Artykuły w czasopismach na temat „Aminoglycoside antibiotics”
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Stogios, Peter J., Peter Spanogiannopoulos, Elena Evdokimova, Olga Egorova, Tushar Shakya, Nick Todorovic, Alfredo Capretta, Gerard D. Wright i Alexei Savchenko. "Structure-guided optimization of protein kinase inhibitors reverses aminoglycoside antibiotic resistance". Biochemical Journal 454, nr 2 (9.08.2013): 191–200. http://dx.doi.org/10.1042/bj20130317.
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Activity of the aminoglycoside phosphotransferase APH(3′)-Ia leads to resistance to aminoglycoside antibiotics in pathogenic Gram-negative bacteria, and contributes to the clinical obsolescence of this class of antibiotics. One strategy to rescue compromised antibiotics such as aminoglycosides is targeting the enzymes that confer resistance with small molecules. We demonstrated previously that ePK (eukaryotic protein kinase) inhibitors could inhibit APH enzymes, owing to the structural similarity between these two enzyme families. However, limited structural information of enzyme–inhibitor complexes hindered interpretation of the results. In addition, cross-reactivity of compounds between APHs and ePKs represents an obstacle to their use as aminoglycoside adjuvants to rescue aminoglycoside antibiotic activity. In the present study, we structurally and functionally characterize inhibition of APH(3′)-Ia by three diverse chemical scaffolds, anthrapyrazolone, 4-anilinoquinazoline and PP (pyrazolopyrimidine), and reveal distinctions in the binding mode of anthrapyrazolone and PP compounds to APH(3′)-Ia compared with ePKs. Using this observation, we identify PP derivatives that select against ePKs, attenuate APH(3′)-Ia activity and rescue aminoglycoside antibiotic activity against a resistant Escherichia coli strain. The structures described in the present paper and the inhibition studies provide an important opportunity for structure-based design of compounds to target aminoglycoside phosphotransferases for inhibition, potentially overcoming this form of antibiotic resistance.
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Trylska, Joanna, i Marta Kulik. "Interactions of aminoglycoside antibiotics with rRNA". Biochemical Society Transactions 44, nr 4 (15.08.2016): 987–93. http://dx.doi.org/10.1042/bst20160087.
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Aminoglycoside antibiotics are protein synthesis inhibitors applied to treat infections caused mainly by aerobic Gram-negative bacteria. Due to their adverse side effects they are last resort antibiotics typically used to combat pathogens resistant to other drugs. Aminoglycosides target ribosomes. We describe the interactions of aminoglycoside antibiotics containing a 2-deoxystreptamine (2-DOS) ring with 16S rRNA. We review the computational studies, with a focus on molecular dynamics (MD) simulations performed on RNA models mimicking the 2-DOS aminoglycoside binding site in the small ribosomal subunit. We also briefly discuss thermodynamics of interactions of these aminoglycosides with their 16S RNA target.
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Toth, Marta, Hilary Frase, Nuno T. Antunes i Sergei B. Vakulenko. "Novel Aminoglycoside 2″-Phosphotransferase Identified in a Gram-Negative Pathogen". Antimicrobial Agents and Chemotherapy 57, nr 1 (5.11.2012): 452–57. http://dx.doi.org/10.1128/aac.02049-12.
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ABSTRACTAminoglycoside 2″-phosphotransferases are the major aminoglycoside-modifying enzymes in clinical isolates of enterococci and staphylococci. We describe a novel aminoglycoside 2″-phosphotransferase from the Gram-negative pathogenCampylobacter jejuni, which shares 78% amino acid sequence identity with the APH(2″)-Ia domain of the bifunctional aminoglycoside-modifying enzyme aminoglycoside (6′) acetyltransferase-Ie/aminoglycoside 2″-phosphotransferase-Ia or AAC(6′)-Ie/APH(2″)-Ia from Gram-positive cocci, which we called APH(2″)-If. This enzyme confers resistance to the 4,6-disubstituted aminoglycosides kanamycin, tobramycin, dibekacin, gentamicin, and sisomicin, but not to arbekacin, amikacin, isepamicin, or netilmicin, but not to any of the 4,5-disubstituted antibiotics tested. Steady-state kinetic studies demonstrated that GTP, and not ATP, is the preferred cosubstrate for APH(2″)-If. The enzyme phosphorylates the majority of 4,6-disubstituted aminoglycosides with high catalytic efficiencies (kcat/Km= 105to 107M−1s−1), while the catalytic efficiencies against the 4,6-disubstituted antibiotics amikacin and isepamicin are 1 to 2 orders of magnitude lower, due mainly to the low apparent affinities of these substrates for the enzyme. Both 4,5-disubstituted antibiotics and the atypical aminoglycoside neamine are not substrates of APH(2″)-If, but are inhibitors. The antibiotic susceptibility and substrate profiles of APH(2″)-If are very similar to those of the APH(2″)-Ia phosphotransferase domain of the bifunctional AAC(6′)-Ie/APH(2″)-Ia enzyme.
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Li, Zhongyan, Fengqi Sun, Xinmiao Fu i Yajuan Chen. "5-Methylindole kills various bacterial pathogens and potentiates aminoglycoside against methicillin-resistant Staphylococcus aureus". PeerJ 10 (14.09.2022): e14010. http://dx.doi.org/10.7717/peerj.14010.
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Antibiotic resistance of bacterial pathogens has become a severe threat to human health. To counteract antibiotic resistance, it is of significance to discover new antibiotics and also improve the efficacy of existing antibiotics. Here we show that 5-methylindole, a derivative of the interspecies signaling molecule indole, is able to directly kill various Gram-positive pathogens (e.g., Staphylococcus aureus and Enterococcus faecalis) and also Gram-negative ones (e.g., Escherichia coli and Pseudomonas aeruginosa), with 2-methylindole being less potent. Particularly, 5-methylindole can kill methicillin-resistant S. aureus, multidrug-resistant Klebsiella pneumoniae, Mycobacterium tuberculosis, and antibiotic-tolerant S. aureus persisters. Furthermore, 5-methylindole significantly potentiates aminoglycoside antibiotics, but not fluoroquinolones, killing of S. aureus. In addition, 5-iodoindole also potentiates aminoglycosides. Our findings open a new avenue to develop indole derivatives like 5-methylindole as antibacterial agents or adjuvants of aminoglycoside.
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Stefan-Mikic, Sandra, Ana Sabo, Ana Gobor-Fodor i Marija Vasovic. "Aminoglycoside antibiotics and postantibiotic effect". Medical review 55, nr 1-2 (2002): 19–22. http://dx.doi.org/10.2298/mpns0202019s.
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Man has been fighting diseases for centuries. One of the major battles is against microorganisms and diseases they cause. A health education course was organized on prescribing aminoglycoside antibiotics and postantibiotic effect. The aim of the course was to change the prescription habits in our colleagues. The postantibiotic effect of aminoglycoside antibiotics as well as impact of subinhibiting doses on duration of postantibiotic effect requires modification of previous therapeutic protocols. Single daily dose has the same or even greater effect than multiple daily doses. The toxicity of aminoglycosides is not increased and remains the same or smaller in single daily regimens. Results The single daily dose regimen of aminoglycosides has been used in 63.6% of cases in Clinic for Infectious Diseases of the Clinical Center of Novi Sad, 41.2% in Outpatient Health Care Center of Novi Sad "Liman" and this regimen has not been used in General Practice Department, Children's Health Care Department and Ear, Nose and Throat Clinic at all. The twice daily regimen has been used instead. Conclusion Doctors are aware of the postantibiotic effect, but vast majority are still bound to their old habits in regard to prescribing antibiotics. Our educational course failed to achieve its goal.
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Forge, Andrew, i Jochen Schacht. "Aminoglycoside Antibiotics". Audiology and Neuro-Otology 5, nr 1 (2000): 3–22. http://dx.doi.org/10.1159/000013861.
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Caldwell, Shane, i Albert Berghuis. "A catalytic switch uncovered in gentamicin resistance kinase APH(2'')-Ia". Acta Crystallographica Section A Foundations and Advances 70, a1 (5.08.2014): C704. http://dx.doi.org/10.1107/s205327331409295x.
