51
|
Lashinsky JN, Henig O, Pogue JM, Kaye KS. Minocycline for the Treatment of Multidrug and Extensively Drug-Resistant A. baumannii: A Review. Infect Dis Ther 2017; 6:199-211. [PMID: 28357705 PMCID: PMC5446366 DOI: 10.1007/s40121-017-0153-2] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Indexed: 11/28/2022] Open
Abstract
Acinetobacter baumannii can cause life-threatening nosocomial infections associated with high rates of morbidity and mortality. In recent years, the increasing number of infections due to extensively drug-resistant Acinetobacter with limited treatment options has resulted in a need for additional therapeutic agents, and a renaissance of older, neglected antimicrobials. This has led to an increased interest in the use of minocycline to treat these infections. Minocycline has been shown to overcome many resistance mechanisms affecting other tetracyclines in A. baumannii, including tigecycline. Additionally, it has favorable pharmacokinetic and pharmacodynamic properties, as well as excellent in vitro activity against drug-resistant A. baumannii. Available data support therapeutic success with minocycline, while ease of dosing with no need for renal or hepatic dose adjustments and improved safety have made it an appealing therapy. This review will focus on the mechanisms of action and resistance to tetracyclines in A. baumannii, the in vitro activity, pharmacokinetic and pharmacodynamic properties of minocycline against A. baumannii, and finally the clinical experience with minocycline for the treatment of invasive infections due to this pathogen.
Collapse
Affiliation(s)
| | - Oryan Henig
- Department of Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Jason M Pogue
- Department of Pharmacy Services, Sinai-Grace Hospital, Detroit Medical Center, Detroit, MI, USA
- Wayne State University School of Medicine, Detroit, MI, USA
| | - Keith S Kaye
- Department of Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| |
Collapse
|
52
|
Otero F, Gosálvez J, Bou G, Fernández JL. Simple and Fast Detection of Resistance to Antibiotic Inhibitors of Protein Synthesis in Gram-Negative Pathogens Through Evaluation of Mitomycin C-Induced Cell Elongation. Microb Drug Resist 2017; 23:973-981. [PMID: 28467172 DOI: 10.1089/mdr.2017.0028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Increasing the resistance of Gram-negative pathogens to antibiotics that inhibit protein synthesis is of great concern. In life-threatening situations, an early detection of antibiotic resistance may improve patient outcome. A rapid assay for the identification of antibiotic resistance to gentamicin, tobramycin, and tigecycline has been designed and tested in clinical strains of Acinetobacter baumannii, Pseudomonas aeruginosa, and the Enterobacteriaceae Escherichia coli and Klebsiella pneumoniae. Exponentially growing cultures were incubated with 0.5 mg/L mitomycin C (MMC) for 2 hr (10 mg/L for A. baumannii), which induced significant cell enlargement as visualized under the microscope. Addition of the appropriate antibiotic dose 15 min before the addition of MMC prevented elongation when the strain was susceptible to the antibiotic, thereby inhibiting protein synthesis. Cell enlargement was not precluded in the antibiotic resistant strains, where protein synthesis had not been successfully inhibited. In comparison with the standard dilution-based antibiogram, the sensitivity of the assay was 100% and the specificity ranged between 96.0% and 100%. Results were obtained after 2 hr and 45 min from exponentially growing cultures. The procedure is easy, reliable, and demonstrates the suitability of the evaluation of simple morphological changes, which are protein synthesis dependent, for the rapid detection of antibiotic resistance.
Collapse
Affiliation(s)
- Fátima Otero
- 1 Unidad de Genética, Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC) , Sergas, Universidade da Coruña (UDC), Spain .,2 Laboratorio de Genética, Centro Oncológico de Galicia , A Coruña, Spain
| | - Jaime Gosálvez
- 3 Unidad de Genética, Facultad de Biología, Universidad Autónoma de Madrid , Madrid, Spain
| | - Germán Bou
- 4 Servicio de Microbiología, Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC) , Sergas, Universidade da Coruña (UDC), Spain
| | - José Luis Fernández
- 1 Unidad de Genética, Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC) , Sergas, Universidade da Coruña (UDC), Spain .,2 Laboratorio de Genética, Centro Oncológico de Galicia , A Coruña, Spain
| |
Collapse
|
53
|
Deng Y, Sun C, Hunt DK, Fyfe C, Chen CL, Grossman TH, Sutcliffe JA, Xiao XY. Heterocyclyl Tetracyclines. 1. 7-Trifluoromethyl-8-Pyrrolidinyltetracyclines: Potent, Broad Spectrum Antibacterial Agents with Enhanced Activity against Pseudomonas aeruginosa. J Med Chem 2017; 60:2498-2512. [DOI: 10.1021/acs.jmedchem.6b01903] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Yonghong Deng
