151
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Bernal P, Molina-Santiago C, Daddaoua A, Llamas MA. Antibiotic adjuvants: identification and clinical use. Microb Biotechnol 2013; 6:445-9. [PMID: 23445397 PMCID: PMC3918149 DOI: 10.1111/1751-7915.12044] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Affiliation(s)
- Patricia Bernal
- Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas-CSIC, 18008 Granada, Spain
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152
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Dastidar SG, Kristiansen JE, Molnar J, Amaral L. Role of Phenothiazines and Structurally Similar Compounds of Plant Origin in the Fight against Infections by Drug Resistant Bacteria. Antibiotics (Basel) 2013; 2:58-72. [PMID: 27029292 PMCID: PMC4790298 DOI: 10.3390/antibiotics2010058] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Revised: 01/28/2013] [Accepted: 01/31/2013] [Indexed: 11/16/2022] Open
Abstract
Phenothiazines have their primary effects on the plasma membranes of prokaryotes and eukaryotes. Among the components of the prokaryotic plasma membrane affected are efflux pumps, their energy sources and energy providing enzymes, such as ATPase, and genes that regulate and code for the permeability aspect of a bacterium. The response of multidrug and extensively drug resistant tuberculosis to phenothiazines shows an alternative therapy for the treatment of these dreaded diseases, which are claiming more and more lives every year throughout the world. Many phenothiazines have shown synergistic activity with several antibiotics thereby lowering the doses of antibiotics administered to patients suffering from specific bacterial infections. Trimeprazine is synergistic with trimethoprim. Flupenthixol (Fp) has been found to be synergistic with penicillin and chlorpromazine (CPZ); in addition, some antibiotics are also synergistic. Along with the antibacterial action described in this review, many phenothiazines possess plasmid curing activities, which render the bacterial carrier of the plasmid sensitive to antibiotics. Thus, simultaneous applications of a phenothiazine like TZ would not only act as an additional antibacterial agent but also would help to eliminate drug resistant plasmid from the infectious bacterial cells.
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Affiliation(s)
- Sujata G Dastidar
- Department of Microbiology, Herbicure Healthcare Bio-Herbal Foundation, 7&8 Metro Garden City, D. H. Road, Pailan Kolkata 700104, India
| | - Jette E Kristiansen
- Institute of Physics and Chemistry, University of Southern Denmark, Memphys, DK 5230, Odense, Denmark
| | - Joseph Molnar
- Department of Medical Microbiology and Immunology, University of Szeged, Dom ter 10, H-6720, Szeged, Hungary
| | - Leonard Amaral
- Department of Medical Microbiology and Immunology, University of Szeged, Dom ter 10, H-6720, Szeged, Hungary.
- Travel Medicine of the CMDT, Institute of Hygiene & Tropical Medicine, Universidade Nova de Lisboa, 100 Rua Junqueira, 1349-008 Lisbon, Portugal.
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153
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Amaral L, Molnar J. Why and how thioridazine in combination with antibiotics to which the infective strain is resistant will cure totally drug-resistant tuberculosis. Expert Rev Anti Infect Ther 2013; 10:869-73. [PMID: 23030326 DOI: 10.1586/eri.12.73] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Over a period of 14 years, the authors have studied thioridazine, an old neuroleptic, that has been shown to have in vitro activity against intracellular Mycobacterium tuberculosis, regardless of its antibiotic resistance status, thioridazine cures infected mice of antibiotic-susceptible and multidrug-resistant tuberculosis (TB) infections and, when used in combination with antibiotics used for therapy of TB, renders the organism significantly more susceptible. This article will describe the authors' further work and the mechanisms by which thioridazine alone and in combination with antibiotics cures an extensively drug-resistant infection and why it is expected to cure totally drug-resistant TB infections as well. The concepts presented are entirely new and because they focus on the activation of killing by nonkilling macrophages where M. tuberculosis normally resides during infection, and coupled to the inhibition of efflux pumps which contribute to the antibiotic-resistant status, effective therapy of any antibiotic-resistant TB infection is possible.
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Affiliation(s)
- Leonard Amaral
- Institute of Hygiene and Tropical Medicine, Universidade Nova de Lisboa, Rua Junqueira 100, 1349-008 Lisbon, Portugal.
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154
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Recent Advances in Multi-Drug Resistance (MDR) Efflux Pump Inhibitors of Gram-Positive Bacteria S. aureus. Antibiotics (Basel) 2013; 2:28-45. [PMID: 27029290 PMCID: PMC4790296 DOI: 10.3390/antibiotics2010028] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 01/29/2013] [Accepted: 01/30/2013] [Indexed: 11/17/2022] Open
Abstract
The paper focuses on recent achievements in the search for new chemical compounds able to inhibit multidrug resistance (MDR) mechanisms in Gram-positive pathogens. An analysis of the results of the search for new efflux pump inhibitors (EPIs) for Gram-positive bacteria, which have been performed over the last decade, indicates that almost all efforts are focused on the NorA (MFS) efflux pump in S. aureus. Considering the chemical structures of the NorA EPIs that have been identified, it can be observed that the most active agents belong to the families of compounds possessing conjugated double bonds, e.g., chalcones, piperine-like compounds, N-cinnamoylphenalkylamides or citral amide derivatives. Indole-, dihydronaphthyl-, 2-chloro-5-bromo-phenyl- or piperidine moieties seem to be profitable for the EPI properties, as well. These results, together with an increasing knowledge about a variety of efflux pumps that are involved in MDR of Gram-positive pathogens underline that further search for new EPIs should pay more attention to develop MDR efflux protein targets, including SMR, MATE, ABC or other members of the MFS family.
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155
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Worthington RJ, Melander C. Combination approaches to combat multidrug-resistant bacteria. Trends Biotechnol 2013; 31:177-84. [PMID: 23333434 DOI: 10.1016/j.tibtech.2012.12.006] [Citation(s) in RCA: 399] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 12/17/2012] [Accepted: 12/19/2012] [Indexed: 12/19/2022]
Abstract
The increasing prevalence of infections caused by multidrug-resistant bacteria is a global health problem that has been exacerbated by the dearth of novel classes of antibiotics entering the clinic over the past 40 years. Herein, we describe recent developments toward combination therapies for the treatment of multidrug-resistant bacterial infections. These efforts include antibiotic-antibiotic combinations, and the development of adjuvants that either directly target resistance mechanisms such as the inhibition of β-lactamase enzymes, or indirectly target resistance by interfering with bacterial signaling pathways such as two-component systems (TCSs). We also discuss screening of libraries of previously approved drugs to identify nonobvious antimicrobial adjuvants.
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156
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Antibiotics for Emerging Pathogens. Infect Dis (Lond) 2013. [DOI: 10.1007/978-1-4614-5719-0_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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157
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Search for new tools to combat Gram-negative resistant bacteria among amine derivatives of 5-arylidenehydantoin. Bioorg Med Chem 2013; 21:135-45. [DOI: 10.1016/j.bmc.2012.10.053] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 10/30/2012] [Accepted: 10/31/2012] [Indexed: 11/23/2022]
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158
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Szumowski JD, Adams KN, Edelstein PH, Ramakrishnan L. Antimicrobial efflux pumps and Mycobacterium tuberculosis drug tolerance: evolutionary considerations. Curr Top Microbiol Immunol 2013; 374:81-108. [PMID: 23242857 PMCID: PMC3859842 DOI: 10.1007/82_2012_300] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The need for lengthy treatment to cure tuberculosis stems from phenotypic drug resistance, also known as drug tolerance, which has been previously attributed to slowed bacterial growth in vivo. We discuss recent findings that challenge this model and instead implicate macrophage-induced mycobacterial efflux pumps in antimicrobial tolerance. Although mycobacterial efflux pumps may have originally served to protect against environmental toxins, in the pathogenic mycobacteria, they appear to have been repurposed for intracellular growth. In this light, we discuss the potential of efflux pump inhibitors such as verapamil to shorten tuberculosis treatment by their dual inhibition of tolerance and growth.
