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Affiliation(s)
- Rustam Aminov
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, United Kingdom
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2
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Majeed Issa O, Abdul-Elah Bakir W, Ayad Abbas M. Laboratory diagnosis of urinary tract infections in patients with resistance genes towards antibiotics. BIONATURA 2022. [DOI: 10.21931/rb/2022.07.02.46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Escherichia coli are gram-negative bacteria that cause urinary tract infections (UTIs). UTIs have affected a significant percentage of humans yearly due to bacterial infection. Our study aims to determine the prevalence of resistance genes in E. coli towards sulfamethoxazole. This study included (490) patients with UTIs, and the urine samples were cultured on media. The patients were admitted to the Medical City in Baghdad to treat UTIs. 116 E.coli isolates were isolated from urine specimens, 35 isolates of them were resistant to trimethoprim/sulfamethoxazole, and 81 isolates were sensitive to trimethoprim/sulfamethoxazole; the E. coli isolates were submitted to multiplex PCR to detection some resistance genes (Sul1, sul2) after detected the isolates by PCR depending on 16S rRNA. Our study showed that identified E. coli was (91-99%) depending on the number of the examined samples by the Vitek 2 system. The molecular study included extraction of chromosomal DNA from (53) E. coli isolates; 35 samples were taken resistant to antibiotics, while from the total of 81 sensitive isolates, only 18 sensitive samples were taken from that are the most sensitive to Timethprime/sulfamethoxazole, then identification by 16S rRNA gene. Detection of Sulfonamides resistance genes included sul1 and sul2. The results showed the 16S rRNA gene identification found in all E. coli isolates and the detection of antibiotic resistance genes. The resistant isolates with the Sul1 gene prevalence were 11(31%), while the sensitive isolates with Sul1gene were 1(6%).
Moreover, the resisted isolates with Sul2 gene prevalence was 8(23%), while the sensitive isolates with the Sul1 gene were 0(0%). The numbers of the resistant isolates were (11) and (8) that carry the Sul1 gene and Sul2 gene, respectively, while the numbers of the sensitive isolates were (1) and (0), respectively. We can conclude that a high percentage of Sul1 gene and Sul2 genes in E. coil isolated from UTIs were high.
Keywords. UTI, Sul1, Sul2, resistant gene, trimethoprim-sulfamethoxazole
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Affiliation(s)
- Oday Majeed Issa
- Department of Microbiology, College of Medicine, Mustansiriyah University, Baghdad IRQA
| | | | - Mohammed Ayad Abbas
- Department of Microbiology, College of Medicine, Mustansiriyah University, Baghdad IRQA
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3
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Reis PA, Castro-Faria-Neto HC. Systemic Response to Infection Induces Long-Term Cognitive Decline: Neuroinflammation and Oxidative Stress as Therapeutical Targets. Front Neurosci 2022; 15:742158. [PMID: 35250433 PMCID: PMC8895724 DOI: 10.3389/fnins.2021.742158] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 12/31/2021] [Indexed: 12/29/2022] Open
Abstract
In response to pathogens or damage signs, the immune system is activated in order to eliminate the noxious stimuli. The inflammatory response to infectious diseases induces systemic events, including cytokine storm phenomenon, vascular dysfunction, and coagulopathy, that can lead to multiple-organ dysfunction. The central nervous system (CNS) is one of the major organs affected, and symptoms such as sickness behavior (depression and fever, among others), or even delirium, can be observed due to activation of endothelial and glial cells, leading to neuroinflammation. Several reports have been shown that, due to CNS alterations caused by neuroinflammation, some sequels can be developed in special cognitive decline. There is still no any treatment to avoid cognitive impairment, especially those developed due to systemic infectious diseases, but preclinical and clinical trials have pointed out controlling neuroinflammatory events to avoid the development of this sequel. In this minireview, we point to the possible mechanisms that triggers long-term cognitive decline, proposing the acute neuroinflammatory events as a potential therapeutical target to treat this sequel that has been associated to several infectious diseases, such as malaria, sepsis, and, more recently, the new SARS-Cov2 infection.
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Affiliation(s)
- Patricia Alves Reis
- Laboratory of Immunopharmacology, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
- Biochemistry Department, Roberto Alcântara Gomes Biology Institute, Rio de Janeiro State University, Rio de Janeiro, Brazil
- *Correspondence: Patricia Alves Reis,
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4
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Clinical Biofilm Ring Test ® Reveals the Potential Role of β-Lactams in the Induction of Biofilm Formation by P. aeruginosa in Cystic Fibrosis Patients. Pathogens 2020; 9:pathogens9121065. [PMID: 33352641 PMCID: PMC7766936 DOI: 10.3390/pathogens9121065] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 12/03/2022] Open
Abstract
Biofilms are characterized by high tolerance to antimicrobials. However, conventional antibiograms are performed on planktonic microorganisms. Through the clinical Biofilm Ring Test® (cBRT), initially aimed to measure the adhesion propensity of bacteria, we discerned a variable distribution of biofilm-producer strains among P. aeruginosa samples isolated from expectorations of cystic fibrosis (CF) patients. Despite a majority of spontaneous adherent isolates, few strains remained planktonic after 5 h of incubation. Their analysis by an adapted protocol of the cBRT revealed an induction of the biofilm early formation by sub-inhibitory doses of β-lactams. Microscopic observations of bacterial cultures stained with Syto 9/Propidium Iodide (PI) confirmed the ability of antimicrobials to increase either the bacterial biomass or the biovolume occupied by induced sessile cells. Finally, the cBRT and its derivatives enabled to highlight in a few hours the potential inducer property of antibiotics on bacterial adhesion. This phenomenon should be considered carefully in the context of CF since patients are constantly under fluctuating antimicrobial treatments. To conclude, assays derived from the Biofilm Ring Test® (BRT) device, not only define efficient doses preventing biofilm formation, but could be useful for the antimicrobial selection in CF, to avoid inducer molecules of the early biofilm initiation.
