infected in a short time. Clinical data in this cohort ere collected prospectively as they were identified.Results(1) The incubation period ranged from 1 to 20 (mean: 5.9±3.5) days. The duration of hospitalization was (17.2±8.0) days. (2) The initial temperature was (38.3±0.6)℃, while the highest was (39.2±0.6)℃ (P<0.001), with fever duration of (9.0±4.2) days. (3) Other most common symptoms included fatigue (93.8%), cough (85.4%), mild sputum production (66.7%), chills (55.2%), headache (39.6%), general malaise (35.4%) and myalgia (21.9%). (4) The radiographic changes were predominantly bilateral in the middle or lower lung zones. The number of affected lung fields was 1.2±0.8 on presentation, which increased to 2.9±1.4 after admission (P<0.001). The interval from the eginning of fever to the onset of abnormal chest radiographs was (3.5±2.3) days, which increased in size, extent, and severity to the maximum (6.7±3.5) days later. The time before the lung opacities were basically absorbed was (14.9±7.8) days. (5) Leukopenia was observed In 67.7% of this cohort. The time between the onset of fever and leukopenia was (4.4±2.3) days, with the lowest white blood cell count of (2.80±0.72)×109/L. (6) The lowest arterial oxygen saturation was (94.8±3.1)% with supplementary oxygen. (7) Antibiotical therapies included tetracyclines (91.0%), aminoglycosides (83.3%), quinolones (79.2%); 18.8% of the patients received a combination of tetracyclines and aminoglycosides, while 11.5% received a combination of tetracyclines and quinolones, and

  13. Modifier factors influencing the phenotypic manifestation of the deafness-associated mitochondrial DNA mutations%修饰因子对线粒体DNA突变致聋的影响

    Institute of Scientific and Technical Information of China (English)

    杨爱芬; 郑静; 吕建新; 管敏鑫

    2011-01-01

    Mutations in the mitochondrial DNA have been found to be one of the most important causes of sensorineural hearing loss. In particular, these mutations often occur in the mitochondrial 12S rRNA and tRNA genes. Of these, the homoplasmic A1555G and C1494T mutations in the 12S rRNA have been associated with both aminoglycoside induced and nonsyndromic hearing impairment in many families worldwide. Children carrying the A1555G or C1494T mutation are susceptible to the exposure of ototoxic drugs, thereby inducing or worsening hearing loss. Individuals harboring A1555G or C1494T mutation can also develop hearing loss even in the absence of aminoglycoside exposure. However, matrilineal relatives of intra-families or inter-families carrying the A1555G or C1494T mutation exhibit a wide range of severity,age-at-onset, and audiometric configuration of hearing impairment. These indicate that the A1555G or C1494T mutation is a primary factor underlying the development of deafness but insufficient to produce the clinical phenotype. Thus, other modifier factors, such as aminoglycoside (s), mitochondrial DNA haplotype(s) or nuclear modifier gene(s), play a role in the phenotypic expression of the deafness-associated mitochondrial 12S rRNA A1555G or C1494T mutation. In this review, we summarize the modifier factors for the phenotypic expression of deafness-associated 12S rRNA A1555G and C1494T mutations and propose the molecular pathogenetic mechanism of maternally inherited deafness.%线粒体DNA突变是引起感音神经性耳聋的重要原因之一,这些突变主要位于线粒体12SrRNA和tRNA基因上.其中12S rRNA基因上的同质性A1555G和C1494T突变与氨基糖甙类抗生素造成的耳聋相关.携带这两个突变的个体对耳毒性药物高度敏感,导致临床上常见的"一针致聋"现象.但携带A1555G或C1494T突变的个体在没用药的情况下也能产生非综合征型耳聋,而且同一家系内和不同家系间的母系成员在听力损失

  14. Rastreamento da mutação mitocondrial A1555G em pacientes com deficiência auditiva sensorioneural Screening of the mitochondrial A1555G mutation in patients with sensorineural hearing loss

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    Luciano Pereira Maniglia