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Affiliation(s)
- John D Szumowski
- Department of Medicine (Division of Infectious Diseases), University of Washington, Seattle, WA, USA,
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159
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Collu F, Vargiu AV, Dreier J, Cascella M, Ruggerone P. Recognition of imipenem and meropenem by the RND-transporter MexB studied by computer simulations. J Am Chem Soc 2012; 134:19146-58. [PMID: 23146101 DOI: 10.1021/ja307803m] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Basic understanding of the means by which multidrug efflux systems can efficiently recognize and transport drugs constitutes a fundamental step toward development of compounds able to tackle the continuous outbreak of new bacterial strains resistant to traditional antibiotics. We applied a series of computational techniques, from molecular docking to molecular dynamics simulations and free energy estimate methods, to determine the differences in the binding properties of imipenem and meropenem, two potent antibiotics of the carbapenem family, to MexB, the RND transporter of the major efflux system of Pseudomonas aeruginosa. We identified and characterized two affinity sites in the periplasmic domain of the transporter, sharing strong similarities with the distal and proximal binding pockets identified in AcrB, the homologue of MexB in Escherichia coli. According to our results, meropenem has a higher affinity to the distal binding pocket than imipenem while both compounds are weakly bound to the proximal pocket. This different behavior is mainly due to the hydration properties of the nonpharmacophore part of the two compounds, being that of imipenem less bulky and hydrophobic. Our data provide for the first time a rationale at molecular level for the experimental evidence indicating meropenem as a compound strongly affected by MexB contrary to imipenem, which is apparently poorly transported by the same pump.
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Affiliation(s)
- Francesca Collu
- Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
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160
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Barnes CA, Rasmussen SL, Petrich JW, Rasmussen MA. Determination of the concentration of potential efflux pump inhibitors, pheophorbide a and pyropheophorbide a, in the feces of animals by fluorescence spectroscopy. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:10456-10460. [PMID: 23002917 DOI: 10.1021/jf3023063] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Efflux pumps are vital bacterial components, and research has demonstrated that some plant compounds such as pheophorbide a (php) possess efflux pump inhibitor (EPI) activity. This study determined the quantity of php present in feces as an indicator of EPI activity. Feces were collected from different species of animals fed a variety of feeds. The chlorophyll metabolites php and pyropheophorbide a (pyp) were determined using fluorescense spectroscopy. The average concentrations [μg/g dry matter (DM) feces] of pyp/php in feces were as follows: guinea pig, 180; goat, 150; rabbit, 150; dairy cow, 120; feedlot cattle, 60; rat, <1; pig, <1; chicken, <1. These data indicate that animals consuming "green" diets will excrete feces with concentrations of php/pyp that exceed levels demonstrated to be inhibitory to bacterial efflux pumps (0.5 μg/mL). The natural presence EPIs in the gastrointestinal tract may modulate the activity of microbial efflux pumps and exert selection pressure upon resident microbial populations.
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161
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Taylor PL, Rossi L, De Pascale G, Wright GD. A forward chemical screen identifies antibiotic adjuvants in Escherichia coli. ACS Chem Biol 2012; 7:1547-55. [PMID: 22698393 DOI: 10.1021/cb300269g] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Multi-drug-resistant infections caused by Gram-negative pathogens are rapidly increasing, highlighting the need for new chemotherapies. Unlike Gram-positive bacteria, where many different chemical classes of antibiotics show efficacy, Gram-negatives are intrinsically insensitive to many antimicrobials including the macrolides, rifamycins, and aminocoumarins, despite intracellular targets that are susceptible to these drugs. The basis for this insensitivity is the presence of the impermeant outer membrane of Gram-negative bacteria in addition to the expression of pumps and porins that reduce intracellular concentrations of many molecules. Compounds that sensitize Gram-negative cells to "Gram-positive antibiotics", antibiotic adjuvants, offer an orthogonal approach to addressing the crisis of multi-drug-resistant Gram-negative pathogens. We performed a forward chemical genetic screen of 30,000 small molecules designed to identify such antibiotic adjuvants of the aminocoumarin antibiotic novobiocin in Escherichia coli. Four compounds from this screen were shown to be synergistic with novobiocin including inhibitors of the bacterial cytoskeleton protein MreB, cell wall biosynthesis enzymes, and DNA synthesis. All of these molecules were associated with altered cell shape and small molecule permeability, suggesting a unifying mechanism for these antibiotic adjuvants. The potential exists to expand this approach as a means to develop novel combination therapies for the treatment of infections caused by Gram-negative pathogens.
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Affiliation(s)
- Patricia L. Taylor
- M.G. DeGroote
Institute for Infectious Disease Research, Department of Biochemistry
and Biomedical Sciences, McMaster University, Hamilton, ON L8S 3Z5, Canada
| | - Laura Rossi
- M.G. DeGroote
Institute for Infectious Disease Research, Department of Biochemistry
and Biomedical Sciences, McMaster University, Hamilton, ON L8S 3Z5, Canada
| | - Gianfranco De Pascale
- M.G. DeGroote
Institute for Infectious Disease Research, Department of Biochemistry
and Biomedical Sciences, McMaster University, Hamilton, ON L8S 3Z5, Canada
| | - Gerard D. Wright
- M.G. DeGroote
Institute for Infectious Disease Research, Department of Biochemistry
and Biomedical Sciences, McMaster University, Hamilton, ON L8S 3Z5, Canada
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162
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Pieren M, Tigges M. Adjuvant strategies for potentiation of antibiotics to overcome antimicrobial resistance. Curr Opin Pharmacol 2012; 12:551-5. [PMID: 22835931 DOI: 10.1016/j.coph.2012.07.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 07/05/2012] [Accepted: 07/06/2012] [Indexed: 12/17/2022]
Abstract
Alarming facts about the occurrence and spreading of multiple antibiotic resistant bacteria have caught the attention of global surveillance authorities and public media. The demand for novel effective antimicrobial drugs is high and on the rise while, at the same time, the supply of fresh 'magic bullets' is drying up. This review summarizes examples of recent strategies for development of adjunctive antibiotic therapies that overcome microbial resistance and thus rejuvenate the existing arsenal of drugs. Recent studies have demonstrated the potential of compounds that inhibit the action of the repressor protein implicated in ethionamide resistance, thus stimulating activation of the drug and thereby restoring the activity of the antibiotic for treatment of Mycobacterium tuberculosis. Such specific interference with regulators or signal transduction mechanisms involved in antibiotic resistance or virulence provides a new toolbox for novel combinations of antimicrobial drugs with adjuvant molecules lacking intrinsic antibiotic activity. In addition to the development of new antibiotics and vaccination initiatives this strategy of restoring or potentiating the activity of existing antibiotics may help to postpone the day when antibiotics are no longer generally efficacious.