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The APH(2'')-Ia domain of the bifunctional aminoglycoside resistance enzyme AAC(6')-Ie/APH(2'')-Ia confers high-level resistance to aminoglycoside antibiotics. Crystal structures of this kinase domain in complex with GTP analogues and acceptor substrates have uncovered a surprising conformational bistability of the GTP substrate, which may reduce futile hydrolysis of the cofactor by the enzyme. This conformational switch is influenced by the binding of aminoglycosides, and may represent an adaptive feature of the enzyme, improving its evolutionary fitness in bacterial populations. This mechanism combines with a remarkable flexibility observed in the binding of diverse aminoglycoside substrates to make this enzyme a formidable antibiotic resistance machine.
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Henley, Charles M. "Kanamycin Depletes Cochlear Polyamines in the Developing Rat". Otolaryngology–Head and Neck Surgery 110, nr 1 (styczeń 1994): 103–9. http://dx.doi.org/10.1177/019459989411000112.
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Developing mammals are more sensitive to aminoglycoside antibiotics and other ototoxic agents than adults, with maximum sensitivity occurring during the period of anatomic and functional maturation of the cochlea. For the aminoglycoside antibiotics, the hypersensitive period in rats occurs during the second and third postnatal weeks. Toxicity is initially expressed as outer hair cell (OHC) damage in the high-frequency, basal region of the cochlea. Distortion-product otoacoustic emissions (DPOAEs), physiologic measures of OHC function, are particularly sensitive to aminoglycoside exposure during the period of rapid cochlear physiologic development. Toxicity is characterized by increased DPOAE thresholds and decreased amplitudes. The mechanism of developmental sensitivity to aminoglycosides is unknown. A potential biochemical target of aminoglycosides is the ornithine decarboxylase (ODC)-polyamine pathway. ODC activity is elevated in the developing rat cochlea, aminoglycosides inhibit cochlear ODC in developing rats, and α-difluoromethylornithine (a specific ODC inhibitor) impairs development of cochlear function. In the present study we demonstrate an incomplete polyamnine response to aminoglycoside damage, characterized by inhibition of the polyamines spermidine and spermine and accumulation of putrescine in the organ of Corti. Aminoglycoside inhibition of polyamine synthesis may mediate developmental ototoxic hypersensitivity by interfering with developmental and repair processes.
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Fong, Desiree H., i Albert M. Berghuis. "Structural Basis of APH(3′)-IIIa-Mediated Resistance to N1-Substituted Aminoglycoside Antibiotics". Antimicrobial Agents and Chemotherapy 53, nr 7 (11.05.2009): 3049–55. http://dx.doi.org/10.1128/aac.00062-09.
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ABSTRACT Butirosin is unique among the naturally occurring aminoglycosides, having a substituted amino group at position 1 (N1) of the 2-deoxystreptamine ring with an (S)-4-amino-2-hydroxybutyrate (AHB) group. While bacterial resistance to aminoglycosides can be ascribed chiefly to drug inactivation by plasmid-encoded aminoglycoside-modifying enzymes, the presence of an AHB group protects the aminoglycoside from binding to many resistance enzymes, and hence, the antibiotic retains its bactericidal properties. Consequently, several semisynthetic N1-substituted aminoglycosides, such as amikacin, isepamicin, and netilmicin, were developed. Unfortunately, butirosin, amikacin, and isepamicin are not resistant to inactivation by 3′-aminoglycoside O-phosphotransferase type IIIa [APH(3′)-IIIa]. We report here the crystal structure of APH(3′)-IIIa in complex with an ATP analog, AMPPNP [adenosine 5′-(β,γ-imido)triphosphate], and butirosin A to 2.4-Å resolution. The structure shows that butirosin A binds to the enzyme in a manner analogous to other 4,5-disubstituted aminoglycosides, and the flexible antibiotic-binding loop is key to the accommodation of structurally diverse substrates. Based on the crystal structure, we have also constructed a model of APH(3′)-IIIa in complex with amikacin, a commonly used semisynthetic N1-substituted 4,6-disubstituted aminoglycoside. Together, these results suggest a strategy to further derivatize the AHB group in order to generate new aminoglycoside derivatives that can elude inactivation by resistance enzymes while maintaining their ability to bind to the ribosomal A site.
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Carvalho, André, Didier Mazel i Zeynep Baharoglu. "Deficiency in cytosine DNA methylation leads to high chaperonin expression and tolerance to aminoglycosides in Vibrio cholerae". PLOS Genetics 17, nr 10 (20.10.2021): e1009748. http://dx.doi.org/10.1371/journal.pgen.1009748.
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Antibiotic resistance has become a major global issue. Understanding the molecular mechanisms underlying microbial adaptation to antibiotics is of keen importance to fight Antimicrobial Resistance (AMR). Aminoglycosides are a class of antibiotics that target the small subunit of the bacterial ribosome, disrupting translational fidelity and increasing the levels of misfolded proteins in the cell. In this work, we investigated the role of VchM, a DNA methyltransferase, in the response of the human pathogen Vibrio cholerae to aminoglycosides. VchM is a V. cholerae specific orphan m5C DNA methyltransferase that generates cytosine methylation at 5’-RCCGGY-3’ motifs. We show that deletion of vchM, although causing a growth defect in absence of stress, allows V. cholerae cells to cope with aminoglycoside stress at both sub-lethal and lethal concentrations of these antibiotics. Through transcriptomic and genetic approaches, we show that groESL-2 (a specific set of chaperonin-encoding genes located on the second chromosome of V. cholerae), are upregulated in cells lacking vchM and are needed for the tolerance of vchM mutant to lethal aminoglycoside treatment, likely by fighting aminoglycoside-induced misfolded proteins. Interestingly, preventing VchM methylation of the four RCCGGY sites located in groESL-2 region, leads to a higher expression of these genes in WT cells, showing that the expression of these chaperonins is modulated in V. cholerae by DNA methylation.
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Zieliński, Michał, Jonathan Blanchet, Sophia Hailemariam i Albert M. Berghuis. "Structural elucidation of substrate-bound aminoglycoside acetyltransferase (3)-IIIa". PLOS ONE 17, nr 8 (3.08.2022): e0269684. http://dx.doi.org/10.1371/journal.pone.0269684.
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Canonical aminoglycosides are a large group of antibiotics, where the part of chemical diversity stems from the substitution of the neamine ring system on positions 5 and 6. Certain aminoglycoside modifying enzymes can modify a broad range of 4,5- and 4,6-disubstituted aminoglycosides, with some as many as 15. This study presents the structural and kinetic results describing a promiscuous aminoglycoside acetyltransferase AAC(3)-IIIa. This enzyme has been crystallized in ternary complex with coenzyme A and 4,5- and 4,6-disubstituted aminoglycosides. We have followed up this work with kinetic characterization utilizing a panel of diverse aminoglycosides, including a next-generation aminoglycoside, plazomicin. Lastly, we observed an alternative binding mode of gentamicin in the aminoglycoside binding site, which was proven to be a crystallographic artifact based on mutagenesis.
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Childs-Kean, Lindsey M., Kristy M. Shaeer, Sheeba Varghese Gupta i Jonathan C. Cho. "Aminoglycoside Allergic Reactions". Pharmacy 7, nr 3 (29.08.2019): 124. http://dx.doi.org/10.3390/pharmacy7030124.
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Aminoglycosides are antimicrobial agents that are primarily used for infections caused by Gram-negative pathogens. The purpose of this article is to review the allergic reactions reported in the published literature to aminoglycoside antibiotics. A thorough PubMed search was conducted and excluded non-allergic adverse reactions to aminoglycosides. Allergic reactions to aminoglycosides occur infrequently, but can include cutaneous reactions as well as systemic reactions, including anaphylaxis. Of the evaluated aminoglycosides, gentamicin had the most reported allergic reactions, including the most reports of anaphylaxis, followed by tobramycin, and then amikacin. Most reports of allergic reactions occurred in patients who had a prior exposure to some dosage form of an aminoglycoside. Cross-reactivity among aminoglycosides is common and occurs due to the similarities in their chemical structures. Desensitization protocols to tobramycin have been described in the literature.