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5
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Pishchany G, Kolter R. On the possible ecological roles of antimicrobials. Mol Microbiol 2020; 113:580-587. [PMID: 31975454 DOI: 10.1111/mmi.14471] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 01/13/2020] [Accepted: 01/17/2020] [Indexed: 12/29/2022]
Abstract
The Introduction of antibiotics into the clinical use in the middle of the 20th century had a profound impact on modern medicine and human wellbeing. The contribution of these wonder molecules to public health and science is hard to overestimate. Much research has informed our understanding of antibiotic mechanisms of action and resistance at inhibitory concentrations in the lab and in the clinic. Antibiotics, however, are not a human invention as most of them are either natural products produced by soil microorganisms or semisynthetic derivatives of natural products. Because we use antibiotics to inhibit the bacterial growth, it is generally assumed that growth inhibition is also their primary ecological function in the environment. Nevertheless, multiple studies point to diverse nonlethal effects that are exhibited at lower levels of antibiotics. Here we review accumulating evidence of antibiosis and of alternative functions of antibiotics exhibited at subinhibitory concentrations. We also speculate on how these effects might alter phenotypes, fitness, and community composition of microbes in the context of the environment and suggest directions for future research.
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Affiliation(s)
- Gleb Pishchany
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Roberto Kolter
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
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6
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Ejuh G, Fonkem C, Tadjouteu Assatse Y, Yossa Kamsi R, Nya T, Ndukum L, Ndjaka J. Study of the structural, chemical descriptors and optoelectronic properties of the drugs Hydroxychloroquine and Azithromycin. Heliyon 2020; 6:e04647. [PMID: 32802983 PMCID: PMC7417266 DOI: 10.1016/j.heliyon.2020.e04647] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/29/2020] [Accepted: 08/03/2020] [Indexed: 12/23/2022] Open
Abstract
Density functional theory (DFT) was performed in order to predict the structural, chemical descriptors and optoelectronic properties of the drugs Hydroxychloroquine and Azithromycin using the wB97XD, O3LYP and B3LYP functional with 6-31+G(d,p) basis set. It is observed from our studies that most of the descriptors presented show association with some processes, including absorption, blood-brain barrier transport, binding and even toxicity. Hence, the treatment of COVID-19 using Hydroxychloroquine and Azithromycin in some patients as single dose and their combination in patients with Corona virus resistance can be more effective. Our results show that these therapeutic molecules may also have good nonlinear optical applications, may have semiconductor character with wide band gap and can also be promising materials in the production of optoelectronic devices. The density of states and thermodynamic properties were equally determined.
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Affiliation(s)
- G.W. Ejuh
- University of Bamenda, National Higher Polytechnic Institute, Department of Electrical and Electronic Engineering, P. O. Box 39 Bambili, Cameroon
- University of Dschang, IUT-FV Bandjoun, Department of General and Scientific Studies, P.O. Box 134, Bandjoun, Cameroon
| | - C. Fonkem
- University of Yaoundé I, Faculty of Science, Department of Physics, P.O. Box 812 Yaounde, Cameroon
| | - Y. Tadjouteu Assatse
- University of Yaoundé I, Faculty of Science, Department of Physics, P.O. Box 812 Yaounde, Cameroon
| | - R.A. Yossa Kamsi
- University of Yaoundé I, Faculty of Science, Department of Physics, P.O. Box 812 Yaounde, Cameroon
| | - Tchangnwa Nya
- University of Maroua, Faculty of Science, Department of Physics, P.O. Box 814 Maroua, Cameroon
| | - L.P. Ndukum
- University of Bamenda, National Higher Polytechnic Institute, Department of Computer Engineering, P. O. Box 39 Bambili, Cameroon
| | - J.M.B. Ndjaka
- University of Yaoundé I, Faculty of Science, Department of Physics, P.O. Box 812 Yaounde, Cameroon
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Hunt A, Kirsch DR. Decision making in the pharmaceutical industry - A tale of three antibiotics. Int J Pharm 2020; 581:119251. [PMID: 32209367 DOI: 10.1016/j.ijpharm.2020.119251] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/18/2020] [Accepted: 03/20/2020] [Indexed: 11/28/2022]
Abstract
There is a mounting crisis in treatment of bacterial diseases. The appearance of nosocomial infections produced by multi-drug resistant bacteria is rapidly increasing and at the same time the pharmaceutical industry has been abandoning new antibiotic discovery. To help understand why, we investigated the decision-making processes behind three novel antibiotics that were initially discovered in the late 1980's and early 1990's: daptomycin, linezolid, and lysobactin. Each antibiotic was investigated by two highly qualified scientific organizations that came to opposing opinions regarding the clinical utility and commercial potential of the drug. After reviewing the literature and interviewing key scientific staff members working on each of these molecules, we have identified factors needed to generate positive development decisions. Organizational factors included decision timing, therapeutic area focus, organizational support for risk taking and the presence of a project champion. Technical factors included investment in the optimization of dosing for improved drug exposure, toxicological evaluation of the purified eutomer from a diastereomer and the failure to develop an effective research formulation.