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Affiliation(s)
- Michel Pieren
- BioVersys AG, Hochbergerstrasse 60c, c/o Technologycenter, CH-4057 Basel, Switzerland
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163
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Livermore DM. Current epidemiology and growing resistance of gram-negative pathogens. Korean J Intern Med 2012; 27:128-42. [PMID: 22707882 PMCID: PMC3372794 DOI: 10.3904/kjim.2012.27.2.128] [Citation(s) in RCA: 233] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 04/09/2012] [Indexed: 12/24/2022] Open
Abstract
In the 1980s, gram-negative pathogens appeared to have been beaten by oxyimino-cephalosporins, carbapenems, and fluoroquinolones. Yet these pathogens have fought back, aided by their membrane organization, which promotes the exclusion and efflux of antibiotics, and by a remarkable propensity to recruit, transfer, and modify the expression of resistance genes, including those for extended-spectrum β-lactamases (ESBLs), carbapenemases, aminoglycoside-blocking 16S rRNA methylases, and even a quinolone-modifying variant of an aminoglycoside-modifying enzyme. Gram-negative isolates--both fermenters and non-fermenters--susceptible only to colistin and, more variably, fosfomycin and tigecycline, are encountered with increasing frequency, including in Korea. Some ESBLs and carbapenemases have become associated with strains that have great epidemic potential, spreading across countries and continents; examples include Escherichia coli sequence type (ST)131 with CTX-M-15 ESBL and Klebsiella pneumoniae ST258 with KPC carbapenemases. Both of these high-risk lineages have reached Korea. In other cases, notably New Delhi Metallo carbapenemase, the relevant gene is carried by promiscuous plasmids that readily transfer among strains and species. Unless antibiotic stewardship is reinforced, microbiological diagnosis accelerated, and antibiotic development reinvigorated, there is a real prospect that the antibiotic revolution of the 20th century will crumble.
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164
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Why thioridazine in combination with antibiotics cures extensively drug-resistant Mycobacterium tuberculosis infections. Int J Antimicrob Agents 2012; 39:376-80. [PMID: 22445204 DOI: 10.1016/j.ijantimicag.2012.01.012] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 01/18/2012] [Indexed: 11/22/2022]
Abstract
Thioridazine (TDZ) in combination with antibiotics to which extensively drug-resistant Mycobacterium tuberculosis (XDR-TB) is initially resistant yields a cure. This is due to the fact that TDZ enhances the killing of intracellular M. tuberculosis by non-killing macrophages, inhibits the genetic expression of efflux pumps of M. tuberculosis that extrude antibiotics prior to reaching their intended targets, and inhibits the activity of existing efflux pumps that contribute to the multidrug-resistant phenotype of M. tuberculosis. The combination of these effects of TDZ probably contributes to the successful recent cures of XDR-TB cases when the phenothiazine TDZ is used in combination with antibiotics to which the patient with XDR-TB was initially unresponsive.
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165
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Fadli M, Saad A, Sayadi S, Chevalier J, Mezrioui NE, Pagès JM, Hassani L. Antibacterial activity of Thymus maroccanus and Thymus broussonetii essential oils against nosocomial infection - bacteria and their synergistic potential with antibiotics. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2012; 19:464-471. [PMID: 22257599 DOI: 10.1016/j.phymed.2011.12.003] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Revised: 11/14/2011] [Accepted: 12/13/2011] [Indexed: 05/28/2023]
Abstract
The aim of this study was to evaluate the antibacterial effect of the association between conventional antibiotics and essential oils (EOs) of endemic Moroccan thyme species, Thymus maroccanus and T. broussonetii, on antibiotic-resistant bacteria involved in nosocomial infections. Synergistic interactions between antibiotics (ciprofloxacin, gentamicin, pristinamycin, and cefixime) and EOs, and between T. maroccanus and T. Broussonetii EOs were determined by the checkerboard test. Serial dilutions of two antimicrobial agents were mixed together so that each row (and column) contained a fixed amount of the first agent and increasing amounts of the second one. The results indicate that the oils had a high inhibitory activity against tested bacteria, except for Pseudomonas aeruginosa. In parallel with the increase of cellular killing, the release of 260nm-absorbing materials from bacterial cells, treated with EOs, increased in response to oil concentration. Out of 80 combinations tested between EOs and antibiotics, 71% showed total synergism, 20% had partial synergistic interaction and 9% showed no effect. Combination with carvacrol, the major constituent of T. maroccanus and T. broussonetii, showed also an interesting synergistic effect in combination with ciprofloxacin. The effect on Gram-positive bacteria was more important than on Gram-negative bacteria. These findings are very promising since the use of these combinations for nosocomial infections treatment is likely to reduce the minimum effective dose of the antibiotics, thus minimizing their possible toxic side effects and treatment cost. However, further investigations are needed to assess the potential for therapeutic application.
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Affiliation(s)
- Mariam Fadli
- Laboratoire de Biologie et Biotechnologie des Microorganismes, Pôle d'Excellence Régionale AUF, Faculté des Sciences Semlalia, Université Cadi Ayyad, B.P. 2390, 40000 Marrakech, Morocco
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166
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Compounds of Alpinia katsumadai as potential efflux inhibitors in Mycobacterium smegmatis. Bioorg Med Chem 2012; 20:2701-6. [PMID: 22459211 DOI: 10.1016/j.bmc.2012.02.039] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 02/07/2012] [Accepted: 02/08/2012] [Indexed: 11/22/2022]
Abstract
Efflux pumps are one of the well established mechanisms that contribute to antibiotic resistance in bacteria, such as mycobacteria. As a result, the identification of efflux pump inhibitors is an attractive target in antimicrobial therapy. The isolated compounds, three diarylheptanoids, trans,trans-1,7-diphenylhepta-4,6-dien-3-one (1), (5R)-trans-1,7-diphenyl-5-hydroxyhept-6-en-3-one (2), (3S,5S)-trans-1,7-diphenylhept-1-ene-3,5-diol (3) and the flavonoid pinocembrin (4), from Alpinia katsumadai, Zingiberaceae, were examined for their antimycobacterial activity and their synergistic effects with different antibiotics against M. smegmatis mc(2) 155. Furthermore, these compounds were evaluated as potential EtBr efflux inhibitors. Although they showed weak antimycobacterial activities (MIC ≥ 64 mg/L), especially compound 1 revealed a significant activity on the EtBr accumulation and efflux as well as a synergistic effect in combination with rifampicin.
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167
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Smati M, Emond JP, Arlet G, Tankovic J. In Vivo Sequential Selection of Escherichia coli with Topoisomerase- and Efflux-Mediated Misleading Quinolone Resistance Phenotypes. Microb Drug Resist 2012; 18:19-22. [DOI: 10.1089/mdr.2011.0042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Mounira Smati
- Service de Bactériologie, Hôpital Avicenne, APHP, Bobigny and Université Paris, Bobigny, France
| | | | - Guillaume Arlet
- Service de Bactériologie, Hôpital Tenon, APHP, Paris and Université Paris, Paris, France
| | - Jacques Tankovic
- Service de Bactériologie-Virologie, Hôpital Saint-Antoine, APHP, Paris and Université Paris, Paris, France
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168
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Antibiotics for Emerging Pathogens. Infect Dis (Lond) 2012. [DOI: 10.1007/978-1-0716-2463-0_523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
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169
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Genetic response of Salmonella enterica serotype Enteritidis to thioridazine rendering the organism resistant to the agent. Int J Antimicrob Agents 2012; 39:16-21. [DOI: 10.1016/j.ijantimicag.2011.08.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 08/19/2011] [Accepted: 08/24/2011] [Indexed: 01/29/2023]
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170
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Wright G. Antibiotics: A New Hope. ACTA ACUST UNITED AC 2012; 19:3-10. [DOI: 10.1016/j.chembiol.2011.10.019] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 10/12/2011] [Accepted: 10/14/2011] [Indexed: 12/21/2022]
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171
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Abstract
The highly alkaline compound trisodium phosphate (TSP) is used as an intervention to reduce the load of Campylobacter on poultry meat in U.S. poultry slaughter plants. The aim of the present study was to investigate the cellular responses of Campylobacter jejuni NCTC11168 when exposed to sublethal concentrations of TSP. Preexposure of C. jejuni to TSP resulted in a significant increase in heat sensitivity, suggesting that a combined heat and TSP treatment may increase reduction of C. jejuni. A microarray analysis identified a limited number of genes that were differently expressed after sublethal TSP exposure; however, the response was mainly associated with ion transport processes. C. jejuni NCTC11168 nhaA1 (Cj1655c) and nhaA2 (Cj1654c), which encode orthologues to the Escherichia coli NhaA cation/proton antiporter, were able to partially restore TSP, alkaline, and sodium resistance phenotypes to an E. coli cation/proton antiporter mutant. In addition, inhibition of resistance-nodulation-cell division (RND) multidrug efflux pumps by the inhibitor PaβN (Phe-Arg β-naphthylamide dihydrochloride) decreased tolerance to sublethal TSP. Therefore, we propose that NhaA1/NhaA2 cation/proton antiporters and RND multidrug efflux pumps function in tolerance to sublethal TSP exposure in C. jejuni.