    2008-10-01

    Full Text Available A mutação mitocondrial A1555G é a principal alteração associada à surdez ocasionada pelo uso de aminoglicosídeos. OBJETIVO: Investigar a prevalência da mutação A1555G em pacientes com deficiência auditiva sensorioneural com e sem uso de antibióticos aminoglicosídeos. MATERIAL E MÉTODO: Estudo em amostras de 27 pacientes com surdez, como casos, e em 100 neonatos, com audição normal, como grupo controle. O DNA foi extraído de leucócitos de amostras de sangue e "primers" específicos foram utilizados para amplificar o gene do citocromo b e a região que abrange a mutação A1555G do DNA mitocondrial, usando as técnicas da Reação em Cadeia da Polimerase e do Polimorfismo no Comprimento de Fragmentos de Restrição. DESENHO CIENTÍFICO: Estudo de casos em corte transversal. RESULTADOS: A região do gene do citocromo b foi amplificada, sendo confirmada a presença do DNA mitocondrial em todas as 127 amostras do estudo. A mutação A1555G não foi identificada nos 27 pacientes com deficiência auditiva e no grupo controle (100 neonatos. CONCLUSÕES: Os resultados são concordantes com estudos que relatam que a mutação A1555G não é prevalente nas Américas. Há interesse na determinação da real prevalência dessa mutação e na investigação de outras mutações que possam ocasionar deficiência auditiva associada ou não ao uso de aminoglicosídeos na população brasileira.The A1555G mitochondrial mutation is the main alteration associated with aminoglycoside-induced deafness. AIM: to investigate the prevalence of the A1555G mutation in patients sensorineural hearing loss patients with and without aminoglycosides antibiotic use. MATERIAL AND METHOD: a study of 27 cases with deafness as the sample, and 100 neonates with normal hearing as the control group. DNA was extracted from blood leukocyte samples, and specific oligonucleotide primers were designed to amplify the cytochrome b gene and the region which encloses the A1555

  15. Mitochondrial 12S rRNA A1555G mutation associated with nonsyndromic hearing loss in twenty-five Han Chinese pedigrees%25个携带线粒体12S rRNA A1555G 突变的中国汉族非综合征型耳聋家系

    Institute of Scientific and Technical Information of China (English)

    彭光华; 朱翌; 吕建新; 陈波蓓; 管敏鑫; 郑斌娇; 方芳; 伍越; 梁玲芝; 郑静; 南奔宇; 余啸; 唐霄雯

    2013-01-01

    Mitochondrial 12S rRNA A1555AG mutation is one of the important causes of aminoglycoside-induced and nonsyndromic deafness. We report here the cilinical, genetic and molecular characterization of 25 Chinese families carrying the A1555G mutation.Clinical and genetic characterizations of these Chinese families exhibited a wide range of penetrance, severity and age-at-onset of hearing impairment. The average penetrances of deafness were 28.1% and 21.5%, respectively, when aminoglycoside-induced hearing loss was included or excluded. Furthermore, the average age-of-onset for deafness without aminoglycoside exposure ranged from 1 and 15 years old. Their mitochondrial genomes exhibited distinct sets of polymorphisms including 16 novel variants, belonging to ten Eastern Asian haplogroups A, B, D, F, G, M, N and R, respectively. Strikingly, these Chinese families carrying mitochondrial haplogroup B exhibited higher penetrance and expressivity of hearing loss. In addition, 7 known secondary mutations and 21 variants resided at the highly conservative residues may enhance the penetrace of hearing loss in these Chinese families. Moreover, the absence of mutation in GJB2 gene suggested that GJB2 may not be a modifier for the phenotypic expression of the A1555G mutation in these Chinese families. These observations suggested that mitochondrial haplotypes and other modifiers may modulate the variable penetrance and expressivity of deafness among these Chinese families.%线粒体12S rRNA A1555G 突变是引起氨基糖甙类药物诱导的非综合征型耳聋的重要原因之一.文章对 收集的25 个携带A1555G 突变的中国汉族非综合征型耳聋家系进行了临床和分子遗传学评估.结果表明,这 25 个家系的母系成员在耳聋外显率、听力损失严重程度和发病年龄上存在较大差异.当包括和不包括氨基糖 甙类药物使用史时,耳聋的平均外显率分别为28.1%和21.5%,排除氨基糖甙类药物

  16. Rising prevalence of antimicrobial resistance in urinary tract infections during pregnancy: Necessity for exploring newer treatment options

