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Umar Z, Chen Q, Tang B, Xu Y, Wang J, Zhang H, Ji K, Jia X, Feng Y. The poultry pathogen Riemerella anatipestifer appears as a reservoir for Tet(X) tigecycline resistance. Environ Microbiol 2021; 23:7465-7482. [PMID: 34098588 DOI: 10.1111/1462-2920.15632] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 06/06/2021] [Indexed: 12/19/2022]
Abstract
The transferability of bacterial resistance to tigecycline, the 'last-resort' antibiotic, is an emerging challenge of global health concern. The plasmid-borne tet(X) that encodes a flavin-dependent monooxygenase represents a new mechanism for tigecycline resistance. Natural source for an ongoing family of Tet(X) resistance determinants is poorly understood. Here, we report the discovery of 26 new variants [tet(X18) to tet(X44)] from the poultry pathogen Riemerella anatipestifer, which expands extensively the current Tet(X) family. R. anatipestifer appears as a natural reservoir for tet(X), of which the chromosome harbours varied copies of tet(X) progenitors. Despite that an inactive ancestor rarely occurs, the action and mechanism of Tet(X2/4)-P, a putative Tet(X) progenitor, was comprehensively characterized, giving an intermediate level of tigecycline resistance. The potential pattern of Tet(X) dissemination from ducks to other animals and humans was raised, in the viewpoint of ecological niches. Therefore, this finding defines a large pool of natural sources for Tet(X) tigecycline resistance, heightening the need of efficient approaches to manage the inter-species transmission of tet(X) resistance determinants.
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Affiliation(s)
- Zeeshan Umar
- Department of Pathogen Biology & Microbiology and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China.,College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Qiwei Chen
- Department of Pathogen Biology & Microbiology and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China.,State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, 730046, China
| | - Biao Tang
- Department of Pathogen Biology & Microbiology and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China.,State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products & Institute of Quality and Standard for Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang, 310021, China
| | - Yongchang Xu
- Department of Pathogen Biology & Microbiology and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China.,College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Jinzi Wang
- Guangxi Key Laboratory of Utilization of Microbial and Botanical Resources & Guangxi Key Laboratory for Polysaccharide Materials and Modifications, School of Marine Sciences and Biotechnology, Guangxi University for Nationalities, Nanning, Guangxi, 530008, China
| | - Huimin Zhang
- Department of Pathogen Biology & Microbiology and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China.,Cancer Center at Illinois, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Kai Ji
- Department of Pathogen Biology & Microbiology and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China
| | - Xu Jia
- Non-coding RNA and Drug Discovery Key Laboratory of Sichuan Province, Chengdu Medical College, Chengdu, Sichuan, 610500, China
| | - Youjun Feng
- Department of Pathogen Biology & Microbiology and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China.,College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.,Non-coding RNA and Drug Discovery Key Laboratory of Sichuan Province, Chengdu Medical College, Chengdu, Sichuan, 610500, China
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Enhancement of the antibiotic activity by quercetin against Staphylococcus aureus efflux pumps. J Bioenerg Biomembr 2021; 53:157-167. [PMID: 33683535 DOI: 10.1007/s10863-021-09886-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 02/25/2021] [Indexed: 10/22/2022]
Abstract
The objective of this work was to evaluate the inhibitory effect of quercetin on S. aureus Efflux Pumps. The MIC of Quercetin was evaluated through the broth microdilution method, as well as the Efflux Pump inhibition assay through the method of reducing the antibiotic minimum inhibitory concentration as well as that of ethidium bromide. The in silico approach through bioinformatics was performed to demonstrate the molecular mechanism of interaction of the substrate and the binding cavity. The Quercetin inhibition concentration was not clinically relevant. With respect to the reversal of bacterial resistance effect by efflux pump inhibition, this effect was observed with the strains carrying the TetK and NorA pumps. Regarding the interaction between the Quercetin complex and the NorA pump, the extra stability was provided by hydrogen bonds produced by the hydroxyl group.