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172
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He X, Ahn J. Differential gene expression in planktonic and biofilm cells of multiple antibiotic-resistant Salmonella Typhimurium and Staphylococcus aureus. FEMS Microbiol Lett 2011; 325:180-8. [PMID: 22092573 DOI: 10.1111/j.1574-6968.2011.02429.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 09/27/2011] [Accepted: 09/28/2011] [Indexed: 11/29/2022] Open
Abstract
This study was designed to evaluate gene expression patterns of the planktonic and biofilm cells of Staphylococcus aureus and Salmonella Typhimurium in trypticase soy broth adjusted to pH 5.5 and pH 7.3. The planktonic and biofilm cells of multiple antibiotic-resistant S. aureus (S. aureus(R) ) and S. Typhimurium (S. Typhimurium(R) ) were more resistant to β-lactams than those of antibiotic-susceptible S. aureus (S. aureus(S) ) and S. Typhimurium (S. Typhimurium(S) ) at pH 5.5 and pH 7.3. The relative gene expression levels of norB, norC, and mdeA genes were increased by 7.0-, 4.7-, and 4.6-fold, respectively, in the biofilm cells of S. aureus(S) grown at pH 7.3, while norB, norC, mdeA, sec, seg, sei, sel, sem, sen, and seo genes were stable in the biofilm cells of S. aureus(R) . This study provides useful information for understanding gene expression patterns in the planktonic and biofilm cells of antibiotic-resistance pathogens exposed to acidic stress.
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Affiliation(s)
- Xinlong He
- Department of Biomaterials Engineering, Institute of Bioscience & Biotechnology, Kangwon National University, Chuncheon, South Korea
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173
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Okandeji BO, Greenwald DM, Wroten J, Sello JK. Synthesis and evaluation of inhibitors of bacterial drug efflux pumps of the major facilitator superfamily. Bioorg Med Chem 2011; 19:7679-89. [PMID: 22055717 DOI: 10.1016/j.bmc.2011.10.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2011] [Revised: 09/26/2011] [Accepted: 10/05/2011] [Indexed: 11/26/2022]
Abstract
Inhibitors of drug efflux pumps have great potential as pharmacological agents that restore the drug susceptibility of multidrug resistant bacterial pathogens. Most attention has been focused on the discovery of small molecules that inhibit the resistance nodulation division (RND) family drug efflux pumps in Gram-negative bacteria. The prototypical inhibitor of RND-family efflux pumps in Gram-negative bacteria is MC-207,110 (Phe-Arg-β-naphthylamide), a C-capped dipeptide. Here, we report that C-capped dipeptides inhibit two chloramphenicol-specific efflux pumps in Streptomyces coelicolor, a Gram-positive bacterium that is a relative of the human pathogen Mycobacterium tuberculosis. Diversity-oriented synthesis of a library of structurally related C-capped dipeptides via an Ugi four component reaction and screening of the resulting compounds resulted in the discovery of a compound that is threefold more potent as a suppressor of chloramphenicol resistance in S. coelicolor than MC-207,110. Since chloramphenicol resistance in S. coelicolor is mediated by major facilitator superfamily drug efflux pumps, our findings provide the first evidence that C-capped dipeptides can inhibit drug efflux pumps outside of the RND superfamily.
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Affiliation(s)
- Babajide O Okandeji
- Department of Chemistry, Brown University, 324 Brook Street, Providence, RI 02912, United States
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174
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Mechanisms of and risk factors for fluoroquinolone resistance in clinical Enterococcus faecalis isolates from patients with urinary tract infections. J Clin Microbiol 2011; 49:3912-6. [PMID: 21918020 DOI: 10.1128/jcm.05549-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
We examined Enterococcus faecalis strains clinically isolated from 100 patients with urinary tract infections (UTIs) for their susceptibility to levofloxacin (LVX) by measuring the MIC and investigated amino acid mutations by direct DNA sequencing, which were then correlated with LVX resistance. Next, we studied risk factors for LVX resistance, such as age, gender, and previous fluoroquinolone use, and investigated the statistical correlation of these risk factors with each amino acid mutation and LVX resistance. Of the 100 isolates tested, 14 isolates showed LVX resistance and all of these isolates had amino acid mutations. We demonstrated that 2 out of 4 mutations (Ser83-to-Ile in gyrA and Ser80-to-Ile in parC) had a significant correlation with LVX resistance. There was a significant relationship between isolates with 2 or 3 amino acid mutations and LVX resistance. In addition, we found a significant correlation between the previous use of fluoroquinolones and LVX resistance or the presence of mutations and also demonstrated that previous use of other types of antibiotics was significantly related to the presence of mutations by multivariate analysis. In conclusion, we found significant correlation between amino acid mutations in E. faecalis, LVX resistance, and risk factors such as previous use of fluoroquinolones.
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175
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He X, Ahn J. Survival and virulence properties of multiple antibiotic-resistant Salmonella Typhimurium under simulated gastrointestinal conditions. Int J Food Sci Technol 2011. [DOI: 10.1111/j.1365-2621.2011.02732.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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176
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Nikaido H, Pagès JM. Broad-specificity efflux pumps and their role in multidrug resistance of Gram-negative bacteria. FEMS Microbiol Rev 2011; 36:340-63. [PMID: 21707670 DOI: 10.1111/j.1574-6976.2011.00290.x] [Citation(s) in RCA: 489] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Antibiotic resistance mechanisms reported in Gram-negative bacteria are causing a worldwide health problem. The continuous dissemination of 'multidrug-resistant' (MDR) bacteria drastically reduces the efficacy of our antibiotic 'arsenal' and consequently increases the frequency of therapeutic failure. In MDR bacteria, the overexpression of efflux pumps that expel structurally unrelated drugs contributes to the reduced susceptibility by decreasing the intracellular concentration of antibiotics. During the last decade, several clinical data have indicated an increasing involvement of efflux pumps in the emergence and dissemination of resistant Gram-negative bacteria. It is necessary to clearly define the molecular, functional and genetic bases of the efflux pump in order to understand the translocation of antibiotic molecules through the efflux transporter. The recent investigation on the efflux pump AcrB at its structural and physiological levels, including the identification of drug affinity sites and kinetic parameters for various antibiotics, may pave the way towards the rational development of an improved new generation of antibacterial agents as well as efflux inhibitors in order to efficiently combat efflux-based resistance mechanisms.