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Affiliation(s)
- Avery Hunt
- Biotechnology Department, Harvard Extension School, 51 Brattle Street, Cambridge, MA, 02138, United States
| | - Donald R Kirsch
- Biotechnology Department, Harvard Extension School, 51 Brattle Street, Cambridge, MA, 02138, United States.
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9
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Altube MJ, Martínez MMB, Malheiros B, Maffía PC, Barbosa LRS, Morilla MJ, Romero EL. Fast Biofilm Penetration and Anti-PAO1 Activity of Nebulized Azithromycin in Nanoarchaeosomes. Mol Pharm 2019; 17:70-83. [DOI: 10.1021/acs.molpharmaceut.9b00721] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Maria Julia Altube
- Nanomedicine Research and Development Centre, Science and Technology Department, National University of Quilmes, 1876 Bernal, Buenos Aires, Argentina
| | - Melina M. B. Martínez
- Laboratorio de Microbiología Molecular, Instituto de Microbiología Básica y Aplicada, Universidad Nacional de Quilmes, 1876 Bernal, Buenos Aires, Argentina
| | - Barbara Malheiros
- Institute of Physics, University of São Paulo (USP), 05508-900 São Paulo, Brazil
| | - Paulo C. Maffía
- Laboratorio de Microbiología Molecular, Instituto de Microbiología Básica y Aplicada, Universidad Nacional de Quilmes, 1876 Bernal, Buenos Aires, Argentina
| | | | - Maria Jose Morilla
- Nanomedicine Research and Development Centre, Science and Technology Department, National University of Quilmes, 1876 Bernal, Buenos Aires, Argentina
| | - Eder Lilia Romero
- Nanomedicine Research and Development Centre, Science and Technology Department, National University of Quilmes, 1876 Bernal, Buenos Aires, Argentina
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Martirosyan A, Aminov R, Manukyan G. Environmental Triggers of Autoreactive Responses: Induction of Antiphospholipid Antibody Formation. Front Immunol 2019; 10:1609. [PMID: 31354742 PMCID: PMC6635959 DOI: 10.3389/fimmu.2019.01609] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 06/27/2019] [Indexed: 12/19/2022] Open
Abstract
Antiphospholipid antibodies (aPLs) comprise a diverse family of autoantibodies targeted against proteins with the affinity toward negatively charged phospholipids or protein-phospholipid complexes. Their clinical significance, including prothrombotic potential of anti-cardiolipin antibodies (aCLs), anti-β2-glycoprotein I antibodies (aβ2-GPIs), and lupus anti-coagulant (LA), is well-established. However, the ontogeny of these pathogenic aPLs remains less clear. While transient appearance of aPLs could be induced by various environmental factors, in genetically predisposed individuals these factors may eventually lead to the development of the antiphospholipid syndrome (APS). Since the first description of APS, it has been found that a wide variety of microbial and viral agents influence aPLs production and contribute to clinical manifestations of APS. Many theories attempted to explain the pathogenic potential of different environmental factors as well as a phenomenon termed molecular mimicry between β2-GPI molecule and infection-relevant structures. In this review, we summarize and critically assess the pathogenic and non-pathogenic formation of aPLs and its contribution to the development of APS.
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Affiliation(s)
- Anush Martirosyan
- Laboratory of Molecular and Cellular Immunology, Institute of Molecular Biology, Yerevan, Armenia.,Russian-Armenian (Slavonic) University, Yerevan, Armenia
| | - Rustam Aminov
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, United Kingdom
| | - Gayane Manukyan
- Laboratory of Molecular and Cellular Immunology, Institute of Molecular Biology, Yerevan, Armenia.,Russian-Armenian (Slavonic) University, Yerevan, Armenia
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11
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Enhanced engineered ZnO nanostructures and their antibacterial activity against urinary, gastrointestinal, respiratory and dermal genital infections. APPLIED NANOSCIENCE 2019. [DOI: 10.1007/s13204-019-00996-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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12
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Erythromycin acts through the ghrelin receptor to attenuate inflammatory responses in chondrocytes and maintain joint integrity. Biochem Pharmacol 2019; 165:79-90. [PMID: 30862504 DOI: 10.1016/j.bcp.2019.03.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 03/08/2019] [Indexed: 12/11/2022]
Abstract
Osteoarthritis (OA) is a prevalent disease characterized by chronic joint degeneration and low-grade localized inflammation. There is no available treatment to delay OA progression. We report that in human primary articular chondrocytes, erythromycin, a well-known macrolide antibiotic, had the ability to inhibit pro-inflammatory cytokine Interleukin 1β (IL-1β)-induced catabolic gene expression and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation. Furthermore, erythromycin inhibited monosodium iodoacetate (MIA)-induced joint inflammation and cartilage matrix destruction in mice, an arthritis model that reflects the inflammatory and cartilage matrix loss aspects of OA. EM900, an erythromycin-derivative lacking antibiotic function, had the same activity as erythromycin in vitro and in vivo, indicating distinct anti-inflammatory and antibiotic properties. Using an antibody against erythromycin, we found erythromycin was present on chondrocytes in a dose-dependent manner. The association of erythromycin with chondrocytes was diminished in ghrelin receptor null chondrocytes, and administration of the ghrelin ligand prevented the association of erythromycin with chondrocytes. Importantly, the anti-inflammatory activity of erythromycin was diminished in ghrelin receptor null chondrocytes. Moreover, erythromycin could not exert its chondroprotective effect in ghrelin receptor null mice, and the loss of ghrelin receptor further augmented joint damage upon MIA-injection. Therefore, our study identified a novel pharmacological mechanism for how erythromycin exerts its chondroprotective effect. This mechanism entails ghrelin receptor signaling, which is necessary for alleviating inflammation and joint destruction.