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dos Santos JF, Tintino SR, de Freitas TS, Campina FF, de A. Menezes IR, Siqueira-Júnior JP, Coutinho HD, Cunha FA. In vitro e in silico evaluation of the inhibition of Staphylococcus aureus efflux pumps by caffeic and gallic acid. Comp Immunol Microbiol Infect Dis 2018; 57:22-28. [DOI: 10.1016/j.cimid.2018.03.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Accepted: 03/05/2018] [Indexed: 02/07/2023]
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Lekshmi M, Ammini P, Adjei J, Sanford LM, Shrestha U, Kumar S, Varela MF. Modulation of antimicrobial efflux pumps of the major facilitator superfamily in Staphylococcus aureus. AIMS Microbiol 2018; 4:1-18. [PMID: 31294201 PMCID: PMC6605029 DOI: 10.3934/microbiol.2018.1.1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 12/19/2017] [Indexed: 12/15/2022] Open
Abstract
Variants of the microorganism Staphylococcus aureus which are resistant to antimicrobial agents exist as causative agents of serious infectious disease and constitute a considerable public health concern. One of the main antimicrobial resistance mechanisms harbored by S. aureus pathogens is exemplified by integral membrane transport systems that actively remove antimicrobial agents from bacteria where the cytoplasmic drug targets reside, thus allowing the bacteria to survive and grow. An important class of solute transporter proteins, called the major facilitator superfamily, includes related and homologous passive and secondary active transport systems, many of which are antimicrobial efflux pumps. Transporters of the major facilitator superfamily, which confer antimicrobial efflux and bacterial resistance in S. aureus, are good targets for development of resistance-modifying agents, such as efflux pump inhibition. Such modulatory action upon these antimicrobial efflux systems of the major facilitator superfamily in S. aureus may circumvent resistance and restore the clinical efficacy of therapy towards S. aureus infection.
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Affiliation(s)
- Manjusha Lekshmi
- QC Laboratory, Harvest and Post Harvest Technology Division, ICAR-Central Institute of Fisheries Education (CIFE), Seven Bungalows, Versova, Andheri (W), Mumbai, 400061, India
| | - Parvathi Ammini
- CSIR-National Institute of Oceanography (NIO), Regional Centre, Dr. Salim Ali Road, Kochi, 682018, India
| | - Jones Adjei
- Eastern New Mexico, Department of Biology, Station 33, 1500 South Avenue K, Portales, NM, 88130, USA
| | - Leslie M Sanford
- Eastern New Mexico, Department of Biology, Station 33, 1500 South Avenue K, Portales, NM, 88130, USA
| | - Ugina Shrestha
- Eastern New Mexico, Department of Biology, Station 33, 1500 South Avenue K, Portales, NM, 88130, USA
| | - Sanath Kumar
- QC Laboratory, Harvest and Post Harvest Technology Division, ICAR-Central Institute of Fisheries Education (CIFE), Seven Bungalows, Versova, Andheri (W), Mumbai, 400061, India
| | - Manuel F Varela
- Eastern New Mexico, Department of Biology, Station 33, 1500 South Avenue K, Portales, NM, 88130, USA
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Tintino SR, Morais-Tintino CD, Campina FF, Costa MDS, Menezes IR, de Matos YML, Calixto-Júnior JT, Pereira PS, Siqueira-Junior JP, Leal-Balbino TC, Coutinho HD, Balbino VQ. Tannic acid affects the phenotype of Staphylococcus aureus resistant to tetracycline and erythromycin by inhibition of efflux pumps. Bioorg Chem 2017; 74:197-200. [DOI: 10.1016/j.bioorg.2017.08.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 08/07/2017] [Accepted: 08/11/2017] [Indexed: 10/19/2022]
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Tintino SR, Oliveira-Tintino CD, Campina FF, Silva RL, Costa MDS, Menezes IR, Calixto-Júnior JT, Siqueira-Junior JP, Coutinho HD, Leal-Balbino TC, Balbino VQ. Evaluation of the tannic acid inhibitory effect against the NorA efflux pump of Staphylococcus aureus. Microb Pathog 2016; 97:9-13. [DOI: 10.1016/j.micpath.2016.04.003] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Revised: 03/30/2016] [Accepted: 04/01/2016] [Indexed: 01/11/2023]
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Schweizer HP. Understanding efflux in Gram-negative bacteria: opportunities for drug discovery. Expert Opin Drug Discov 2012; 7:633-42. [PMID: 22607346 DOI: 10.1517/17460441.2012.688949] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION Bacteria evolved an arsenal of mechanisms to deal with toxic compounds and metabolic stresses, including antimicrobial agents. Efflux pumps are major players in the multidrug resistance of Gram-negative bacteria and pose major hurdles in the drug discovery process. However, recent advances in our understanding of efflux in these bacteria provide opportunities and assets for drug discovery. AREAS COVERED This review provides an overview of drug efflux in Gram-negative bacteria and its role in antimicrobial resistance, stress responses and other biological processes such as biofilm formation, and virulence. The discussion includes comments on the significance of synergy between a low-permeability outer membrane and efflux, notably the role of porins and lipopolysaccharide. The author then summarizes efforts aimed at inhibiting efflux pumps as a means to extend the utility of clinically useful antibiotics. This includes highlights of identification and characterization of small molecule efflux pump inhibitors (EPIs) from natural and synthetic sources, as well as novel strategies such as gene silencing and inhibitory antibodies. EXPERT OPINION Options for treating infections caused by multidrug-resistant bacteria are limited. Given the attractiveness of the therapeutic potential of efflux pump inhibition, further studies exploring novel strategies to interfere with efflux pump expression and function are warranted. This includes rational EPI design facilitated by pump structure information, exploitation of genetically defined efflux-proficient and efflux-compromised strain panels and non-traditional approaches such as pump inhibition by gene silencing, antibodies and perhaps even phage.