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Affiliation(s)
- Hiroshi Nikaido
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
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177
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Fadli M, Chevalier J, Saad A, Mezrioui NE, Hassani L, Pages JM. Essential oils from Moroccan plants as potential chemosensitisers restoring antibiotic activity in resistant Gram-negative bacteria. Int J Antimicrob Agents 2011; 38:325-30. [PMID: 21752605 DOI: 10.1016/j.ijantimicag.2011.05.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 04/29/2011] [Accepted: 05/03/2011] [Indexed: 11/16/2022]
Abstract
Bacterial drug resistance is a worrying public health problem. Antibiotic efflux is a major non-specific resistance mechanism used by bacteria, and efflux pumps are involved in the low-level susceptibility of various important Gram-negative pathogens. Use of molecules that can block bacterial pumps is an attractive strategy, but several studies report only partial efficacy owing to limits of these molecules (stability, selectivity, bioavailability, toxicity, etc.). The objective of this study was to search for natural sources of molecules able to inhibit efflux pump systems of resistant Gram-negative bacteria (Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Salmonella enterica serotype Typhimurium and Pseudomonas aeruginosa). The results indicate that the studied essential oils exhibit interesting activity against the tested bacteria. This activity was significantly enhanced in the presence of an efflux pump inhibitor such as phenylalanine arginyl β-naphthylamide (PAβN). The role of lipopolysaccharide (LPS) structure in the effect of essential oils was also reported in Salmonella LPS deep-rough mutants. In addition, essential oils of Thymus maroccanus and Thymus broussonetii, used at a low concentration (a fraction of the minimum inhibitory concentration), are able to significantly increase chloramphenicol susceptibility of several resistant isolates. These results demonstrate that these essential oils can alter efflux pump activity and may be attractive candidates to develop new drugs for chemosensitising multidrug-resistant strains to clinically used antibiotics.
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Affiliation(s)
- Mariam Fadli
- UMR-MD1, Facultés de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
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178
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Vargiu AV, Collu F, Schulz R, Pos KM, Zacharias M, Kleinekathöfer U, Ruggerone P. Effect of the F610A mutation on substrate extrusion in the AcrB transporter: explanation and rationale by molecular dynamics simulations. J Am Chem Soc 2011; 133:10704-7. [PMID: 21707050 DOI: 10.1021/ja202666x] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The tripartite efflux pump AcrAB-TolC is responsible for the intrinsic and acquired multidrug resistance in Escherichia coli. Its active part, the homotrimeric transporter AcrB, is in charge of the selective binding of substrates and energy transduction. The mutation F610A has been shown to significantly reduce the minimum inhibitory concentration of doxorubicin and many other substrates, although F610 does not appear to interact strongly with them. Biochemical study of transport kinetics in AcrB is not yet possible, except for some β-lactams, and other techniques should supply this important information. Therefore, in this work, we assess the impact of the F610A mutation on the functionality of AcrB by means of computational techniques, using doxorubicin as substrate. We found that the compound slides deeply inside the binding pocket after mutation, increasing the strength of the interaction. During subsequent conformational alterations of the transporter, doxorubicin was either not extruded from the binding site or displaced along a direction other than the one associated with extrusion. Our study indicates how subtle interactions determine the functionality of multidrug transporters, since decreased transport might not be simplistically correlated to decreased substrate binding affinity.
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Affiliation(s)
- Attilio V Vargiu
- CNR-IOM, Unità SLACS, S.P. Monserrato-Sestu Km 0.700, I-09042 Monserrato (CA), Italy.
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179
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Bohnert JA, Szymaniak-Vits M, Schuster S, Kern WV. Efflux inhibition by selective serotonin reuptake inhibitors in Escherichia coli. J Antimicrob Chemother 2011; 66:2057-60. [DOI: 10.1093/jac/dkr258] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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180
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Planson AG, Carbonell P, Grigoras I, Faulon JL. Engineering antibiotic production and overcoming bacterial resistance. Biotechnol J 2011; 6:812-25. [PMID: 21661120 DOI: 10.1002/biot.201100085] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 05/13/2011] [Accepted: 05/16/2011] [Indexed: 01/21/2023]
Abstract
Progress in DNA technology, analytical methods and computational tools is leading to new developments in synthetic biology and metabolic engineering, enabling new ways to produce molecules of industrial and therapeutic interest. Here, we review recent progress in both antibiotic production and strategies to counteract bacterial resistance to antibiotics. Advances in sequencing and cloning are increasingly enabling the characterization of antibiotic biosynthesis pathways, and new systematic methods for de novo biosynthetic pathway prediction are allowing the exploration of the metabolic chemical space beyond metabolic engineering. Moreover, we survey the computer-assisted design of modular assembly lines in polyketide synthases and non-ribosomal peptide synthases for the development of tailor-made antibiotics. Nowadays, production of novel antibiotic can be tranferred into any chosen chassis by optimizing a host factory through specific strain modifications. These advances in metabolic engineering and synthetic biology are leading to novel strategies for engineering antimicrobial agents with desired specificities.
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Affiliation(s)
- Anne-Gaëlle Planson
- Institute of Systems and Synthetic Biology, University of Evry-Val-d'Esonne, 5 rue Henri Desbruères, Evry, France
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181
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Askoura M, Mottawea W, Abujamel T, Taher I. Efflux pump inhibitors (EPIs) as new antimicrobial agents against Pseudomonas aeruginosa. Libyan J Med 2011; 6:LJM-6-5870. [PMID: 21594004 PMCID: PMC3096568 DOI: 10.3402/ljm.v6i0.5870] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 04/20/2011] [Indexed: 11/19/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen and one of the leading causes of nosocomial infections worldwide. The difficulty in treatment of pseudomonas infections arises from being multidrug resistant (MDR) and exhibits resistance to most antimicrobial agents due to the expression of different mechanisms overcoming their effects. Of these resistance mechanisms, the active efflux pumps in Pseudomonas aeruginosa that belong to the resistance nodulation division (RND) plays a very important role in extruding the antibiotics outside the bacterial cells providing a protective means against their antibacterial activity. Beside its role against the antimicrobial agents, these pumps can extrude biocides, detergents, and other metabolic inhibitors. It is clear that efflux pumps can be targets for new antimicrobial agents. Peptidomimetic compounds such as phenylalanine arginyl β-naphthylamide (PAβN) have been introduced as efflux pump inhibitors (EPIs); their mechanism of action is through competitive inhibition with antibiotics on the efflux pump resulting in increased intracellular concentration of antibiotic, hence, restoring its antibacterial activity. The advantage of EPIs is the difficulty to develop bacterial resistance against them, but the disadvantage is their toxic property hindering their clinical application. The structure activity relationship of these compounds showed other derivatives from PAβN that are higher in their activity with higher solubility in biological fluids and decreased toxicity level. This raises further questions on how can we compact Pseudomonas infections. Of particular importance, the recent resurgence in the use of older antibiotics such as polymyxins and probably applying stricter control measures in order to prevent their spread in clinical sittings.