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Wassil, Sarah K., Kristie M. Fox i James W. White. "Once Daily Dosing of Aminoglycosides in Pediatric Cystic Fibrosis Patients: A Review of the Literature". Journal of Pediatric Pharmacology and Therapeutics 13, nr 2 (1.01.2008): 68–75. http://dx.doi.org/10.5863/1551-6776-13.2.68.
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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 the dosing interval when concentrations of the drug may be undetectable. This makes the use of once daily dosing of these antibiotics in patients with cystic fibrosis controversial. Although aminoglycosides exhibit a post antibiotic effect, the duration of this effect is unknown in humans; therefore, the development of resistance to the aminoglycoside is a concern. This manuscript will review the organisms most commonly associated with a pulmonary exacerbation of cystic fibrosis, the properties of the aminoglycoside that make once daily dosing feasible, the concept of once daily dosing in those with cystic fibrosis and the current literature regarding efficacy, monitoring, toxicity and concerns of resistance with once daily dosing in this population.
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Jiang, Zheng, Junwei Wei, Yunxiang Liang, Nan Peng i Yingjun Li. "Aminoglycoside Antibiotics Inhibit Mycobacteriophage Infection". Antibiotics 9, nr 10 (19.10.2020): 714. http://dx.doi.org/10.3390/antibiotics9100714.
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Antibiotic resistance is becoming the biggest threat to global health. At the same time, phage therapy is witnessing a return of interest. The therapeutic use of bacteriophages that infect and kill bacteria is a suitable strategy to combat antibiotic resistance. Furthermore, bacteriophages are increasingly used in combination with standard antibiotics against drug-resistant pathogens. Interestingly, we found that the engineered mycobacteriophage phAE159 and natural phage D29 cannot infect the Mycobacterium tuberculosis in the presence of kanamycin, hygromycin or streptomycin, but the phage infection was not affected in the presence of spectinomycin. Based on a series of studies and structural analysis of the above four aminoglycoside antibiotics, it could be speculated that the amino sugar group of aminoglycoside might selectively inhibit mycobacteriophage DNA replication. Our discovery that broad-spectrum antibiotics inhibit phage infection is of great value. This study will provide guidance for people to combine phage and antibiotics to treat M. tuberculosis.
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Toth, Marta, Hilary Frase, Joseph W. Chow, Clyde Smith i Sergei B. Vakulenko. "Mutant APH(2″)-IIa Enzymes with Increased Activity against Amikacin and Isepamicin". Antimicrobial Agents and Chemotherapy 54, nr 4 (9.02.2010): 1590–95. http://dx.doi.org/10.1128/aac.01444-09.
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ABSTRACT Directed evolution by random PCR mutagenesis of the gene for the aminoglycoside 2″-IIa phosphotransferase generated R92H/D268N and N196D/D268N mutant enzymes, resulting in elevated levels of resistance to amikacin and isepamicin but not to other aminoglycoside antibiotics. Increases in the activities of the mutant phosphotransferases for isepamicin are the result of decreases in Km values, while improved catalytic efficiency for amikacin is the result of both a decrease in Km values and an increase in turnover of the antibiotic. Enzymes with R92H, D268N, and D268N single amino acid substitutions did not result in elevated MICs for aminoglycosides.
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Ngo, David, Angel J. Magaña, Tung Tran, Jan Sklenicka, Kimberly Phan, Brian Eykholt, Verónica Jimenez, María S. Ramirez i Marcelo E. Tolmasky. "Inhibition of Enzymatic Acetylation-Mediated Resistance to Plazomicin by Silver Ions". Pharmaceuticals 16, nr 2 (3.02.2023): 236. http://dx.doi.org/10.3390/ph16020236.
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Plazomicin is a recent U.S. Food and Drug Administration (FDA)-approved semisynthetic aminoglycoside. Its structure consists of a sisomicin scaffold modified by adding a 2(S)-hydroxy aminobutyryl group at the N1 position and a hydroxyethyl substituent at the 6′ position. These substitutions produced a molecule refractory to most aminoglycoside-modifying enzymes. The main enzyme within this group that recognizes plazomicin as substrate is the aminoglycoside 2′-N-acetyltransferase type Ia [AAC(2′)-Ia], which reduces the antibiotic’s potency. Designing formulations that combine an antimicrobial with an inhibitor of resistance is a recognized strategy to extend the useful life of existing antibiotics. We have recently found that several metal ions inhibit the enzymatic inactivation of numerous aminoglycosides mediated by the aminoglycoside 6′-N-acetyltransferase type Ib [AAC(6′)-Ib]. In particular, Ag+, which also enhances the effect of aminoglycosides by other mechanisms, is very effective in interfering with AAC(6′)-Ib-mediated resistance to amikacin. Here we report that silver acetate is a potent inhibitor of AAC(2′)-Ia-mediated acetylation of plazomicin in vitro, and it reduces resistance levels of Escherichia coli carrying aac(2′)-Ia. The resistance reversion assays produced equivalent results when the structural gene was expressed under the control of the natural or the blaTEM-1 promoters. The antibiotic effect of plazomicin in combination with silver was bactericidal, and the mix did not show significant toxicity to human embryonic kidney 293 (HEK293) cells.
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Yan, Ribai, Xiaonan Li, Yuheng Liu i Xinshan Ye. "Design, Synthesis, and Bioassay of 2′-Modified Kanamycin A". Molecules 27, nr 21 (2.11.2022): 7482. http://dx.doi.org/10.3390/molecules27217482.
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Chemical modification of old drugs is an important way to obtain new ones, and it has been widely used in developing new aminoglycoside antibiotics. However, many of the previous modifying strategies seem arbitrary for their lack of support from structural biological detail. In this paper, based on the structural information of aminoglycoside and its drug target, we firstly analyzed the reason that some 2′-N-acetylated products of aminoglycosides caused by aminoglycoside-modifying enzyme AAC(2′) can partially retain activity, and then we designed, synthesized, and evaluated a series of 2′-modified kanamycin A derivatives. Bioassay results showed our modifying strategy was feasible. Our study provided valuable structure–activity relationship information, which would help researchers to develop new aminoglycoside antibiotics more effectively.
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Vetting, M., S. L. Roderick, S. Hegde, S. Magnet i J. S. Blanchard. "What can structure tell us about in vivo function? The case of aminoglycoside-resistance genes". Biochemical Society Transactions 31, nr 3 (1.06.2003): 520–22. http://dx.doi.org/10.1042/bst0310520.
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Resistance to antibiotics used in the treatment of bacterial infections is an expanding clinical problem. Aminoglycosides, one of the oldest classes of natural product antibiotics, exert their bactericidal effect as the result of inhibiting bacterial protein synthesis by binding to the acceptor site of the 30 S ribosomal subunit. The most common mechanism of clinical resistance to aminoglycosides results from the expression of enzymes that covalently modify the aminoglycoside. We will discuss the enzymology and structure of two representative chromosomally encoded aminoglycoside N-acetyltransferases, Mycobacterium tuberculosis AAC(2´)-Ic and Salmonella enterica AAC(6´)-Iy, and speculate about their possible physiological function and substrates.
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Mikolasch, Annett, Ulrike Lindequist, Sabine Witt i Veronika Hahn. "Laccase-Catalyzed Derivatization of Aminoglycoside Antibiotics and Glucosamine". Microorganisms 10, nr 3 (15.03.2022): 626. http://dx.doi.org/10.3390/microorganisms10030626.
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The increasing demand for new and effective antibiotics requires intelligent strategies to obtain a wide range of potential candidates. Laccase-catalyzed reactions have been successfully applied to synthesize new β-lactam antibiotics and other antibiotics. In this work, laccases from three different origins were used to produce new aminoglycoside antibiotics. Kanamycin, tobramycin and gentamicin were coupled with the laccase substrate 2,5-dihydroxy-N-(2-hydroxyethyl)-benzamide. The products were isolated, structurally characterized and tested in vitro for antibacterial activity against various strains of Staphylococci, including multidrug-resistant strains. The cytotoxicity of these products was tested using FL cells. The coupling products showed comparable and, in some cases, better antibacterial activity than the parent antibiotics in the agar diffusion assay, and they were not cytotoxic. The products protected mice against infection with Staphylococcus aureus, which was lethal to the control animals. The results underline the great potential of laccases in obtaining new biologically active compounds, in this case new antibiotic candidates from the class of aminoglycosides.