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13
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Ramakrishnan B, Venkateswarlu K, Sethunathan N, Megharaj M. Local applications but global implications: Can pesticides drive microorganisms to develop antimicrobial resistance? THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 654:177-189. [PMID: 30445319 DOI: 10.1016/j.scitotenv.2018.11.041] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 11/02/2018] [Accepted: 11/03/2018] [Indexed: 05/07/2023]
Abstract
Pesticides are an important agricultural input, and the introduction of new active ingredients with increased efficiencies drives their higher production and consumption worldwide. Inappropriate application and storage of these chemicals often contaminate plant tissues, air, water, or soil environments. The presence of pesticides can lead to developing tolerance, resistance or persistence and even the capabilities to degrade them by the microbiomes of theses environments. The pesticide-degrading microorganisms gain and employ several mechanisms for attraction (chemotaxis), membrane transport systems, efflux pumps, enzymes and genetical make-up with plasmid and chromosome encoded catabolic genes for degradation. Even the evolution and the mechanisms of inheritance for pesticide-degradation as a functional trait in several microorganisms are beginning to be understood. Because of the commonalities in the microbial responses of sensing and uptake, and adaptation due to the selection pressures of pesticides and antimicrobial substances including antibiotics, the pesticide-degraders have higher chances of possessing antimicrobial resistance as a surplus functional trait. This review critically examines the probabilities of pesticide contamination of soil and foliage, the knowledge gaps in the regulation and storage of pesticide chemicals, and the human implications of pesticide-degrading microorganisms with antimicrobial resistance in the global strategy of 'One Health'.
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Affiliation(s)
| | - Kadiyala Venkateswarlu
- Formerly Department of Microbiology, Sri Krishnadevaraya University, Anantapur 515055, India
| | - Nambrattil Sethunathan
- Flat No. 103, Ushodaya Apartments, Sri Venkateswara Officers Colony, Ramakrishnapuram, Secunderabad 500056, India
| | - Mallavarapu Megharaj
- Global Centre for Environmental Remediation (GCER) and Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), University of Newcastle, ATC Building, Callaghan, NSW 2308, Australia.
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14
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Barreiro C, Martínez-Castro M. Regulation of the phosphate metabolism in Streptomyces genus: impact on the secondary metabolites. Appl Microbiol Biotechnol 2019; 103:1643-1658. [DOI: 10.1007/s00253-018-09600-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 12/20/2018] [Accepted: 12/21/2018] [Indexed: 12/30/2022]
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15
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Exploration of the Biosynthetic Potential of the Populus Microbiome. mSystems 2018; 3:mSystems00045-18. [PMID: 30320216 PMCID: PMC6172771 DOI: 10.1128/msystems.00045-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 08/17/2018] [Indexed: 01/13/2023] Open
Abstract
The plant root microbiome is one of the most diverse and abundant biological communities known. Plant-associated bacteria can have a profound effect on plant growth and development, and especially on protection from disease and environmental stress. These organisms are also known to be a rich source of antibiotic and antifungal drugs. In order to better understand the ways bacterial communities influence plant health, we evaluated the diversity and uniqueness of the natural product gene clusters in bacteria isolated from poplar trees. The complex molecule clusters are abundant, and the majority are unique, suggesting a great potential to discover new molecules that could not only affect plant health but also could have applications as antibiotic agents. Natural products (NPs) isolated from bacteria have dramatically advanced human society, especially in medicine and agriculture. The rapidity and ease of genome sequencing have enabled bioinformatics-guided NP discovery and characterization. As a result, NP potential and diversity within a complex community, such as the microbiome of a plant, are rapidly expanding areas of scientific exploration. Here, we assess biosynthetic diversity in the Populus microbiome by analyzing both bacterial isolate genomes and metagenome samples. We utilize the fully sequenced genomes of isolates from the Populus root microbiome to characterize a subset of organisms for NP potential. The more than 3,400 individual gene clusters identified in 339 bacterial isolates, including 173 newly sequenced organisms, were diverse across NP types and distinct from known NP clusters. The ribosomally synthesized and posttranslationally modified peptides were both widespread and divergent from previously characterized molecules. Lactones and siderophores were prevalent in the genomes, suggesting a high level of communication and pressure to compete for resources. We then consider the overall bacterial diversity and NP variety of metagenome samples compared to the sequenced isolate collection and other plant microbiomes. The sequenced collection, curated to reflect the phylogenetic diversity of the Populus microbiome, also reflects the overall NP diversity trends seen in the metagenomic samples. In our study, only about 1% of all clusters from sequenced isolates were positively matched to a previously characterized gene cluster, suggesting a great opportunity for the discovery of novel NPs involved in communication and control in the Populus root microbiome. IMPORTANCE The plant root microbiome is one of the most diverse and abundant biological communities known. Plant-associated bacteria can have a profound effect on plant growth and development, and especially on protection from disease and environmental stress. These organisms are also known to be a rich source of antibiotic and antifungal drugs. In order to better understand the ways bacterial communities influence plant health, we evaluated the diversity and uniqueness of the natural product gene clusters in bacteria isolated from poplar trees. The complex molecule clusters are abundant, and the majority are unique, suggesting a great potential to discover new molecules that could not only affect plant health but also could have applications as antibiotic agents.