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Affiliation(s)
- Momen Askoura
- Biochemistry, Immunology and Microbiology (BMI) Department, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
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182
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Amaral L, Cerca P, Spengler G, Machado L, Martins A, Couto I, Viveiros M, Fanning S, Pagès JM. Ethidium bromide efflux by Salmonella: modulation by metabolic energy, pH, ions and phenothiazines. Int J Antimicrob Agents 2011; 38:140-5. [PMID: 21565465 DOI: 10.1016/j.ijantimicag.2011.03.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 03/21/2011] [Accepted: 03/22/2011] [Indexed: 11/16/2022]
Abstract
The main efflux pump of Salmonella enterica serotype Enteritidis, which obtains its energy for the extrusion of noxious agents from the proton-motive force, was studied with the aid of an ethidium bromide (EtBr) semi-automated method under conditions that define the role of metabolic energy, ions and pH in the extrusion of the universal substrate EtBr. The results obtained in this study indicate that in minimal medium containing sodium at pH 5 efflux of EtBr is independent of glucose, whereas at pH 8 metabolic energy is an absolute requirement for the maintenance of efflux. In deionised water at pH 5.5, metabolic energy is required for the maintenance of efflux. The inhibitory effect of the ionophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) on efflux is shown to be minimised by low pH, and at high pH by metabolic energy. Similarly, thioridazine, an inhibitor of metabolic enzymes, inhibits efflux of EtBr only at pH 8 and the degree of inhibition is lessened by the presence of metabolic energy.
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Affiliation(s)
- Leonard Amaral
- Grupo de Micobactérias, Unidade de Microbiologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008 Lisboa, Portugal.
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183
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Bolla JM, Alibert-Franco S, Handzlik J, Chevalier J, Mahamoud A, Boyer G, Kieć-Kononowicz K, Pagès JM. Strategies for bypassing the membrane barrier in multidrug resistant Gram-negative bacteria. FEBS Lett 2011; 585:1682-90. [DOI: 10.1016/j.febslet.2011.04.054] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 04/20/2011] [Accepted: 04/21/2011] [Indexed: 10/18/2022]
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184
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Antibacterial properties of compounds isolated from Carpobrotus edulis. Int J Antimicrob Agents 2011; 37:438-44. [DOI: 10.1016/j.ijantimicag.2011.01.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Revised: 01/17/2011] [Accepted: 01/18/2011] [Indexed: 11/17/2022]
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185
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Martins A, Machado L, Costa S, Cerca P, Spengler G, Viveiros M, Amaral L. Role of calcium in the efflux system of Escherichia coli. Int J Antimicrob Agents 2011; 37:410-4. [PMID: 21419607 DOI: 10.1016/j.ijantimicag.2011.01.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 01/11/2011] [Accepted: 01/13/2011] [Indexed: 10/18/2022]
Abstract
Efflux of antibiotics by Escherichia coli AG100 is performed by a variety of efflux pumps, ensuring survival of the bacterium in widely diverse media. At pH 5, efflux is independent of metabolic energy during the period of time the assay is conducted; at pH 8 it is totally dependent upon metabolic energy. Because calcium ions (Ca(2+)) are important for membrane transport channels and the activity of ATPases that provide energy functions, the role of Ca(2+) in the extrusion of an efflux pump substrate under conditions that challenge the bacterium was investigated. Real-time accumulation and efflux of ethidium bromide (EtBr) by E. coli K-12 AG100 strain [argE3 thi-1 rpsL xyl mtl Δ(gal-uvrB) supE44] was determined by a semi-automated fluorometric method in the presence and absence of Ca(2+) and agents that are known to inhibit access of calcium to enzymes that provide energy. Chlorpromazine (CPZ), an inhibitor of calcium binding to proteins (calcium-dependent enzymes), and ethylene diamine tetra-acetic acid (EDTA), a chelator of Ca(2+), increased accumulation and efflux of EtBr at pH 8 but not at pH 5. Ca(2+) reverses these effects when the assay is conducted at pH 8. In conclusion, the activity of the efflux pump system of E. coli is dependent upon metabolic energy at pH 8. Because at pH 8 hydrolysis of ATP is favoured and contributes protons for activation of the AcrAB-TolC efflux pump, CPZ is suspected of having its effects on accumulation/efflux of EtBr by indirectly affecting ATPase activity that is dependent upon Ca(2+).
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Affiliation(s)
- Ana Martins
- Unit of Mycobacteriology, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 96, 1349-008 Lisbon, Portugal
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186
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Abstract
The unremitting emergence of multidrug-resistant bacterial pathogens highlights a matching need for new therapeutic options. For example, new carbapenemases such as KPC (class A Klebsiella pneumoniae) and NDM-1 (New Delhi metallo-β-lactamase 1) are surfacing, resulting in almost total resistance to β-lactam antibiotics. Furthermore, resistance is quickly disseminated, not only in the healthcare sector, but also within the community at large, because many resistance determinants are carried on mobile genetic elements readily shared among pathogens. The absence of new antibiotics has led to a growing reliance on older, more toxic drugs such as colistin, but resistance to these is already arising. One approach to combat this growing problem is the use of combination drug antibiotic adjuvant therapy, which potentiates the activity of antibiotics. Here, we review the current situation and discuss potential drug combinations that may increase the potency of antibiotics in the future. Adjuvant therapies include antibiotic combinations, synergy between antibiotics and nonantibiotics, inhibition of resistance and molecules that alter the physiology of antibiotic-insensitive cells, such as those in biofilms. We provide a rationale for these multicomponent strategies, highlighting current research and important considerations for their clinical use and pharmacological properties.
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187
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Biot FV, Valade E, Garnotel E, Chevalier J, Villard C, Thibault FM, Vidal DR, Pagès JM. Involvement of the efflux pumps in chloramphenicol selected strains of Burkholderia thailandensis: proteomic and mechanistic evidence. PLoS One 2011; 6:e16892. [PMID: 21347382 PMCID: PMC3036723 DOI: 10.1371/journal.pone.0016892] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Accepted: 01/04/2011] [Indexed: 11/18/2022] Open
Abstract
Burkholderia is a bacterial genus comprising several pathogenic species, including two species highly pathogenic for humans, B. pseudomallei and B. mallei. B. thailandensis is a weakly pathogenic species closely related to both B. pseudomallei and B. mallei. It is used as a study model. These bacteria are able to exhibit multiple resistance mechanisms towards various families of antibiotics. By sequentially plating B. thailandensis wild type strains on chloramphenicol we obtained several resistant variants. This chloramphenicol-induced resistance was associated with resistance against structurally unrelated antibiotics including quinolones and tetracyclines. We functionally and proteomically demonstrate that this multidrug resistance phenotype, identified in chloramphenicol-resistant variants, is associated with the overexpression of two different efflux pumps. These efflux pumps are able to expel antibiotics from several families, including chloramphenicol, quinolones, tetracyclines, trimethoprim and some β-lactams, and present a partial susceptibility to efflux pump inhibitors. It is thus possible that Burkholderia species can develop such adaptive resistance mechanisms in response to antibiotic pressure resulting in emergence of multidrug resistant strains. Antibiotics known to easily induce overexpression of these efflux pumps should be used with discernment in the treatment of Burkholderia infections.