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McKay, G. A., J. Roestamadji, S. Mobashery i G. D. Wright. "Recognition of aminoglycoside antibiotics by enterococcal-staphylococcal aminoglycoside 3'-phosphotransferase type IIIa: role of substrate amino groups." Antimicrobial Agents and Chemotherapy 40, nr 11 (listopad 1996): 2648–50. http://dx.doi.org/10.1128/aac.40.11.2648.
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The interactions of the aminoglycoside 3'-phosphotransferase IIIa with aminoglycoside antibiotics lacking specific amino groups were examined by steady-state kinetic analyses. The results demonstrate that an amino group on C-1 and either an amino or a hydroxyl group at the 2' and 6' positions are important for detoxification of aminoglycosides by this enzyme.
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Liscovitch, M., V. Chalifa, M. Danin i Y. Eli. "Inhibition of neural phospholipase D activity by aminoglycoside antibiotics". Biochemical Journal 279, nr 1 (1.10.1991): 319–21. http://dx.doi.org/10.1042/bj2790319.
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The effects of aminoglycoside antibiotics on phospholipase D (PLD) activity were investigated in permeabilized NG108-15 cells and in isolated rat brain membranes. Neomycin inhibited guanosine 5′-[gamma-thio]triphosphate-stimulated PLD activity in digitonin-permeabilized NG108-15 cells in a concentration-dependent manner (50% inhibition at 100 microM). Neomycin similarly inhibited PLD activity present in rat brain membranes and assayed in vitro with [3H]phosphatidylcholine as substrate (50% inhibition at 65 microM). Other aminoglycosides tested (kanamycin, geneticin and streptomycin) were nearly equipotent inhibitors of rat brain PLD. These results indicate that aminoglycoside antibiotics inhibit phosphatidylcholine-PLD activity with comparable and sometimes greater potency than their well known inhibition of phosphoinositide-phospholipase C. The possibility that PLD inhibition could mediate some of the toxic side effects of aminoglycosides is suggested.
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Kaushik, Karishma S., Nalin Ratnayeke, Parag Katira i Vernita D. Gordon. "The spatial profiles and metabolic capabilities of microbial populations impact the growth of antibiotic-resistant mutants". Journal of The Royal Society Interface 12, nr 107 (czerwiec 2015): 20150018. http://dx.doi.org/10.1098/rsif.2015.0018.
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Antibiotic resistance adversely affects clinical and public health on a global scale. Using the opportunistic human pathogen Pseudomonas aeruginosa , we show that increasing the number density of bacteria, on agar containing aminoglycoside antibiotics, can non-monotonically impact the survival of antibiotic-resistant mutants. Notably, at high cell densities, mutant survival is inhibited. A wide range of bacterial species can inhibit antibiotic-resistant mutants. Inhibition results from the metabolic breakdown of amino acids, which results in alkaline by-products. The consequent increase in pH acts in conjunction with aminoglycosides to mediate inhibition. Our work raises the possibility that the manipulation of microbial population structure and nutrient environment in conjunction with existing antibiotics could provide therapeutic approaches to combat antibiotic resistance.
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Isoherranen, Nina, i Stefan Soback. "Chromatographic Methods for Analysis of Aminoglycoside Antibiotics". Journal of AOAC INTERNATIONAL 82, nr 5 (1.09.1999): 1017–45. http://dx.doi.org/10.1093/jaoac/82.5.1017.
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Abstract Aminoglycosides are antimicrobial agents used frequently in treatment of human and animal diseases caused by aerobic, gram-negative bacteria. Because of the toxicity of these compounds, considerable effort has been attributed to analysis of aminoglycoside content in drug preparations, in serum and urine specimen in therapeutic drug monitoring, and in edible animal tissues in residue control. The present review emphasizes the analytical problems associated with aminoglycoside analysis. Screening methods based on microbiological and immunological procedures were briefly discussed. Gas chromatography and especially high-performance liquid chromatography appeared the most widely used chemical methods for the analysis of these compounds. Due to lack of volatility, chromophore, and hydrophility of aminoglycosides, most methods applied derivatization for enhancement of their chromatographic characteristics. The applicability and advantages of the various derivatization procedures were discussed in detail. A wide variety of detection methods, including mass spectrometry have been used. Packed column separation was generally used for gas chromatographic separation. In liquid chromatography, reversed phase, ion pair, ion exchange, and normal phase separation has been employed. Mass spectrometry, as a detection method, was discussed in detail. Extraction procedures from body fluids and tissues were emphasized. The performance and the operational conditions of the methods were described and detailed information of the data was provided also in table format.
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Dozzo, Paola, i Heinz E. Moser. "New aminoglycoside antibiotics". Expert Opinion on Therapeutic Patents 20, nr 10 (30.07.2010): 1321–41. http://dx.doi.org/10.1517/13543776.2010.506189.
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Farook, Saika, Md Shariful Alam Jilani, Alpona Akhter i J. Ashraful Haq. "Melioidosis by aminoglycoside susceptible Burkholderia pseudomallei: First case in Bangladesh". IMC Journal of Medical Science 14, nr 2 (5.04.2021): 55–59. http://dx.doi.org/10.3329/imcjms.v14i2.52830.
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Burkholderia pseudomallei is the etiological agent of melioidosis. It is a gram-negative bacillus present in environment and intrinsically resistant to many antibiotics including aminoglycosides. However, recently aminoglycoside susceptible B. pseudomallei has been isolated from melioidosis cases and reported from some countries of the world. But, such aminoglycoside susceptible B. pseudomallei has never been detected in Bangladesh either from melioidosis cases or from environment. All the B. pseudomallei isolated so far in Bangladesh were resistant to gentamicin and other aminoglycosides. Here, we describe a disseminated case of melioidosis caused by aminoglycoside susceptible B. pseudomallei in a 55 years old Bengali male patient. This is the first case of melioidosis due to aminoglycoside susceptible B. pseudomallei in Bangladesh.
Ibrahim Med. Coll. J. 2020; 14(2): 55-59
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Ida, Takashi, Ryoichi Okamoto, Masato Nonoyama, Kazuhiko Irinoda, Mizuyo Kurazono i Matsuhisa Inoue. "Antagonism between Aminoglycosides and β-Lactams in a Methicillin-Resistant Staphylococcus aureus Isolate Involves Induction of an Aminoglycoside-Modifying Enzyme". Antimicrobial Agents and Chemotherapy 46, nr 5 (maj 2002): 1516–21. http://dx.doi.org/10.1128/aac.46.5.1516-1521.2002.
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ABSTRACT We encountered three clinical isolates of methicillin-resistant Staphylococcus aureus which were susceptible to netilmicin and arbekacin in the absence of β-lactam antibiotics but which were resistant to them in the presence of β-lactam antibiotics. One of these strains, KU5801, was used to further investigate the antagonism between aminoglycosides and β-lactam antibiotics. β-Lactam antibiotics induced bacterial synthesis of aminoglycoside-6′-N-acetyltransferase and 2"-O-phosphotransferase [AAC(6′)-APH(2")] in association with decreased antimicrobial activities of aminoglycosides. A 14.4-kb EcoRI fragment that included the genes that control for β-lactam-inducible aminoglycoside resistance was cloned from a 31-kb conjugative plasmid present in KU5801. Restriction fragment mapping and PCR analysis suggested that a Tn4001-like element containing a gene encoding AAC(6′)-APH(2") was located downstream from a truncated blaZ gene. The DNA sequence between blaR1 and a Tn4001-like element was determined. The Tn4001-IS257 hybrid structure was cointegrated into the blaZ gene, and the typical sequences for the termination of transcription were not found between these regions. We deduced that antagonism of aminoglycosides by β-lactam antibiotics in isolate KU5801 involved transcription of the aac(6′)-Ie-aph(2")-Ia gene under the influence of the system regulating penicillinase production.
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Plattner, Michel, Marina Gysin, Klara Haldimann, Katja Becker i Sven N. Hobbie. "Epidemiologic, Phenotypic, and Structural Characterization of Aminoglycoside-Resistance Gene aac(3)-IV". International Journal of Molecular Sciences 21, nr 17 (25.08.2020): 6133. http://dx.doi.org/10.3390/ijms21176133.