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Travis A, Chernova O, Chernov V, Aminov R. Antimicrobial drug discovery: lessons of history and future strategies. Expert Opin Drug Discov 2018; 13:983-985. [PMID: 30136874 DOI: 10.1080/17460441.2018.1515910] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Anthony Travis
- a Institute of Biological and Environmental Sciences , Univercity of Aberdeen , Aberdeen , UK
| | - Olga Chernova
- b Kazan Institute of Biochemistry and Biophysics , FRC Kazan Scientific Centre of RAS , Kazan , Russian Federation.,c Kazan (Volga region) Federal University , Kazan , Russian Federation
| | - Vladislav Chernov
- b Kazan Institute of Biochemistry and Biophysics , FRC Kazan Scientific Centre of RAS , Kazan , Russian Federation.,c Kazan (Volga region) Federal University , Kazan , Russian Federation
| | - Rustam Aminov
- d School of Medicine and Dentistry , University of Aberdeen , Aberdeen , UK
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17
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PA5470 Counteracts Antimicrobial Effect of Azithromycin by Releasing Stalled Ribosome in Pseudomonas aeruginosa. Antimicrob Agents Chemother 2018; 62:AAC.01867-17. [PMID: 29203495 DOI: 10.1128/aac.01867-17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 11/23/2017] [Indexed: 12/21/2022] Open
Abstract
Pseudomonas aeruginosa causes various acute and chronic infections in humans. Treatment with azithromycin (AZM) has been shown to benefit patients with chronic P. aeruginosa infections. By binding to the exit tunnel of the 50S ribosome, AZM causes ribosome stalling and depletion of the intracellular tRNA pool. It has been shown that AZM is able to kill stationary-phase P. aeruginosa cells and repress quorum sensing-regulated virulence factors as well as swarming motility. In P. aeruginosa, the PA5470 gene encodes a putative peptide chain release factor whose expression is highly induced by macrolide antibiotics. However, its function remains unknown. Here, we found that overexpression of PA5470 increased bacterial tolerance against AZM and alleviated the repression of swarming motility. Ribosome pulldown assays revealed that PA5470 contributes to the release of ribosome stalled by AZM. We further demonstrate that overexpression of PA5470 counteracts AZM-mediated repression of the translation of the quorum sensing regulator RhlR. Overall, our results revealed a novel role of PA5470 in the bacterial response to AZM.
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Abedon ST, García P, Mullany P, Aminov R. Editorial: Phage Therapy: Past, Present and Future. Front Microbiol 2017. [PMID: 28663740 DOI: 10.3389/fmicb.2017.00981.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Stephen T Abedon
- Department of Microbiology, The Ohio State UniversityMansfield, OH, United States
| | - Pilar García
- Spanish National Research CouncilVillaviciosa, Spain
| | - Peter Mullany
- Department of Microbial Diseases, Eastman Dental Institute, University College LondonLondon, United Kingdom
| | - Rustam Aminov
- School of Medicine and Dentistry, University of AberdeenAberdeen, United Kingdom
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Abedon ST, García P, Mullany P, Aminov R. Editorial: Phage Therapy: Past, Present and Future. Front Microbiol 2017; 8:981. [PMID: 28663740 PMCID: PMC5471325 DOI: 10.3389/fmicb.2017.00981] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 05/16/2017] [Indexed: 12/13/2022] Open
Affiliation(s)
- Stephen T. Abedon
- Department of Microbiology, The Ohio State UniversityMansfield, OH, United States
| | - Pilar García
- Spanish National Research CouncilVillaviciosa, Spain
| | - Peter Mullany
- Department of Microbial Diseases, Eastman Dental Institute, University College LondonLondon, United Kingdom
| | - Rustam Aminov
- School of Medicine and Dentistry, University of AberdeenAberdeen, United Kingdom
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Han D, Walsh MC, Kim KS, Hong SW, Lee J, Yi J, Rivas G, Choi Y, Surh CD. Dendritic cell expression of the signaling molecule TRAF6 is required for immune tolerance in the lung. Int Immunol 2017; 29:71-78. [PMID: 28338920 PMCID: PMC5890897 DOI: 10.1093/intimm/dxx011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 03/10/2017] [Indexed: 12/14/2022] Open
Abstract
Immune tolerance in the lung is important for preventing hypersensitivity, such as allergic asthma. Maintenance of tolerance in the lung is established by coordinated activities of poorly understood cellular and molecular mechanisms, including participation of dendritic cells (DCs). We have previously identified DC expression of the signaling molecule TRAF6 as a non-redundant requirement for the maintenance of immune tolerance in the small intestine of mice. Because mucosal tissues share similarities in how they interact with exogenous antigens, we examined the role of DC-expressed TRAF6 in the lung. As with the intestine, we found that the absence TRAF6 expression by DCs led to spontaneous generation of Th2-associated immune responses and increased susceptibility to model antigen-induced asthma. To examine the role of commensal microbiota, mice deficient in TRAF6 in DCs were treated with broad-spectrum antibiotics and/or re-derived on a germ-free (GF) background. Interestingly, we found that antibiotics-treated specific pathogen-free, but not GF, mice showed restored immune tolerance in the absence of DC-expressed TRAF6. We further found that antibiotics mediate microbiota-independent effects on lung T cells to promote immune tolerance in the lung. This work provides both a novel tool for studying immune tolerance in the lung and an advance in our conceptual understanding of potentially common molecular mechanisms of immune tolerance in both the intestine and the lung.