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Affiliation(s)
- Fabrice V Biot
- UMR-MD-1, Facultés de Médecine et de Pharmacie, Université de la Méditerranée, IFR88, Marseille, France
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188
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Antibacterial activity of some natural products against bacteria expressing a multidrug-resistant phenotype. Int J Antimicrob Agents 2011; 37:156-61. [DOI: 10.1016/j.ijantimicag.2010.10.020] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 10/13/2010] [Accepted: 10/14/2010] [Indexed: 11/24/2022]
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189
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Rajendran R, Quinn RF, Murray C, McCulloch E, Williams C, Ramage G. Efflux pumps may play a role in tigecycline resistance in Burkholderia species. Int J Antimicrob Agents 2010; 36:151-4. [PMID: 20399621 DOI: 10.1016/j.ijantimicag.2010.03.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 03/05/2010] [Accepted: 03/08/2010] [Indexed: 11/19/2022]
Abstract
The purpose of this study was to investigate the role of multidrug resistance efflux pumps in relation to decreased susceptibility to tigecycline in clinical isolates of Burkholderia cepacia complex (BCC). The role of efflux pumps was analysed using the efflux pump inhibitor (EPI) MC-207,110. Minimum inhibitory concentrations (MICs) were determined for each strain against tigecycline alone and in the presence of 64 mg/L MC-207,110. The effect of efflux pump inhibition on the susceptibility of BCC isolates to tigecycline was assessed by a checkerboard titration assay. Ala-Nap uptake assay was performed to determine efflux pump activity in different strains. The checkerboard titration assay showed that the MIC decreased with increasing concentrations of EPI. MICs for tigecycline in the clinical isolates ranged between 8 mg/L and 32 mg/L, whereas in the presence of MC-207,110, MICs decreased significantly (range <0.125-1.0mg/L; 16 to >256 times reduction). Efflux pump activity was shown to be greatest in strains with the highest MIC and vice versa. In conclusion, BCC possess efflux pumps that influence their resistance to tigecycline. Use of an inhibitor of these pumps restored sensitivity to the antibiotic. Therefore, a combination of tigecycline and EPI to augment its efficacy may present an attractive therapeutic option.
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Affiliation(s)
- Ranjith Rajendran
- Section of Infection and Immunity, Glasgow Dental School, Faculty of Medicine, University of Glasgow, 378 Sauchiehall Street, Glasgow G2 3JZ, UK
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190
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Mahamoud A, Chevalier J, Baitiche M, Adam E, Pagès JM. An alkylaminoquinazoline restores antibiotic activity in Gram-negative resistant isolates. MICROBIOLOGY-SGM 2010; 157:566-571. [PMID: 21071494 DOI: 10.1099/mic.0.045716-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
To date, various bacterial drug efflux pump inhibitors (EPIs) have been described. They exhibit variability in their activity spectrum with respect to antibiotic structural class and bacterial species. Among the various 4-alkylaminoquinazoline derivatives synthesized and studied in this work, one molecule, 1167, increased the susceptibility of important human-pathogenic, resistant, Gram-negative bacteria towards different antibiotic classes. This 4-(3-morpholinopropylamino)-quinazoline induced an increase in the activity of chloramphenicol, nalidixic acid, norfloxacin and sparfloxacin, which are substrates of the AcrAB-TolC and MexAB-OprM efflux pumps that act in these multidrug-resistant isolates. In addition, 1167 increased the intracellular concentration of chloramphenicol in efflux pump-overproducing strains. The rate of restoration depended on the structure of the antibiotic, suggesting that different sites in the efflux pumps may be involved. A molecule exhibiting a morpholine functional group and a propyl extension of the side chain was more active.
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Affiliation(s)
- Abdallah Mahamoud
- UMR-MD-1, Facultés de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
| | - Jacqueline Chevalier
- UMR-MD-1, Facultés de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
| | - Milad Baitiche
- UMR-MD-1, Facultés de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
| | - Elissavet Adam
- UMR-MD-1, Facultés de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
| | - Jean-Marie Pagès
- UMR-MD-1, Facultés de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France
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191
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Correlation of overexpression of efflux pump genes with antibiotic resistance in Escherichia coli Strains clinically isolated from urinary tract infection patients. J Clin Microbiol 2010; 49:189-94. [PMID: 21048014 DOI: 10.1128/jcm.00827-10] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Escherichia coli is one of the most common pathogens in urinary tract infections (UTIs), and antibiotic resistance in E. coli is becoming a serious problem in treating UTI. Efflux system overexpression is reported to contribute to E. coli resistance to several antibiotics. This study investigated the correlation of antibiotic susceptibilities with the overexpression of the efflux pump genes such as marA, yhiU, yhiV, and mdfA and with risk factors for antibiotic resistance in E. coli isolated from UTI patients. We examined the expression level of efflux pump genes using quantitative real-time reverse transcription-PCR (qRT-PCR). We also tested the in vitro susceptibilities to 12 kinds of antibiotics in 64 clinical strains of E. coli isolated from UTI patients. By multivariate analyses we revealed significant relationships between the overexpression of (i) marA and MICs of cefepime (FEP) and nalidixic acid (NAL), (ii) yhiV and MICs of minocycline (MIN), and (iii) mdfA and MICs of sitafloxacin (STX). In our investigation of the efflux pump genes, risk factors such as gender and the previous use of fluoroquinolones correlated with the overexpression of marA, and indwelling catheter use correlated with the overexpression of mdfA. In conclusion, we demonstrated that the increased expression of efflux pump genes such as marA and mdfA can lead to fluoroquinolone resistance in E. coli. These results contribute to our knowledge of the efflux system and raise the possibility of developing new agents, such as efflux pump inhibitors (EPIs), to antibiotic-resistant E. coli.
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192
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Martins A, Spengler G, Martins M, Rodrigues L, Viveiros M, Davin-Regli A, Chevalier J, Couto I, Pagès JM, Amaral L. Physiological characterisation of the efflux pump system of antibiotic-susceptible and multidrug-resistant Enterobacter aerogenes. Int J Antimicrob Agents 2010; 36:313-8. [PMID: 20688487 DOI: 10.1016/j.ijantimicag.2010.06.036] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 06/13/2010] [Accepted: 06/14/2010] [Indexed: 10/19/2022]
Abstract
Enterobacter aerogenes predominates amongst Enterobacteriaceae species that are increasingly reported as producers of extended-spectrum beta-lactamases. Although this mechanism of resistance to beta-lactams is important, other mechanisms bestowing a multidrug-resistant (MDR) phenotype in this species are now well documented. Amongst these mechanisms is the overexpression of efflux pumps that extrude structurally unrelated antibiotics prior to their reaching their targets. Interestingly, although knowledge of the genetic background behind efflux pumps is rapidly advancing, few studies assess the physiological nature of the overall efflux pump system of this, or for that matter any other, bacterium. The study reported here evaluates physiologically the efflux pump system of an E. aerogenes ATCC reference as well as two strains whose MDR phenotypes are mediated by overexpressed efflux pumps. The activities of the efflux pumps in these strains are modulated by pH and glucose, although the effects of the latter are essentially restricted to pH 8, suggesting the presence of two general efflux pump systems, i.e. proton-motive force-dependent and ABC transporter types, respectively.
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Affiliation(s)
- A Martins
- Unit of Mycobacteriology, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 96, 1349-008 Lisboa, Portugal
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193
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Nallathamby PD, Lee KJ, Desai T, Xu XHN. Study of the multidrug membrane transporter of single living Pseudomonas aeruginosa cells using size-dependent plasmonic nanoparticle optical probes. Biochemistry 2010; 49:5942-53. [PMID: 20540528 PMCID: PMC2912454 DOI: 10.1021/bi100268k] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Multidrug membrane transporters (efflux pumps) in both prokaryotes and eukaryotes are responsible for impossible treatments of a wide variety of diseases, including infections and cancer, underscoring the importance of better understanding of their structures and functions for the design of effective therapies. In this study, we designed and synthesized two silver nanoparticles (Ag NPs) with average diameters of 13.1 +/- 2.5 nm (8.1-38.6 nm) and 91.0 +/- 9.3 nm (56-120 nm) and used the size-dependent plasmonic spectra of single NPs to probe the size-dependent transport kinetics of MexAB-OprM (multidrug transporter) in Pseudomonas aeruginosa in real time at nanometer resolution. We found that the level of accumulation of intracellular NPs in wild-type (WT) cells was higher than in nalB1 (overexpression of MexAB-OprM) but lower than in DeltaABM (deletion of MexAB-OprM). In the presence of proton ionophores (CCCP, inhibitor of proton motive force), we found that intracellular NPs in nalB1 were nearly doubled. These results suggest that MexAB-OprM is responsible for the extrusion of NPs out of cells and NPs (orders of magnitude larger than conventional antibiotics) are the substrates of the transporter, which indicates that the substrates may trigger the assembly of the efflux pump optimized for the extrusion of the encountered substrates. We found that the smaller NPs stayed inside the cells longer than larger NPs, suggesting the size-dependent efflux kinetics of the cells. This study shows that multisized NPs can be used to mimic various sizes of antibiotics for probing the size-dependent efflux kinetics of multidrug membrane transporters in single living cells.