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Aminoglycoside antibiotics are powerful bactericidal therapeutics that are often used in the treatment of critical Gram-negative systemic infections. The emergence and global spread of antibiotic resistance, however, has compromised the clinical utility of aminoglycosides to an extent similar to that found for all other antibiotic-drug classes. Apramycin, a drug candidate currently in clinical development, was suggested as a next-generation aminoglycoside antibiotic with minimal cross-resistance to all other standard-of-care aminoglycosides. Here, we analyzed 591,140 pathogen genomes deposited in the NCBI National Database of Antibiotic Resistant Organisms (NDARO) for annotations of apramycin-resistance genes, and compared them to the genotypic prevalence of carbapenem resistance and 16S-rRNA methyltransferase (RMTase) genes. The 3-N-acetyltransferase gene aac(3)-IV was found to be the only apramycin-resistance gene of clinical relevance, at an average prevalence of 0.7%, which was four-fold lower than that of RMTase genes. In the important subpopulation of carbapenemase-positive isolates, aac(3)-IV was nine-fold less prevalent than RMTase genes. The phenotypic profiling of selected clinical isolates and recombinant strains expressing the aac(3)-IV gene confirmed resistance to not only apramycin, but also gentamicin, tobramycin, and paromomycin. Probing the structure–activity relationship of such substrate promiscuity by site-directed mutagenesis of the aminoglycoside-binding pocket in the acetyltransferase AAC(3)-IV revealed the molecular contacts to His124, Glu185, and Asp187 to be equally critical in binding to apramycin and gentamicin, whereas Asp67 was found to be a discriminating contact. Our findings suggest that aminoglycoside cross-resistance to apramycin in clinical isolates is limited to the substrate promiscuity of a single gene, rendering apramycin best-in-class for the coverage of carbapenem- and aminoglycoside-resistant bacterial infections.
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Recht, Michael I., i Joseph D. Puglisi. "Aminoglycoside Resistance with Homogeneous and Heterogeneous Populations of Antibiotic-Resistant Ribosomes". Antimicrobial Agents and Chemotherapy 45, nr 9 (1.09.2001): 2414–19. http://dx.doi.org/10.1128/aac.45.9.2414-2419.2001.
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ABSTRACT Aminoglycosides bind to rRNA in the small subunit of the bacterial ribosome. Mutations in the decoding region of 16S rRNA confer resistance to specific subsets of aminoglycoside antibiotics. The two major classes of 2-deoxystreptamine aminoglycosides are the 4,5- and the 4,6-disubstituted antibiotics. Antibiotics of the 4,5-disubstituted class include neomycin, paromomycin, and ribostamycin. Gentamicins and kanamycins belong to the 4,6-disubstituted class of aminoglycosides. Structural studies indicated the potential importance of position 1406 (Escherichia coli numbering) in the binding of ring III of the 4,6-disubstituted class of aminoglycosides to 16S rRNA. We have introduced a U1406-to-A mutation in a plasmid-encoded copy of E. coli 16S rRNA which has been expressed either in a mixture with wild-type ribosomes or in a strain in which all rRNA is transcribed from the plasmid-encoded rrn operon. High-level resistance to many of the 4,6-disubstituted aminoglycosides is observed only when all the rRNA contains the U1406-to-A mutation. In contrast to the partial dominance of resistance observed with other mutations in the decoding region, there is a dominance of sensitivity with the 1406A mutation. Chemical footprinting experiments indicate that resistance arises from a reduced affinity of the antibiotic for the rRNA target. These results demonstrate that although position 1406 is an important determinant in the binding and action of the 4,6-disubstituted aminoglycosides, other rRNA mutations that perturb the binding of ring I of both classes of 2-deoxystreptamine aminoglycosides confer higher levels of resistance as well as a partial dominance of resistance.
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Ezraty, Benjamin, Alexandra Vergnes, Manuel Banzhaf, Yohann Duverger, Allison Huguenot, Ana Rita Brochado, Shu-Yi Su i in. "Fe-S Cluster Biosynthesis Controls Uptake of Aminoglycosides in a ROS-Less Death Pathway". Science 340, nr 6140 (27.06.2013): 1583–87. http://dx.doi.org/10.1126/science.1238328.
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All bactericidal antibiotics were recently proposed to kill by inducing reactive oxygen species (ROS) production, causing destabilization of iron-sulfur (Fe-S) clusters and generating Fenton chemistry. We find that the ROS response is dispensable upon treatment with bactericidal antibiotics. Furthermore, we demonstrate that Fe-S clusters are required for killing only by aminoglycosides. In contrast to cells, using the major Fe-S cluster biosynthesis machinery, ISC, cells using the alternative machinery, SUF, cannot efficiently mature respiratory complexes I and II, resulting in impendence of the proton motive force (PMF), which is required for bactericidal aminoglycoside uptake. Similarly, during iron limitation, cells become intrinsically resistant to aminoglycosides by switching from ISC to SUF and down-regulating both respiratory complexes. We conclude that Fe-S proteins promote aminoglycoside killing by enabling their uptake.
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Carvalho, André, Evelyne Krin, Chloé Korlowski, Didier Mazel i Zeynep Baharoglu. "Interplay between Sublethal Aminoglycosides and Quorum Sensing: Consequences on Survival in V. cholerae". Cells 10, nr 11 (18.11.2021): 3227. http://dx.doi.org/10.3390/cells10113227.
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Antibiotics are well known drugs which, when present above certain concentrations, are able to inhibit the growth of certain bacteria. However, a growing body of evidence shows that even when present at lower doses (subMIC, for sub-minimal inhibitory concentration), unable to inhibit or affect microbial growth, antibiotics work as signaling molecules, affect gene expression and trigger important bacterial stress responses. However, how subMIC antibiotic signaling interplays with other well-known signaling networks in bacteria (and the consequences of such interplay) is not well understood. In this work, through transcriptomic and genetic approaches, we have explored how quorum-sensing (QS) proficiency of V. cholerae affects this pathogen’s response to subMIC doses of the aminoglycoside tobramycin (TOB). We show that the transcriptomic signature of V. cholerae in response to subMIC TOB depends highly on the presence of QS master regulator HapR. In parallel, we show that subMIC doses of TOB are able to negatively interfere with the AI-2/LuxS QS network of V. cholerae, which seems critical for survival to aminoglycoside treatment and TOB-mediated induction of SOS response in this species. This interplay between QS and aminoglycosides suggests that targeting QS signaling may be a strategy to enhance aminoglycoside efficacy in V. cholerae.
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Bulitta, Jürgen B., Neang S. Ly, Cornelia B. Landersdorfer, Nicholin A. Wanigaratne, Tony Velkov, Rajbharan Yadav, Antonio Oliver i in. "Two Mechanisms of Killing of Pseudomonas aeruginosa by Tobramycin Assessed at Multiple Inocula via Mechanism-Based Modeling". Antimicrobial Agents and Chemotherapy 59, nr 4 (2.02.2015): 2315–27. http://dx.doi.org/10.1128/aac.04099-14.
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ABSTRACTBacterial resistance is among the most serious threats to human health globally, and many bacterial isolates have emerged that are resistant to all antibiotics in monotherapy. Aminoglycosides are often used in combination therapies against severe infections by multidrug-resistant bacteria. However, models quantifying different antibacterial effects of aminoglycosides are lacking. While the mode of aminoglycoside action on protein synthesis has often been studied, their disruptive action on the outer membrane of Gram-negative bacteria remains poorly characterized. Here, we developed a novel quantitative model for these two mechanisms of aminoglycoside action, phenotypic tolerance at high bacterial densities, and adaptive bacterial resistance in response to an aminoglycoside (tobramycin) against threePseudomonas aeruginosastrains. At low-intermediate tobramycin concentrations (<4 mg/liter), bacterial killing due to the effect on protein synthesis was most important, whereas disruption of the outer membrane was the predominant killing mechanism at higher tobramycin concentrations (≥8 mg/liter). The extent of killing was comparable across all inocula; however, the rate of bacterial killing and growth was substantially lower at the 108.9CFU/ml inoculum than that at the lower inocula. At 1 to 4 mg/liter tobramycin for strain PAO1-RH, there was a 0.5- to 6-h lag time of killing that was modeled via the time to synthesize hypothetical lethal protein(s). Disruption of the outer bacterial membrane by tobramycin may be critical to enhance the target site penetration of antibiotics used in synergistic combinations with aminoglycosides and thereby combat multidrug-resistant bacteria. The two mechanisms of aminoglycoside action and the new quantitative model hold great promise to rationally design novel, synergistic aminoglycoside combination dosage regimens.