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Affiliation(s)
- Herbert P Schweizer
- Colorado State University, IDRC at Foothills Campus, Department of Microbiology, Immunology and Pathology, Fort Collins, CO 80523-0922, USA.
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Marquez B. Bacterial efflux systems and efflux pumps inhibitors. Biochimie 2006; 87:1137-47. [PMID: 15951096 DOI: 10.1016/j.biochi.2005.04.012] [Citation(s) in RCA: 175] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2005] [Accepted: 04/25/2005] [Indexed: 10/25/2022]
Abstract
It is now well established that bacterial resistance to antibiotics has become a serious problem of public health that concerns almost all antibacterial agents and that manifests in all fields of their application. Among the three main mechanisms involved in bacterial resistance (target modification, antibiotic inactivation or default of its accumulation within the cell), efflux pumps, responsible for the extrusion of the antibiotic outside the cell, have recently received a particular attention. Actually, these systems, classified into five families, can confer resistance to a specific class of antibiotics or to a large number of drugs, thus conferring a multi-drug resistance (MDR) phenotype to bacteria. To face this issue, it is urgent to find new molecules active against resistant bacteria. Among the strategies employed, the search for inhibitors of resistance mechanisms seems to be attractive because such molecules could restore antibiotic activity. In the case of efflux systems, efflux pump inhibitors (EPIs) are expected to block the pumps and such EPIs, if active against MDR pumps, would be of great interest. This review will focus on the families of bacterial efflux systems conferring drug resistance, and on the EPIs that have been identified to restore antibiotic activity.
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Affiliation(s)
- Béatrice Marquez
- UMR CNRS 7573 - ENSCP, Laboratoire de Biochimie, 11, rue Pierre-et-Marie-Curie, 75005 Paris, France.
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Kaatz GW. Inhibition of bacterial efflux pumps: a new strategy to combat increasing antimicrobial agent resistance. Expert Opin Emerg Drugs 2005; 7:223-33. [PMID: 15989546 DOI: 10.1517/14728214.7.2.223] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Resistance to multiple drugs in medically important bacteria results in therapeutic challenges for the clinician. The mechanisms by which bacteria evade the effects of antimicrobial agents are many, but in recent years it has become apparent that efflux is a significant means of resistance and probably explains the intrinsic resistance to numerous drugs observed in species such as Pseudomonas aeruginosa. Drug efflux is mediated by membrane-based hydrophobic proteins belonging to several distinct families, the members of which are related by structural characteristics, mechanism of action and energy source for the transport process. The multi-drug efflux transporters are particularly problematic as they are capable of extruding numerous structurally dissimilar drugs. Inhibition of these pumps, and even those with more limited substrate specificity, has been shown to decrease intrinsic resistance, reverse acquired resistance and reduce the emergence of mutants with higher-level target-based mutational resistance. Combining broad spectrum efflux pump inhibitors with current drugs that are pump substrates can recover clinically relevant activity of those compounds and thus may reduce the need for the discovery and development of new antimicrobial agents that are not pump substrates. Additional effort toward the identification, characterisation and determination of the clinical utility of efflux pump inhibitors is warranted.
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Affiliation(s)
- Glenn W Kaatz
- School of Medicine and College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA.