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Affiliation(s)
| | - Kerry J. Lee
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529
| | - Tanvi Desai
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529
| | - Xiao-Hong Nancy Xu
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529
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Chevalier J, Mahamoud A, Baitiche M, Adam E, Viveiros M, Smarandache A, Militaru A, Pascu ML, Amaral L, Pagès JM. Quinazoline derivatives are efficient chemosensitizers of antibiotic activity in Enterobacter aerogenes, Klebsiella pneumoniae and Pseudomonas aeruginosa resistant strains. Int J Antimicrob Agents 2010; 36:164-8. [PMID: 20494558 DOI: 10.1016/j.ijantimicag.2010.03.027] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 03/29/2010] [Accepted: 03/31/2010] [Indexed: 11/25/2022]
Abstract
Amongst the three series of quinazoline derivatives synthesised and studied in this work, some molecules increase the antibiotic susceptibility of Gram-negative bacteria presenting multidrug-resistant phenotypes. N-alkyl compounds induced an increase in the activity of chloramphenicol, nalidixic acid and sparfloxacin, which are substrates of the AcrAB-TolC and MexAB-OprM efflux pumps in clinical isolates. These molecules are able to increase the intracellular concentration of chloramphenicol in efflux pump-overproducing strains. Their activity depends on the antibiotic structure, suggesting that different sites may be involved for the recognition of substrates by a given efflux pump. Quinazoline molecules exhibiting a nitro functional group are more active, and structure-activity relationship studies may be undertaken to identify the pharmacophoric group involved in the AcrB and MexB affinity sites.
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Affiliation(s)
- Jacqueline Chevalier
- UMR-MD1, Facultés de Médecine et de Pharmacie, Université de la Méditerranée, IFR88, Marseille, France
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195
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Sträuber H, Müller S. Viability states of bacteria-Specific mechanisms of selected probes. Cytometry A 2010; 77:623-34. [DOI: 10.1002/cyto.a.20920] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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196
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Subcellular Localization of Gram-Negative Bacterial Proteins Using Sparse Learning. Protein J 2010; 29:195-203. [DOI: 10.1007/s10930-010-9240-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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197
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Efflux pumps are involved in the defense of Gram-negative bacteria against the natural products isobavachalcone and diospyrone. Antimicrob Agents Chemother 2010; 54:1749-52. [PMID: 20160051 DOI: 10.1128/aac.01533-09] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The activities of two naturally occurring compounds, isobavachalcone and diospyrone, against documented strains and multidrug-resistant (MDR) Gram-negative bacterial isolates were evaluated. The results indicated that the two compounds exhibited intrinsic antibacterial activity against several Gram-negative bacteria, and their activities were significantly improved in the presence of an efflux pump inhibitor (MIC values decreased to below 10 microg/ml). In addition, the activities of isobavachalcone and diospyrone against various strains exhibiting deletions of the major efflux pump components (AcrAB, TolC) were significantly increased. The overall results indicate that isobavachalcone and diospyrone could be candidates for the development of new drugs against MDR strains and that their use in combination with efflux pump inhibitors reinforces their activity.
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198
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Blair JMA, Piddock LJV. Structure, function and inhibition of RND efflux pumps in Gram-negative bacteria: an update. Curr Opin Microbiol 2009; 12:512-9. [DOI: 10.1016/j.mib.2009.07.003] [Citation(s) in RCA: 168] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 07/02/2009] [Accepted: 07/08/2009] [Indexed: 01/07/2023]
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199
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Misra R, Bavro VN. Assembly and transport mechanism of tripartite drug efflux systems. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2009; 1794:817-25. [PMID: 19289182 DOI: 10.1016/j.bbapap.2009.02.017] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2008] [Revised: 02/21/2009] [Accepted: 02/26/2009] [Indexed: 12/30/2022]
Abstract
Multidrug efflux (MDR) pumps remove a variety of compounds from the cell into the external environment. There are five different classes of MDR pumps in bacteria, and quite often a single bacterial species expresses multiple classes of pumps. Although under normal circumstances MDR pumps confer low-level intrinsic resistance to drugs, the presence of drugs and mutations in regulatory genes lead to high level expression of MDR pumps that can pose problems with therapeutic treatments. This review focuses on the resistance nodulation cell division (RND)-class of MDR pumps that assemble from three proteins. Significant recent advancement in structural aspects of the three pump components has shed new light on the mechanism by which the tripartite efflux pumps extrude drugs. This new information will be critical in developing inhibitors against MDR pumps to improve the potency of prescribed drugs.
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Affiliation(s)
- Rajeev Misra
- Faculty of Cellular and Molecular Biosciences, School of Life Sciences, Arizona State University, Tempe, AZ 85285-4501, USA.
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200
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Pages JM, Lavigne JP, Leflon-Guibout V, Marcon E, Bert F, Noussair L, Nicolas-Chanoine MH. Efflux pump, the masked side of beta-lactam resistance in Klebsiella pneumoniae clinical isolates. PLoS One 2009; 4:e4817. [PMID: 19279676 PMCID: PMC2652100 DOI: 10.1371/journal.pone.0004817] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Accepted: 02/09/2009] [Indexed: 11/19/2022] Open
Abstract
Background β-lactamase production and porin decrease are the well-recognized mechanisms of acquired ß-lactam resistance in Klebsiella pneumoniae isolates. However, such mechanisms proved to be absent in K. pneumoniae isolates that are non susceptible to cefoxitin (FOX) and succeptible to amoxicillin+clavulanic acid in our hospital. Assessing the role of efflux pumps in this β-lactam phenotype was the aim of this study. Methodology/Findings MICs of 9 β-lactams, including cloxacillin (CLX), and other antibiotic families were tested alone and with an efflux pump inhibitor (EPI), then with both CLX (subinhibitory concentrations) and EPI against 11 unique bacteremia K. pneumoniae isolates displaying the unusual phenotype, and 2 ATCC strains. CLX and EPI-dose dependent effects were studied on 4 representatives strains. CLX MICs significantly decreased when tested with EPI. A similar phenomenon was observed with piperacillin+tazobactam whereas MICs of the other β-lactams significantly decreased only in the presence of both EPI and CLX. Thus, FOX MICs decreased 128 fold in the K. pneumoniae isolates but also16 fold in ATCC strain. Restoration of FOX activity was CLX dose-dependent suggesting a competitive relationship between CLX and the other β-lactams with regard to their efflux. For chloramphenicol, erythromycin and nalidixic acid whose resistance was also due to efflux, adding CLX to EPI did not increase their activity suggesting differences between the efflux process of these molecules and that of β-lactams. Conclusion This is the first study demonstrating that efflux mechanism plays a key role in the β-lactam susceptibility of clinical isolates of K. pneumoniae. Such data clearly evidence that the involvement of efflux pumps in ß-lactam resistance is specially underestimated in clinical isolates.
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Affiliation(s)
- Jean-Marie Pages
- UMR-MD-1, Facultés de Médecine et de Pharmacie, Université de la Méditerranée, IFR88, Marseille, France.
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