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Wargo, Kurt A., i Jonathan D. Edwards. "Aminoglycoside-Induced Nephrotoxicity". Journal of Pharmacy Practice 27, nr 6 (7.09.2014): 573–77. http://dx.doi.org/10.1177/0897190014546836.
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Aminoglycosides are among the oldest antibiotics available to treat serious infections caused by primarily, Gram-negative bacteria. The most commonly utilized parenteral agents in this class include gentamicin, tobramycin and amikacin. Aminoglycosides are concentration-dependent, bactericidal agents that undergo active transport into the cell where they inhibit protein synthesis on the 30S subunit of the bacterial ribosome. As the use of aminoglycosides became more widespread, the toxic effects of these agents, most notably ototoxicity and nephrotoxicity, became more apparent. When other, safer, antimicrobial agents became available, the use of aminoglycosides sharply declined. The development of multi-drug resistance among bacteria has now lead clinicians to reexamine the role of the aminoglycosides in the treatment of serious infections. This review will revisit the mechanism and risk factors for the development of aminoglycoside-induced nephrotoxicity, as well as strategies to prevent patients from developing nephrotoxicity.
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Kolesnyk, M., K. Zakon i V. Dudarenko. "PHARMACOKINETICS AND PHARMACODYNAMICS OF ANTIMICROBIAL AGENTS IN PATIENTS WITH IMPAIRED RENAL FUNCTION: AMINOGLYCOSIDES". Ukrainian Journal of Nephrology and Dialysis, nr 3(39) (12.12.2017): 57–68. http://dx.doi.org/10.31450/ukrjnd.3(39).2013.09.
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This is review of aminoglycoside antibiotics pharmacokinetics and pharmacodynamics in patients with normal and impaired renal function. Dosing of different aminoglycosides in patients with different stage of renal function impairment and different modalities of renal replacement therapy are highlighted.
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Thacharodi, Aswin, i Iain L. Lamont. "Aminoglycoside-Modifying Enzymes Are Sufficient to Make Pseudomonas aeruginosa Clinically Resistant to Key Antibiotics". Antibiotics 11, nr 7 (1.07.2022): 884. http://dx.doi.org/10.3390/antibiotics11070884.
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Aminoglycosides are widely used to treat infections of Pseudomonas aeruginosa. Genes encoding aminoglycoside-modifying enzymes (AMEs), acquired by horizontal gene transfer, are commonly associated with aminoglycoside resistance, but their effects have not been quantified. The aim of this research was to determine the extent to which AMEs increase the antibiotic tolerance of P. aeruginosa. Bioinformatics analysis identified AME-encoding genes in 48 out of 619 clinical isolates of P. aeruginosa, with ant(2′)-Ia and aac(6′)-Ib3, which are associated with tobramcyin and gentamicin resistance, being the most common. These genes and aph(3′)-VIa (amikacin resistance) were deleted from antibiotic-resistant strains. Antibiotic minimum inhibitory concentrations (MICs) were reduced by up to 64-fold, making the mutated bacteria antibiotic-sensitive in several cases. Introduction of the same genes into four antibiotic-susceptible P. aeruginosa strains increased the MIC by up to 128-fold, making the bacteria antibiotic-resistant in all cases. The cloned genes also increased the MIC in mutants lacking the MexXY-OprM efflux pump, which is an important contributor to aminoglycoside resistance, demonstrating that AMEs and this efflux pump act independently in determining levels of aminoglycoside tolerance. Quantification of the effects of AMEs on antibiotic susceptibility demonstrates the large effect that these enzymes have on antibiotic resistance.
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Sha, Su-Hua, i Jochen Schacht. "Are aminoglycoside antibiotics excitotoxic?" NeuroReport 9, nr 17 (grudzień 1998): 3893–95. http://dx.doi.org/10.1097/00001756-199812010-00023.
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Tulkens, P. M. "Nephrotoxicity of aminoglycoside antibiotics". Toxicology Letters 46, nr 1-3 (marzec 1989): 107–23. http://dx.doi.org/10.1016/0378-4274(89)90121-5.
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Siswanto, Siswanto, i I. Nyoman Sulabda. "The Antibiotics Group Aminoglycosides and Macrolides on Beef in Bali". Journal of Veterinary and Animal Sciences 2, nr 1 (31.01.2019): 39. http://dx.doi.org/10.24843/jvas.2019.v02.i01.p06.
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Animal products may contain certain ingredients that are not good for human health, such as antibiotic residues. The aim of this research is to know the residue of aminoglycoside and macrolide group antibiotics in Bali beef marketed in Bali-Indonesia. The study used 60 samples of meat from merchant in five different markets: Negara, Tabanan, Denpasar, Singaraja, and Klungkung, where each market was taken 12 samples. Screening tests used to determine antibiotic residues in meat. The results showed only 4 positives from 60 samples containing antibiotics, aminoglycoside 2 sempels (3.33%) and marcrolide 1 sempel (1.67%).
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Huth, M. E., A. J. Ricci i A. G. Cheng. "Mechanisms of Aminoglycoside Ototoxicity and Targets of Hair Cell Protection". International Journal of Otolaryngology 2011 (2011): 1–19. http://dx.doi.org/10.1155/2011/937861.
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Aminoglycosides are commonly prescribed antibiotics with deleterious side effects to the inner ear. Due to their popular application as a result of their potent antimicrobial activities, many efforts have been undertaken to prevent aminoglycoside ototoxicity. Over the years, understanding of the antimicrobial as well as ototoxic mechanisms of aminoglycosides has increased. These mechanisms are reviewed in regard to established and potential future targets of hair cell protection.
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Vucovich, Megan M., Robert B. Cotton, Elaine L. Shelton, Jeremy A. Goettel, Noah J. Ehinger, Stanley D. Poole, Naoko Brown i in. "Aminoglycoside-mediated relaxation of the ductus arteriosus in sepsis-associated PDA". American Journal of Physiology-Heart and Circulatory Physiology 307, nr 5 (1.09.2014): H732—H740. http://dx.doi.org/10.1152/ajpheart.00838.2013.
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Sepsis is strongly associated with patency of the ductus arteriosus (PDA) in critically ill newborns. Inflammation and the aminoglycoside antibiotics used to treat neonatal sepsis cause smooth muscle relaxation, but their contribution to PDA is unknown. We examined whether: 1) lipopolysaccharide (LPS) or inflammatory cytokines cause relaxation of the ex vivo mouse DA; 2) the aminoglycosides gentamicin, tobramycin, or amikacin causes DA relaxation; and 3) newborn infants treated with aminoglycosides have an increased risk of symptomatic PDA (sPDA). Changes in fetal mouse DA tone were measured by pressure myography in response to LPS, TNF-α, IFN-γ, macrophage-inflammatory protein 2, IL-15, IL-13, CXC chemokine ligand 12, or three aminoglycosides. A clinical database of inborn patients of all gestations was analyzed for association between sPDA and aminoglycoside treatment. Contrary to expectation, neither LPS nor any of the inflammatory mediators caused DA relaxation. However, each of the aminoglycosides caused concentration-dependent vasodilation in term and preterm mouse DAs. Pretreatment with indomethacin and N-(G)-nitro-L-arginine methyl ester did not prevent gentamicin-induced DA relaxation. Gentamicin-exposed DAs developed less oxygen-induced constriction than unexposed DAs. Among 488,349 infants who met the study criteria, 40,472 (8.3%) had sPDA. Confounder-adjusted odds of sPDA were higher in gentamicin-exposed infants, <25 wk and >32 wk. Together, these findings suggest that factors other than inflammation contribute to PDA. Aminoglycoside-induced vasorelaxation and inhibition of oxygen-induced DA constriction support the paradox that antibiotic treatment of sepsis may contribute to DA relaxation. This association was also found in newborn infants, suggesting that antibiotic selection may be an important consideration in efforts to reduce sepsis-associated PDA.