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Affiliation(s)
- Daehee Han
- Academy of Immunology and Microbiology, Institute for Basic Science, Pohang 37666, Republic of Korea.,Department of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 37666, Republic of Korea
| | - Matthew C Walsh
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Kwang Soon Kim
- Academy of Immunology and Microbiology, Institute for Basic Science, Pohang 37666, Republic of Korea.,Department of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 37666, Republic of Korea
| | - Sung-Wook Hong
- Academy of Immunology and Microbiology, Institute for Basic Science, Pohang 37666, Republic of Korea.,Department of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 37666, Republic of Korea
| | - Junyoung Lee
- Academy of Immunology and Microbiology, Institute for Basic Science, Pohang 37666, Republic of Korea.,Department of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 37666, Republic of Korea
| | - Jaeu Yi
- Academy of Immunology and Microbiology, Institute for Basic Science, Pohang 37666, Republic of Korea.,Department of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 37666, Republic of Korea
| | - Gloriany Rivas
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Yongwon Choi
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Charles D Surh
- Academy of Immunology and Microbiology, Institute for Basic Science, Pohang 37666, Republic of Korea.,Department of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 37666, Republic of Korea.,Division of Developmental Immunology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA
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21
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Aminov R. History of antimicrobial drug discovery: Major classes and health impact. Biochem Pharmacol 2016; 133:4-19. [PMID: 27720719 DOI: 10.1016/j.bcp.2016.10.001] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 10/04/2016] [Indexed: 12/12/2022]
Abstract
The introduction of antibiotics into clinical practice revolutionized the treatment and management of infectious diseases. Before the introduction of antibiotics, these diseases were the leading cause of morbidity and mortality in human populations. This review presents a brief history of discovery of the main antimicrobial classes (arsphenamines, β-lactams, sulphonamides, polypeptides, aminoglycosides, tetracyclines, amphenicols, lipopeptides, macrolides, oxazolidinones, glycopeptides, streptogramins, ansamycins, quinolones, and lincosamides) that have changed the landscape of contemporary medicine. Given within a historical timeline context, the review discusses how the introduction of certain antimicrobial classes affected the morbidity and mortality rates due to bacterial infectious diseases in human populations. Problems of resistance to antibiotics of different classes are also extensively discussed.
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Affiliation(s)
- Rustam Aminov
- School of Medicine and Dentistry, University of Aberdeen, Aberdeen AB25 2ZD, United Kingdom.
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22
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Tan H, Zhang L, Weng Y, Chen R, Zhu F, Jin Y, Cheng Z, Jin S, Wu W. PA3297 Counteracts Antimicrobial Effects of Azithromycin in Pseudomonas aeruginosa. Front Microbiol 2016; 7:317. [PMID: 27014238 PMCID: PMC4792872 DOI: 10.3389/fmicb.2016.00317] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 02/29/2016] [Indexed: 01/08/2023] Open
Abstract
Pseudomonas aeruginosa causes acute and chronic infections in human. Its increasing resistance to antibiotics requires alternative treatments that are more effective than available strategies. Among the alternatives is the unconventional usage of conventional antibiotics, of which the macrolide antibiotic azithromycin (AZM) provides a paradigmatic example. AZM therapy is associated with a small but consistent improvement in respiratory function of cystic fibrosis patients suffering from chronic P. aeruginosa infection. Besides immunomodulating activities, AZM represses bacterial genes involved in virulence, quorum sensing, biofilm formation, and motility, all of which are due to stalling of ribosome and depletion of cellular tRNA pool. However, how P. aeruginosa responds to and counteracts the effects of AZM remain elusive. Here, we found that deficiency of PA3297, a gene encoding a DEAH-box helicase, intensified AZM-mediated bacterial killing, suppression of pyocyanin production and swarming motility, and hypersusceptibility to hydrogen peroxide. We demonstrated that expression of PA3297 is induced by the interaction between AZM and ribosome. Importantly, mutation of PA3297 resulted in elevated levels of unprocessed 23S-5S rRNA in the presence of AZM, which might lead to increased susceptibility to AZM-mediated effects. Our results revealed one of the bacterial responses in counteracting the detrimental effects of AZM.