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    Meher Rizvi

    2011-01-01

    Full Text Available Background: Urinary tract infections (UTI are one of the most common medical complications of pregnancy. The emergence of drug resistance and particularly the Extended-spectrum beta-lactamase production by Escherichia coli and methicillin resistance in Staphylococci, limits the choice of antimicrobials. Materials and Methods: Patients in different stages of pregnancy with or without symptoms of urinary tract infection attending the antenatal clinic of obstetrics and gynaecology were screened for significant bacteriuria, by standard loop method on 5% sheep blood agar and teepol lactose agar. Isolates were identified by using standard biochemical tests and antimicrobial susceptibility testing was done using Kirby Bauer disc diffusion method. Results: A total of 4290 (51.2% urine samples from pregnant females showed growth on culture. Prevalence of asymptomatic bacteriuria 3210 (74.8% was higher than symptomatic UTI 1080 (25.2%. Escherichia coli was the most common pathogen accounting for 1800 (41.9% of the urinary isolates. Among the gram-positive cocci, coagulase negative species of Staphylococci 270 (6.4% were the most common pathogen. Significantly high resistance was shown by the gram negative bacilli as well as gram positive cocci to the β-lactam group of antimicrobials, flouroquinolones and aminoglycosides. Most alarming was the presence of ESBL in 846 (47% isolates of Escherichia coli and 344 (36.9% isolates of Klebsiella pneumoniae, along with the presence of methicillin resistance in 41% of Staphylococcus species and high-level aminoglycoside resistance in 45(30% isolates of Enterococcus species. Glycopeptides and carbepenems were the only group of drugs to which all the strains of gram positive cocci and gram negative bacilli were uniformly sensitive, respectively. Conclusions: Regular screening should be done for the presence of symptomatic or asymptomatic bacteriuria in pregnancy and specific guidelines should be issued for testing

  17. Diversity of Plasmids and Antimicrobial Resistance Genes in Multidrug-Resistant Escherichia coli Isolated from Healthy Companion Animals.

    Science.gov (United States)

    Jackson, C R; Davis, J A; Frye, J G; Barrett, J B; Hiott, L M

    2015-09-01

    The presence and transfer of antimicrobial resistance genes from commensal bacteria in companion animals to more pathogenic bacteria may contribute to dissemination of antimicrobial resistance. The purpose of this study was to determine antimicrobial resistance gene content and the presence of genetic elements in antimicrobial resistant Escherichia coli from healthy companion animals. In our previous study, from May to August, 2007, healthy companion animals (155 dogs and 121 cats) from three veterinary clinics in the Athens, GA, USA area were sampled and multidrug-resistant E. coli (n = 36; MDR, resistance to ≥ 2 antimicrobial classes) were obtained. Of the 25 different plasmid replicon types tested by PCR, at least one plasmid replicon type was detected in 94% (34/36) of the MDR E. coli; four isolates contained as many as five different plasmid replicons. Nine replicon types (FIA, FIB, FII, I2, A/C, U, P, I1 and HI2) were identified with FIB, FII, I2 as the most common pattern. The presence of class I integrons (intI) was detected in 61% (22/36) of the isolates with eight isolates containing aminoglycoside- and/or trimethoprim-resistance genes in the variable cassette region of intI. Microarray analysis of a subset of the MDR E. coli (n = 9) identified the presence of genes conferring resistance to aminoglycosides (aac, aad, aph and strA/B), β-lactams (ampC, cmy, tem and vim), chloramphenicol (cat), sulfonamides (sulI and sulII), tetracycline [tet(A), tet(B), tet(C), tet(D) and regulator, tetR] and trimethoprim (dfrA). Antimicrobial resistance to eight antimicrobials (ampicillin, cefoxitin, ceftiofur, amoxicillin/clavulanic acid, streptomycin, gentamicin, sulfisoxazole and trimethoprim-sulfamethoxazole) and five plasmid replicons (FIA, FIB, FII, I1 and I2) were transferred via conjugation. The presence of antimicrobial resistance genes, intI and transferable plasmid replicons indicate that E. coli from companion animals may play an important role in the

  18. 65株不同圈养野生动物源性肠杆科菌的药敏分析%Application of the Antimicrobial Susceptibility Test for Enterobacteriaceae in 65 Species of Captive Wild Animals

    Institute of Scientific and Technical Information of China (English)

    黄淑芳; 胡新波; 王才益; 江志

    2011-01-01

    Using the method of K-B antimicrobial susceptibility test(AST),we analyzed the drug susceptibility of intestinal rod bacteria to 10 kinds of clinical antibiotics including penicillins,cephalosporins,dilute aminoglycoside,quinolones,and sulfonamides.Intestinal rod bacteria were sampled from wild animals held at Hangzhou Zoo.The most effective drugs were the third generation cephalosporin,cefoperazone,and cefotaxime,which eliminated 83.1%of bacteria.Less effective antibiotics included quinolone and aminoglycoside drugs,which eliminated 60%or more of bacteria.Least effective was cefradine,a first generation cephalosporin.Effectiveness of cephradine was 58.5%,while that of ampicillin penicillin was 43.1%,and that of sulfamethoxazole of quinolone sulfa was 21.5%.This research provides a basis for clinical medication of captive wildlife.%采用K-B法药敏试验,分析圈养野生动物肠杆科菌对青霉素类、头孢类、氨基糖甙类、喹诺酮类、磺胺类的10种临床常用抗生素的药敏情况。结果显示:最敏感的是头孢稀类的三代头孢,头孢哌酮和头孢噻肟,其敏感率均为83.1%;较敏感的为喹诺酮类和氨基糖甙类药物,敏感率大于或等于60%;敏感性较差的是一代头孢中的头孢拉定、磺胺类药中的复方新诺明、青霉素类的氨苄青霉素,其敏感性分别为58.5%、43.1%和21.5%,被研究结果为兽医临床用药提供了依据。