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Bellucci, Maria Cristina, i Alessandro Volonterio. "Aminoglycosides: From Antibiotics to Building Blocks for the Synthesis and Development of Gene Delivery Vehicles". Antibiotics 9, nr 8 (11.08.2020): 504. http://dx.doi.org/10.3390/antibiotics9080504.
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Aminoglycosides are a class of naturally occurring and semi synthetic antibiotics that have been used for a long time in fighting bacterial infections. Due to acquired antibiotic resistance and inherent toxicity, aminoglycosides have experienced a decrease in interest over time. However, in the last decade, we are seeing a renaissance of aminoglycosides thanks to a better understanding of their chemistry and mode of action, which had led to new trends of application. The purpose of this comprehensive review is to highlight one of these new fields of application: the use of aminoglycosides as building blocks for the development of liposomal and polymeric vectors for gene delivery. The design, synthetic strategies, ability to condensate the genetic material, the efficiency in transfection, and cytotoxicity as well as when available, the antibacterial activity of aminoglycoside-based cationic lipids and polymers are covered and critically analyzed.
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N. Thabet, Asmaa, Ola A. Hamed i Mamdouh M. Esmat. "Aminoglycoside Resistance Pattern among Hospital Acquired and Community Acquired Methicillin-Resistant Staphylococcus aureus". Egyptian Journal of Medical Microbiology 29, nr 3 (1.07.2020): 65–73. http://dx.doi.org/10.51429/ejmm29309.
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Background: MRSA strains are now resistant many antibiotic groups, such as tetracyclines, aminoglycosides, and lincosamides, and become difficult to treat. Aminoglycosides are valuable antibiotics used for treatment of a variety of staphylococcal infections. Objectives: The aim of this study is to detect aminoglycoside resistance in various hospital acquired and community MRSA strain and to identify the genetic basis of this resistance. Methodology: MRSA strains were isolated and identified manually and VITEK 2 system, antibiotic susceptibility of the isolates was tested by VITEK 2 system and the MIC of various aminoglycosides was measured by E test. Conventional PCR was used to detect the genes responsible for aminoglycoside resistance among the isolates. Results: (33.3%) of CA- MRSA isolates were resistant to Amikacin, (20.8%) to Kanamicin and (37.5%) to Gentamicin, while (65.8%) of HAMRSA strains were resistant to Amikacin, (73.7%) to Kanamycin and (71.1%) to Gentamicin. the aac (6’)-Ie/aph (2”) gene was found in 58.3 % of the strains of CAIs and in 68.4% of the strains of HAIs. There is no significant difference between HAIs and CAIs harboring aac (6’)-Ie/aph (2”) gene (p value 0.419). While aph (3)-IIIa gene was found in 45.8% of the strains of CAIs and in 44.7% of the strains of HAIs. Conclusion: There was a non-significant difference between HAIs and CAIs harboring aph (3)-IIIa gene (p value 0.933). It is important to control development of aminoglycosideresistance in MRSA strains and to monitor the potential developing of new aminoglycoside resistant genes.
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Iyengar, Bhashyam S., Virendra Kumar, Timothy P. Wunz i William A. Remers. "Aminoglycoside antibiotics. 6. Chemical reactions of aminoglycosides with disodium carbenicillin". Journal of Medicinal Chemistry 29, nr 5 (maj 1986): 611–14. http://dx.doi.org/10.1021/jm00155a004.
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Theresylle, Eunike Cynthia, Rehmadanta Sitepu i Chresiani Destianita Yoedistira. "Kajian Resistensi Antibiotik Golongan Aminoglikosida dan Golongan Tetrasiklin". Sainsbertek Jurnal Ilmiah Sains & Teknologi 3, nr 1 (30.09.2022): 334–41. http://dx.doi.org/10.33479/sb.v3i1.211.
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Resistance is the ability of bacteria to resist or stop antibiotics. However, according to the Centers for Disease Control and Prevention (CDC), about 23,000 people die per year from resistance. Resistance begins with exposure to antibiotics, initially there are only one or two bacteria that have a chance to live but can grow and spread. The spread through person to person, inappropriate use of antibiotics due to weak infection control.
So the purpose of this study is to find out how the process of resistance by bacteria, as well as genes that play a role in antibiotic resistance of Aminoglycosides and Tetracyclines. Thus we can wisely use antibiotics,for the medical community, the community and help in efforts to reduce the level of resistance and the impact of other resistance. The research method used is the journal review method of 40 articles which is used as material to compare the results of several research articles. The articles used using Scholar and Pubmed searches were selected based on inclusion and exclusion criteria.
From the results of a journal review that Aminoglycoside and Tetracycline antibiotics have a high level of resistance. Aminoglycoside resistance is due to enzymatic inactivation by AAC,APH and ANT. The most common resistance is the Acetyltransferase (AAC) enzyme, namely the AAC(6')-I gene. Tetracycline resistance occurs by efflux pump mechanism, ribosome protection and enzymatic inactivation. The most common gene is tetM gene on ribosome protection mechanism which is expressed to mediate resistance to several antibiotics such as Doxycycline and Minocycline.
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Haws, C. M., B. D. Winegar i J. B. Lansman. "Block of single L-type Ca2+ channels in skeletal muscle fibers by aminoglycoside antibiotics." Journal of General Physiology 107, nr 3 (1.03.1996): 421–32. http://dx.doi.org/10.1085/jgp.107.3.421.
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The activity of single L-type Ca2+ channels was recorded from cell-attached patches on acutely isolated skeletal muscle fibers from the mouse. The experiments were concerned with the mechanism by which aminoglycoside antibiotics inhibit ion flow through the channel. Aminoglycosides produced discrete fluctuations in the single-channel current when added to the external solution. The blocking kinetics could be described as a simple bimolecular reaction between an aminoglycoside molecule and the open channel. The blocking rate was found to be increased when either the membrane potential was made more negative or the concentration of external permeant ion was reduced. Both of these effects are consistent with a blocking site that is located within the channel pore. Other features of block, however, were incompatible with a simple pore blocking mechanism. Hyperpolarization enhanced the rate of unblocking, even though an aminoglycoside molecule must dissociate from its binding site in the channel toward the external solution against the membrane field. Raising the external permeant ion concentration also enhanced the rate of unblocking. This latter finding suggests that aminglycoside affinity is modified by repulsive interactions that arise when the pore is simultaneously occupied by a permeant ion and an aminoglycoside molecule.
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Ji, Xia, Jin Zou, Haibo Peng, Anne-Sophie Stolle, Ruiqiang Xie, Hongjie Zhang, Bo Peng, John J. Mekalanos i Jun Zheng. "Alarmone Ap4A is elevated by aminoglycoside antibiotics and enhances their bactericidal activity". Proceedings of the National Academy of Sciences 116, nr 19 (19.04.2019): 9578–85. http://dx.doi.org/10.1073/pnas.1822026116.
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Second messenger molecules play important roles in the responses to various stimuli that can determine a cell's fate under stress conditions. Here, we report that lethal concentrations of aminoglycoside antibiotics result in the production of a dinucleotide alarmone metabolite–diadenosine tetraphosphate (Ap4A), which promotes bacterial cell killing by this class of antibiotics. We show that the treatment ofEscherichia coliwith lethal concentrations of kanamycin (Kan) dramatically increases the production of Ap4A. This elevation of Ap4A is dependent on the production of a hydroxyl radical and involves the induction of the Ap4A synthetase lysyl-tRNA synthetase (LysU). Ectopic alteration of intracellular Ap4A concentration via the elimination of the Ap4A phosphatase diadenosine tetraphosphatase (ApaH) and the overexpression of LysU causes over a 5,000-fold increase in bacterial killing by aminoglycosides. This increased susceptibility to aminoglycosides correlates with bacterial membrane disruption. Our findings provide a role for the alarmone Ap4A and suggest that blocking Ap4A degradation or increasing its synthesis might constitute an approach to enhance aminoglycoside killing potency by broadening their therapeutic index and thereby allowing lower nontoxic dosages of these antibiotics to be used in the treatment of multidrug-resistant infections.