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Abstract
Drug resistance in bacteria, and especially resistance to multiple antibacterials, has attracted much attention in recent years. In addition to the well known mechanisms, such as inactivation of drugs and alteration of targets, active efflux is now known to play a major role in the resistance of many species to antibacterials. Drug-specific efflux (e.g. that of tetracycline) has been recognised as the major mechanism of resistance to this drug in Gram-negative bacteria. In addition, we now recognise that multidrug efflux pumps are becoming increasingly important. Such pumps play major roles in the antiseptic resistance of Staphylococcus aureus, and fluoroquinolone resistance of S. aureus and Streptococcus pneumoniae. Multidrug pumps, often with very wide substrate specificity, are not only essential for the intrinsic resistance of many Gram-negative bacteria but also produce elevated levels of resistance when overexpressed. Paradoxically, 'advanced' agents for which resistance is unlikely to be caused by traditional mechanisms, such as fluoroquinolones and beta-lactams of the latest generations, are likely to select for overproduction mutants of these pumps and make the bacteria resistant in one step to practically all classes of antibacterial agents. Such overproduction mutants are also selected for by the use of antiseptics and biocides, increasingly incorporated into consumer products, and this is also of major concern. We can consider efflux pumps as potentially effective antibacterial targets. Inhibition of efflux pumps by an efflux pump inhibitor would restore the activity of an agent subject to efflux. An alternative approach is to develop antibacterials that would bypass the action of efflux pumps.
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Affiliation(s)
- Xian-Zhi Li
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202, USA
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11
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Chopra I. New developments in tetracycline antibiotics: glycylcyclines and tetracycline efflux pump inhibitors. Drug Resist Updat 2002; 5:119-25. [PMID: 12237079 DOI: 10.1016/s1368-7646(02)00051-1] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The tetracyclines, discovered in the 1940s, are a well-established class of antibiotics that still have a role in treating microbial infections in man. However, the widespread emergence of bacterial resistance due to efflux and ribosomal protection mechanisms has severely limited their effectiveness. A new generation of tetracyclines, the glycylcyclines, has been developed to overcome resistance to earlier tetracyclines. One of the new glycylcyclines, 9-t-butylglyclamido-minocycline (GAR-936, tigecycline) is currently undergoing clinical trials. This review considers the current status of glycylcyclines and the possibility that resistance to these agents might arise in the future. Other approaches are also being taken to address the emergence of resistance to tetracyclines. Recently, a number of tetracycline efflux pump inhibitors have been discovered that might be used in combination with earlier tetracyclines to restore their activity against resistant organisms. However, the development of tetracycline efflux pump inhibitors is complicated by the occurrence of several efflux pump sub-families and by the presence of both efflux and ribosomal protection mechanisms in the same organism, especially in naturally occurring, Gram-positive clinical isolates.
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Affiliation(s)
- Ian Chopra
- Antimicrobial Research Centre and Division of Microbiology, School of Biochemistry and Molecular Biology, University of Leeds, UK.
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12
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Hansen LH, Sørensen SJ. Detection and quantification of tetracyclines by whole cell biosensors. FEMS Microbiol Lett 2000; 190:273-8. [PMID: 11034291 DOI: 10.1111/j.1574-6968.2000.tb09298.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Three different mini-Tn5 plasmids, containing a tetracycline-inducible promoter, Ptet and a regulatory gene, tetR, in operon fusions with a reporter gene system (lacZYA, luxCDABE or gfp), were constructed. These biosensor constructs responded to low levels of tetracyclines by producing beta-galactosidase, light or green fluorescent protein. They did so in a quantitative manner, thus enabling the quantification of tetracyclines in the immediate surroundings of the biosensor organism. All three constructs were transferred successfully to different gram-negative bacteria by conjugation. An Escherichia coli strain containing the Ptet-lac construct was used to determine oxytetracycline in milk as a demonstration of the application of these biosensors.
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Affiliation(s)
- L H Hansen
- Department of General Microbiology, University of Copenhagen, Denmark
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Russell AD. Mechanisms of bacterial resistance to antibiotics and biocides. PROGRESS IN MEDICINAL CHEMISTRY 2000; 35:133-97. [PMID: 10795401 DOI: 10.1016/s0079-6468(08)70036-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- A D Russell
- Welsh School of Pharmacy, University of Wales, Cardiff, UK
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Renau TE, Léger R, Flamme EM, Sangalang J, She MW, Yen R, Gannon CL, Griffith D, Chamberland S, Lomovskaya O, Hecker SJ, Lee VJ, Ohta T, Nakayama K. Inhibitors of efflux pumps in Pseudomonas aeruginosa potentiate the activity of the fluoroquinolone antibacterial levofloxacin. J Med Chem 1999; 42:4928-31. [PMID: 10585202 DOI: 10.1021/jm9904598] [Citation(s) in RCA: 186] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- T E Renau
- Microcide Pharmaceuticals Inc., 850 Maude Avenue, Mountain View, California 94043, USA.