  19. Antibiotics in otorhinolaryngology practice

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    Stefan-Mikić Sandra

    2002-01-01

    Full Text Available Introduction This study investigated utilization of antibacterial agents at the Ear, Nose and Throat Department of the Outpatient Service of the Health Center Novi Sad - Liman and at the Ear, Nose and Throat Clinic of the Clinical Center Novi Sad, in the period February - March 2001. Material and methods All antibacterial agents were classified as group J, regarding Anatomic-Therapeutic-Chemical Classification. Data on drug utilization were presented in Defined Daily Doses (DDD. Patients who were under observation were all treated with antibiotics. Results In regard to prescribed treatment in the Ear, Nose and Throat Department of the Outpatient Service of the Health Center Novi Sad - Liman, most outpatients were treated with macrolide antibiotics - in 26.21%; combination of penicillin and beta-lactamase inhibitors in 20.83% and pyranosides in 16.12%. At the Ear, Nose and Throat Clinic of the Clinical Center Novi Sad, macrolides and lincosamines were most frequently used - in 20.46%; cephalosporins in 19.87% and penicillins susceptible to beta-lactamase in 18.85%. It is extremely positive and in agreement with current pharmacotherapeutic principles that in both institutions peroral ampicillins have not been prescribed. Aminoglycosides have been prescribed in less than 1% of patients of the Ear, Nose and Throat Department of the Outpatient Service of the Health Center Novi Sad - Liman, whereas they were much more frequently prescribed at the Ear, Nose and Throat Clinic of the Clinical Center Novi Sad - in 11.25%. Although there is a positive postantibiotic effect in regard to these antibiotics and it is recommended to use them once a day, in both examined institutions aminoglycosides were given twice a day. In regard to bacterial identification it was done in 80.76% of patients of the Ear, Nose and Throat Department of the Outpatient Service of the Health Center Novi Sad - Liman, while in the Ear, Nose and Throat Clinic of the Clinical Center

  20. Antibiotic consumption and healthcare-associated infections caused by multidrug-resistant gram-negative bacilli at a large medical center in Taiwan from 2002 to 2009: implicating the importance of antibiotic stewardship.

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    I-Ling Chen

    Full Text Available BACKGROUND: Better depicting the relationship between antibiotic consumption and evolutionary healthcare-associated infections (HAIs caused by multidrug-resistant Gram-negative bacilli (MDR-GNB may help highlight the importance of antibiotic stewardship. METHODOLOGY/PRINCIPAL FINDINGS: The correlations between antibiotic consumption and MDR-GNB HAIs at a 2,700-bed primary care and tertiary referral center in Taiwan between 2002 and 2009 were assessed. MDR-GNB HAI referred to a HAI caused by MDR-Enterobacteriaceae, MDR-Pseudomonas aeruginosa or MDR-Acinetobacter spp. Consumptions of individual antibiotics and MDR-GNB HAI series were first evaluated for trend over time. When a trend was significant, the presence or absence of associations between the selected clinically meaningful antibiotic resistance and antibiotic consumption was further explored using cross-correlation analyses. Significant major findings included (i increased consumptions of extended-spectrum cephalosporins, carbapenems, aminopenicillins/β-lactamase inhibitors, piperacillin/tazobactam, and fluoroquinolones, (ii decreased consumptions of non-extended-spectrum cephalosporins, natural penicillins, aminopenicillins, ureidopenicillin and aminoglycosides, and (iii decreasing trend in the incidence of the overall HAIs, stable trends in GNB HAIs and MDR-GNB HAIs throughout the study period, and increasing trend in HAIs caused by carbapenem-resistant (CR Acinetobacter spp. since 2006. HAIs due to CR-Acinetobacter spp. was found to positively correlate with the consumptions of carbapenems, extended-spectrum cephalosporins, aminopenicillins/β-lactamase inhibitors, piperacillin/tazobactam and fluoroquinolones, and negatively correlate with the consumptions of non-extended-spectrum cephalosporins, penicillins and aminoglycosides. No significant association was found between the increased use of piperacilllin/tazobactam and increasing HAIs due to CR-Acinetobacter spp. CONCLUSIONS: The