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Affiliation(s)
- Hao Tan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Lu Zhang
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Yuding Weng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Ronghao Chen
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Feng Zhu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Shouguang Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai UniversityTianjin, China; Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, GainesvilleFL, USA
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
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23
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Gaillard T, Dormoi J, Madamet M, Pradines B. Macrolides and associated antibiotics based on similar mechanism of action like lincosamides in malaria. Malar J 2016; 15:85. [PMID: 26873741 PMCID: PMC4752764 DOI: 10.1186/s12936-016-1114-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 01/20/2016] [Indexed: 01/10/2023] Open
Abstract
Malaria, a parasite vector-borne disease, is one of the biggest health threats in tropical regions, despite the availability of malaria chemoprophylaxis. The emergence and rapid extension of Plasmodium falciparum resistance to various anti-malarial drugs has gradually limited the potential malaria therapeutics available to clinicians. In this context, macrolides and associated antibiotics based on similar mechanism of action like lincosamides constitute an interesting alternative in the treatment of malaria. These molecules, whose action spectrum is similar to that of tetracyclines, are typically administered to children and pregnant women. Recent studies have examined the effects of azithromycin and the lincosamide clindamycin, on isolates from different continents. Azithromycin and clindamycin are effective and well tolerated in the treatment of uncomplicated malaria in combination with quinine. This literature review assesses the roles of macrolides and lincosamides in the prophylaxis and treatment of malaria.
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Affiliation(s)
- Tiphaine Gaillard
- Unité de Parasitologie, Département d'Infectiologie de Terrain, Institut de Recherche Biomédicale des Armées, Marseille, France. .,Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Aix Marseille Université, UM 63, CNRS 7278, IRD 198, Inserm, 1095, Marseille, France. .,Fédération des Laboratoires, Hôpital d'Instruction des Armées Saint Anne, Toulon, France.
| | - Jérôme Dormoi
- Unité de Parasitologie, Département d'Infectiologie de Terrain, Institut de Recherche Biomédicale des Armées, Marseille, France. .,Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Aix Marseille Université, UM 63, CNRS 7278, IRD 198, Inserm, 1095, Marseille, France. .,Unité de Parasitologie et d'Entomologie, Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France.
| | - Marylin Madamet
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Aix Marseille Université, UM 63, CNRS 7278, IRD 198, Inserm, 1095, Marseille, France. .,Equipe Résidente de Recherche en Infectiologie Tropicale, Institut de Recherche Biomédicale des Armées, Hôpital d'Instruction des Armées, Marseille, France. .,Centre National de Référence du Paludisme, Marseille, France.
| | - Bruno Pradines
- Unité de Parasitologie, Département d'Infectiologie de Terrain, Institut de Recherche Biomédicale des Armées, Marseille, France. .,Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Aix Marseille Université, UM 63, CNRS 7278, IRD 198, Inserm, 1095, Marseille, France. .,Unité de Parasitologie et d'Entomologie, Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France. .,Centre National de Référence du Paludisme, Marseille, France.
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24
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Ecology of Anti-Biofilm Agents I: Antibiotics versus Bacteriophages. Pharmaceuticals (Basel) 2015; 8:525-58. [PMID: 26371010 PMCID: PMC4588182 DOI: 10.3390/ph8030525] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Revised: 08/30/2015] [Accepted: 09/01/2015] [Indexed: 12/11/2022] Open
Abstract
Bacteriophages, the viruses that infect bacteria, have for decades been successfully used to combat antibiotic-resistant, chronic bacterial infections, many of which are likely biofilm associated. Antibiotics as anti-biofilm agents can, by contrast, be inefficacious against even genetically sensitive targets. Such deficiencies in usefulness may result from antibiotics, as naturally occurring compounds, not serving their producers, in nature, as stand-alone disruptors of mature biofilms. Anti-biofilm effectiveness by phages, by contrast, may result from a combination of inherent abilities to concentrate lytic antibacterial activity intracellularly via bacterial infection and extracellularly via localized population growth. Considered here is the anti-biofilm activity of microorganisms, with a case presented for why, ecologically, bacteriophages can be more efficacious than traditional antibiotics as medically or environmentally applied biofilm-disrupting agents. Four criteria, it can be argued, generally must be met, in combination, for microorganisms to eradicate biofilms: (1) Furnishing of sufficiently effective antibacterial factors, (2) intimate interaction with biofilm bacteria over extended periods, (3) associated ability to concentrate antibacterial factors in or around targets, and, ultimately, (4) a means of physically disrupting or displacing target bacteria. In nature, lytic predators of bacteria likely can meet these criteria whereas antibiotic production, in and of itself, largely may not.
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25
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Nosanchuk JD, Lin J, Hunter RP, Aminov RI. Low-dose antibiotics: current status and outlook for the future. Front Microbiol 2014; 5:478. [PMID: 25309518 PMCID: PMC4159977 DOI: 10.3389/fmicb.2014.00478] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 08/25/2014] [Indexed: 01/02/2023] Open
Affiliation(s)
- Joshua D Nosanchuk
- Department of Medicine, Albert Einstein College of Medicine of Yeshiva University Bronx, NY, USA ; Department of Microbiology and Immunology, Albert Einstein College of Medicine of Yeshiva University Bronx, NY, USA
| | - Jun Lin
- Department of Animal Science, The University of Tennessee Knoxville, TN, USA
| | | | - Rustam I Aminov
- Section for Bacteriology, Pathology, and Parasitology, National Veterinary Institute, Technical University of Denmark Frederiksberg, Denmark
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26
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Abstract
The human food chain begins with upwards of 1,000 species of bacteria that inhabit the intestinal tracts of poultry and livestock. These intestinal denizens are responsible for the health and safety of a major protein source for humans. The use of antibiotics to treat animal diseases was followed by the surprising discovery that antibiotics enhanced food animal growth, and both led to six decades of antibiotic use that has shaped food animal management practices. Perhaps the greatest impact of antibiotic feeding in food animals has been as a selective force in the evolution of their intestinal bacteria, particularly by increasing the prevalence and diversity of antibiotic resistance genes. Future antibiotic use will likely be limited to prudent applications in both human and veterinary medicine. Improved knowledge of antibiotic effects, particularly of growth-promoting antibiotics, will help overcome the challenges of managing animal health and food safety.