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Maurer, Florian P., Vera L. Bruderer, Claudia Ritter, Claudio Castelberg, Guido V. Bloemberg i Erik C. Böttger. "Lack of Antimicrobial Bactericidal Activity in Mycobacterium abscessus". Antimicrobial Agents and Chemotherapy 58, nr 7 (21.04.2014): 3828–36. http://dx.doi.org/10.1128/aac.02448-14.
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ABSTRACTAntibiotic therapy of infections caused by the emerging pathogenMycobacterium abscessusis challenging due to the organism's natural resistance toward most clinically available antimicrobials. We investigated the bactericidal activity of antibiotics commonly administered inM. abscessusinfections in order to better understand the poor therapeutic outcome. Time-kill curves were generated for clinicalM. abscessusisolates,Mycobacterium smegmatis, andEscherichia coliby using antibiotics commonly categorized as bactericidal (amikacin and moxifloxacin) or bacteriostatic (tigecycline and linezolid). In addition, the impact of aminoglycoside-modifying enzymes on the mode of action of substrate and nonsubstrate aminoglycosides was studied by usingM. smegmatisas a model organism. While amikacin and moxifloxacin were bactericidal againstE. coli, none of the tested compounds showed bactericidal activity againstM. abscessus. Further mechanistic investigations of the mode of action of aminoglycosides inM. smegmatisrevealed that the bactericidal activity of tobramycin and gentamicin was restored by disruption of the chromosomalaac(2′) gene in the mycobacterial genome. The lack of bactericidal antibiotics in currently recommended treatment regimens provides a reasonable explanation for the poor therapeutic outcome inM. abscessusinfection. Our findings suggest that chromosomally encoded drug-modifying enzymes play an important role in the lack of aminoglycoside bactericidal activity against rapidly growing mycobacteria.
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Parsons, T. D., A. L. Obaid i B. M. Salzberg. "Aminoglycoside antibiotics block voltage-dependent calcium channels in intact vertebrate nerve terminals." Journal of General Physiology 99, nr 4 (1.04.1992): 491–504. http://dx.doi.org/10.1085/jgp.99.4.491.
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Intrinsic and extrinsic optical signals recorded from the intact nerve terminals of vertebrate neurohypophyses were used to investigate the anatomical site and physiological mechanism of the antagonistic effects of aminoglycoside antibiotics on neurotransmission. Aminoglycoside antibiotics blocked the intrinsic light scattering signal closely associated with neurosecretion in the mouse neurohypophysis in a concentration-dependent manner with an IC50 of approximately 60 microM and the block was relieved by increasing [Ca2+]o. The rank order potency of different aminoglycoside antibiotics for blocking neurosecretion in this preparation was determined to be: neomycin greater than gentamicin = kanamycin greater than streptomycin. Optical recordings of rapid changes in membrane potential using voltage-sensitive dyes revealed that aminoglycoside antibiotics decreased the Ca(2+)-dependent after-hyperpolarization of the normal action potential and both the magnitude and after-hyperpolarization of the regenerative Ca2+ spike. The after-hyperpolarization results from a Ca-activated potassium conductance whose block by aminoglycoside antibiotics was also reversed by increased [Ca2+]o. These studies demonstrate that the capacity of aminoglycoside antibiotics to antagonize neurotransmission can be attributed to the block of Ca channels in the nerve terminal.
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Al-Samarraae, Ikram A. A. "Antibiotic Susceptibility and Molecular Detection of Pseudomonas aeruginosa Isolated from Bovine Mastitis". Iraqi Journal of Veterinary Medicine 43, nr 2 (28.12.2019): 77–85. http://dx.doi.org/10.30539/iraqijvm.v43i2.536.
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This study aimed to isolate Pseudomonas aeruginosa from cattle (bovine) milk with mastitis to characterize its antimicrobial susceptibility against some antibiotics, and to identify aminoglycoside acetyltransferase (aac-3-Ib) gene.A total of 100 bovine milk samples were collected randomly from different local cow farms at districts of Wasit governorate, Iraq. Six P. aeruginosa isolates were obtained using bacterial culture method and further identified by Analytical Profile Index (API-20E). The antibiotic sensitivity test was performed by disc diffusion methods. Among the 5 antibiotics used, the highest resistance (100%) was found with Nalidixic acid andtetracycline, follow by gentamicin (50%) and the lowest resistance rate (16.6%, and 33.3%) was to the ciprofloxacin and cephalothin respectively. PCR was performed for all the gentamicin resistant isolates that be among the aminoglycoside family. The where the frequency of aac(3)-Ib gene have product (530bp) was to 3 of P. aeruginosa isolates. From the finding of present study we concluded that P.aeruginosa thatisolated from mastitic bovinehave been developed resistance against aminoglycosides through presence of aac(3)-Ibgene and the ciprofloxacin and cephalothin can be taken as good choice of treatment
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Baharoglu, Zeynep, Anamaria Babosan i Didier Mazel. "Identification of genes involved in low aminoglycoside-induced SOS response in Vibrio cholerae: a role for transcription stalling and Mfd helicase". Nucleic Acids Research 42, nr 4 (5.12.2013): 2366–79. http://dx.doi.org/10.1093/nar/gkt1259.
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Abstract Sub-inhibitory concentrations (sub-MIC) of antibiotics play a very important role in selection and development of resistances. Unlike Escherichia coli, Vibrio cholerae induces its SOS response in presence of sub-MIC aminoglycosides. A role for oxidized guanine residues was observed, but the mechanisms of this induction remained unclear. To select for V. cholerae mutants that do not induce low aminoglycoside-mediated SOS induction, we developed a genetic screen that renders induction of SOS lethal. We identified genes involved in this pathway using two strategies, inactivation by transposition and gene overexpression. Interestingly, we obtained mutants inactivated for the expression of proteins known to destabilize the RNA polymerase complex. Reconstruction of the corresponding mutants confirmed their specific involvement in induction of SOS by low aminoglycoside concentrations. We propose that DNA lesions formed on aminoglycoside treatment are repaired through the formation of single-stranded DNA intermediates, inducing SOS. Inactivation of functions that dislodge RNA polymerase leads to prolonged stalling on these lesions, which hampers SOS induction and repair and reduces viability under antibiotic stress. The importance of these mechanisms is illustrated by a reduction of aminoglycoside sub-MIC. Our results point to a central role for transcription blocking at DNA lesions in SOS induction, so far underestimated.
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Rahman, Hafizur, Chika Fukushima, Hidetaka Kaya, Takashi Yaeno i Kappei Kobayashi. "Knockout of Tobacco Homologs of Arabidopsis Multi-Antibiotic Resistance 1 Gene Confers a Limited Resistance to Aminoglycoside Antibiotics". International Journal of Molecular Sciences 23, nr 4 (11.02.2022): 2006. http://dx.doi.org/10.3390/ijms23042006.
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To explore a possible recessive selective marker for future DNA-free genome editing by direct delivery of a CRISPR/Cas9-single guide RNA (sgRNA) ribonucleoprotein complex, we knocked out homologs of the ArabidopsisMulti-Antibiotic Resistance 1 (MAR1)/RTS3 gene, mutations of which confer aminoglycoside resistance, in tobacco plants by an efficient Agrobacterium-mediated gene transfer. A Cas9 gene was introduced into Nicotiana tabacum and Nicotiana sylvestris together with an sgRNA gene for one of three different target sequences designed to perfectly match sequences in both S- and T-genome copies of N. tabacumMAR1 homologs (NtMAR1hs). All three sgRNAs directed the introduction of InDels into NtMAR1hs, as demonstrated by CAPS and amplicon sequencing analyses, albeit with varying efficiency. Leaves of regenerated transformant shoots were evaluated for aminoglycoside resistance on shoot-induction media containing different aminoglycoside antibiotics. All transformants tested were as sensitive to those antibiotics as non-transformed control plants, regardless of the mutation rates in NtMAR1hs. The NtMAR1hs–knockout seedlings of the T1 generation showed limited aminoglycoside resistance but failed to form shoots when cultured on shoot-induction media containing kanamycin. The results suggest that, like Arabidopsis MAR1, NtMAR1hs have a role in plants’ sensitivity to aminoglycoside antibiotics, and that tobacco has some additional functional homologs.