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Salam MA. Antimicrobial therapy for shigellosis: issues on antimicrobial resistance. JAPANESE JOURNAL OF MEDICAL SCIENCE & BIOLOGY 1999; 51 Suppl:S43-62. [PMID: 10211436 DOI: 10.7883/yoken1952.51.supplement1_s43] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- M A Salam
- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
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16
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Antimicrobial Potentiation Approaches: Targets and Inhibitors. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 1998. [DOI: 10.1016/s0065-7743(08)61077-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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17
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Hirata T, Wakatabe R, Nielsen J, Someya Y, Fujihira E, Kimura T, Yamaguchi A. A novel compound, 1,1-dimethyl-5(1-hydroxypropyl)-4,6,7-trimethylindan, is an effective inhibitor of the tet(K) gene-encoded metal-tetracycline/H+ antiporter of Staphylococcus aureus. FEBS Lett 1997; 412:337-40. [PMID: 9256247 DOI: 10.1016/s0014-5793(97)00796-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A novel indan derivative, 1,1-dimethyl-5-(1-hydroxypropyl)-4,6,7-trimethylindan (Ro 07-3149), was found to be a strong inhibitor of the tet(K) gene-encoded tetracycline/H+ antiporter of Staphylococcus aureus. One micromole of this compound per mg membrane protein was enough for complete inhibition of the Tet(K)-mediated tetracycline transport and tetracycline-coupled proton transport, without the energy state of the membrane being affected. The mode of inhibition was non-competitive. Although this compound caused membrane de-energization at a high concentration, the IC50 value for de-energization (7.3 micromol/mg membrane protein) was about 17 times and 33 times higher than the values for Tet(K)-mediated proton/tetracycline antiport and [3H]tetracycline transport, respectively, indicating that the inhibitory action of Ro 07-3149 is not due to the uncoupling effect of the inhibitor.
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Affiliation(s)
- T Hirata
- Department of Cell Membrane Biology, Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Japan
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Abstract
Over the past five years, concerns have heightened over the escalating numbers of pathogenic micro-organisms isolated that are resistant to many antibiotics and drugs. This phenomenon poses major problems in the treatment of patients with hospital- or community-acquired infections caused by bacteria, fungi, or parasitic organisms. Microbial cells have acquired resistances to specific antibiotics and drugs by mechanisms that include antibiotic inactivation, target alteration, or drug exclusion. More recently, the importance of another mechanism, that of drug expulsion, has been recognized as contributing significantly to antibiotic and drug resistance in microbes. Drug expulsion, mediated by membrane-associated drug efflux pumps, can protect cells from a range of toxic compounds and therefore may confer single-step multidrug resistance. It is imperative that new drugs be designed or discovered that will poison the pumps or bypass the efflux mechanisms.
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Affiliation(s)
- H F Jenkinson
- Nuffield Department of Clinical Biochemistry, University of Oxford, John Radcliffe Hospital, United Kingdom
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Gardner KJ, Cunliffe WJ, Eady EA, Cove JH. Variation in comedonal antibiotic concentrations following application of topical tetracycline for acne vulgaris. Br J Dermatol 1994; 131:649-54. [PMID: 7999595 DOI: 10.1111/j.1365-2133.1994.tb04976.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A miniaturized sensitive bioassay was used to detect tetracycline in open comedones following topical twice daily application of 0.22% tetracycline hydrochloride for a minimum of 4 weeks to the facial skin of patients with mild to moderate acne. The lower limit of detection was 4.8 +/- 0.8 ng per comedone or per 10 microliters. Using this method, 111 of 155 open comedones from 15 patients were found to contain a detectable amount of tetracycline, ranging from 1.8 to 156.9 ng per comedone, and between 4.5 and 1140.1 ng per mg comedonal material. There was a significant effect of comedone weight on tetracycline content, with smaller comedones containing proportionately more tetracycline. The Spearman rank correlation coefficient was -0.5619 (P < 0.001). All 111 comedones in which tetracycline was detected contained sufficient drug to inhibit fully antibiotic-sensitive propionibacteria. However, conditions favourable to the selection and overgrowth of highly tetracycline-resistant strains (MIC > or = 32 micrograms/ml) prevailed in at least 18.7% (29 of 155) of the comedones tested.
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Affiliation(s)
- K J Gardner
- Department of Dermatology, Leeds General Infirmary, U.K
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