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Affiliation(s)
- Heather K Allen
- Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, Iowa 50010; ,
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27
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Imperi F, Leoni L, Visca P. Antivirulence activity of azithromycin in Pseudomonas aeruginosa. Front Microbiol 2014; 5:178. [PMID: 24795709 PMCID: PMC4001013 DOI: 10.3389/fmicb.2014.00178] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 03/31/2014] [Indexed: 11/13/2022] Open
Abstract
Antibiotics represent our bulwark to combat bacterial infections, but the spread of antibiotic resistance compromises their clinical efficacy. Alternatives to conventional antibiotics are urgently needed in order to complement the existing antibacterial arsenal. The macrolide antibiotic azithromycin (AZM) provides a paradigmatic example of an "unconventional" antibacterial drug. Besides its growth-inhibiting activity, AZM displays potent anti-inflammatory properties, as well as antivirulence activity on some intrinsically resistant bacteria, such as Pseudomonas aeruginosa. In this bacterium, the antivirulence activity of AZM mainly relies on its ability to interact with the ribosome, resulting in direct and/or indirect repression of specific subsets of genes involved in virulence, quorum sensing, biofilm formation, and intrinsic antibiotic resistance. Both clinical experience and clinical trials have shown the efficacy of AZM in the treatment of chronic pulmonary infections caused by P. aeruginosa. The aim of this review is to combine results from laboratory studies with evidence from clinical trials in order to unify the information on the in vivo mode of action of AZM in P. aeruginosa infection.
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Affiliation(s)
- Francesco Imperi
- Pasteur Institute-Cenci Bolognetti Foundation and Department of Biology and Biotechnology “C. Darwin”, “Sapienza” University of RomeRome, Italy
| | - Livia Leoni
- Department of Sciences, “Roma Tre” UniversityRome, Italy
| | - Paolo Visca
- Department of Sciences, “Roma Tre” UniversityRome, Italy
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28
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Morita Y, Tomida J, Kawamura Y. Responses of Pseudomonas aeruginosa to antimicrobials. Front Microbiol 2014; 4:422. [PMID: 24409175 PMCID: PMC3884212 DOI: 10.3389/fmicb.2013.00422] [Citation(s) in RCA: 200] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 12/24/2013] [Indexed: 11/29/2022] Open
Abstract
Infections caused by Pseudomonas aeruginosa often are hard to treat; inappropriate chemotherapy readily selects multidrug-resistant P. aeruginosa. This organism can be exposed to a wide range of concentrations of antimicrobials during treatment; learning more about the responses of P. aeruginosa to antimicrobials is therefore important. We review here responses of the bacterium P. aeruginosa upon exposure to antimicrobials at levels below the inhibitory concentration. Carbapenems (e.g., imipenem) have been shown to induce the formation of thicker and more robust biofilms, while fluoroquinolones (e.g., ciprofloxacin) and aminoglycosides (e.g., tobramycin) have been shown to induce biofilm formation. Ciprofloxacin also has been demonstrated to enhance the frequency of mutation to carbapenem resistance. Conversely, although macrolides (e.g., azithromycin) typically are not effective against P. aeruginosa because of the pseudomonal outer-membrane impermeability and efflux, macrolides do lead to a reduction in virulence factor production. Similarly, tetracycline is not very effective against this organism, but is known to induce the type-III secretion system and consequently enhance cytotoxicity of P. aeruginosain vivo. Of special note are the effects of antibacterials and disinfectants on pseudomonal efflux systems. Sub-inhibitory concentrations of protein synthesis inhibitors (aminoglycosides, tetracycline, chloramphenicol, etc.) induce the MexXY multidrug efflux system. This response is known to be mediated by interference with the translation of the leader peptide PA5471.1, with consequent effects on expression of the PA5471 gene product. Additionally, induction of the MexCD-OprJ multidrug efflux system is observed upon exposure to sub-inhibitory concentrations of disinfectants such as chlorhexidine and benzalkonium. This response is known to be dependent upon the AlgU stress response factor. Altogether, these biological responses of P. aeruginosa provide useful clues for the improvement and optimization of chemotherapy in order to appropriately treat pseudomonal infections while minimizing the emergence of resistance.
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Affiliation(s)
- Yuji Morita
- Department of Microbiology, School of Pharmacy, Aichi Gakuin University, Nagoya Japan
| | - Junko Tomida
- Department of Microbiology, School of Pharmacy, Aichi Gakuin University, Nagoya Japan
| | - Yoshiaki Kawamura
- Department of Microbiology, School of Pharmacy, Aichi Gakuin University, Nagoya Japan
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