- Discovery
Chemistry, ‡Microbiology, Tetraphase Pharmaceuticals, 480
Arsenal Way, Watertown, Massachusetts 02472, United States
| | - Cuixiang Sun
- Discovery
Chemistry, ‡Microbiology, Tetraphase Pharmaceuticals, 480
Arsenal Way, Watertown, Massachusetts 02472, United States
| | - Diana K. Hunt
- Discovery
Chemistry, ‡Microbiology, Tetraphase Pharmaceuticals, 480
Arsenal Way, Watertown, Massachusetts 02472, United States
| | - Corey Fyfe
- Discovery
Chemistry, ‡Microbiology, Tetraphase Pharmaceuticals, 480
Arsenal Way, Watertown, Massachusetts 02472, United States
| | - Chi-Li Chen
- Discovery
Chemistry, ‡Microbiology, Tetraphase Pharmaceuticals, 480
Arsenal Way, Watertown, Massachusetts 02472, United States
| | - Trudy H. Grossman
- Discovery
Chemistry, ‡Microbiology, Tetraphase Pharmaceuticals, 480
Arsenal Way, Watertown, Massachusetts 02472, United States
| | - Joyce A. Sutcliffe
- Discovery
Chemistry, ‡Microbiology, Tetraphase Pharmaceuticals, 480
Arsenal Way, Watertown, Massachusetts 02472, United States
| | - Xiao-Yi Xiao
- Discovery
Chemistry, ‡Microbiology, Tetraphase Pharmaceuticals, 480
Arsenal Way, Watertown, Massachusetts 02472, United States
| |
Collapse
|
54
|
Viola GM, Rosenblatt J, Raad II. Drug eluting antimicrobial vascular catheters: Progress and promise. Adv Drug Deliv Rev 2017; 112:35-47. [PMID: 27496702 DOI: 10.1016/j.addr.2016.07.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 06/14/2016] [Accepted: 07/26/2016] [Indexed: 12/13/2022]
Abstract
Vascular catheters are critical tools in modern healthcare yet present substantial risks of serious bloodstream infections that exact significant health and economic burdens. Drug-eluting antimicrobial vascular catheters have become important tools in preventing catheter-related bloodstream infections and their importance is expected to increase as significant initiatives are expanded to eliminate and make the occurrence of these infections unacceptable. Here we review clinically significant and emerging drug-eluting antimicrobial catheters within the categories of antibiotic, antiseptic, novel bioactive agents and energy-enhanced drug eluting antimicrobial catheters. Important representatives of each category are reviewed from the standpoints of mechanisms of action, physical-chemical properties, safety, in vitro and clinical effectiveness.
Collapse
Affiliation(s)
- George M Viola
- Department of Infectious Diseases, Infection Control, and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Joel Rosenblatt
- Department of Infectious Diseases, Infection Control, and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Issam I Raad
- Department of Infectious Diseases, Infection Control, and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| |
Collapse
|
55
|
Tigecycline Nonsusceptibility Occurs Exclusively in Fluoroquinolone-Resistant Escherichia coli Clinical Isolates, Including the Major Multidrug-Resistant Lineages O25b:H4-ST131-H30R and O1-ST648. Antimicrob Agents Chemother 2017; 61:AAC.01654-16. [PMID: 27855067 DOI: 10.1128/aac.01654-16] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 11/08/2016] [Indexed: 11/20/2022] Open
Abstract
Tigecycline (TGC) is a last-line drug for multidrug-resistant Enterobacteriaceae We investigated the mechanism(s) underlying TGC nonsusceptibility (TGC resistant/intermediate) in Escherichia coli clinical isolates. The MIC of TGC was determined for 277 fluoroquinolone-susceptible isolates (ciprofloxacin [CIP] MIC, <0.125 mg/liter) and 194 fluoroquinolone-resistant isolates (CIP MIC, >2 mg/liter). The MIC50 and MIC90 for TGC in fluoroquinolone-resistant isolates were 2-fold higher than those in fluoroquinolone-susceptible isolates (MIC50, 0.5 mg/liter versus 0.25 mg/liter; MIC90, 1 mg/liter versus 0.5 mg/liter, respectively). Two fluoroquinolone-resistant isolates (O25b:H4-ST131-H30R and O125:H37-ST48) were TGC resistant (MICs of 4 and 16 mg/liter, respectively), and four other isolates of O25b:H4-ST131-H30R and an isolate of O1-ST648 showed an intermediate interpretation (MIC, 2 mg/liter). No TGC-resistant/intermediate strains were found among the fluoroquinolone-susceptible isolates. The TGC-resistant/intermediate isolates expressed higher levels of acrA and acrB and had lower intracellular TGC concentrations than susceptible isolates, and they possessed mutations in acrR and/or marR The MICs of acrAB-deficient mutants were markedly lower (0.25 mg/liter) than those of the parental strain. After continuous stepwise exposure to CIP in vitro, six of eight TGC-susceptible isolates had reduced TGC susceptibility. Two of them acquired TGC resistance (TGC MIC, 4 mg/liter) and exhibited expression of acrA and acrB and mutations in acrR and/or marR In conclusion, a population of fluoroquinolone-resistant E. coli isolates, including major extraintestinal pathogenic lineages O25b:H4-ST131-H30R and O1-ST648, showed reduced susceptibility to TGC due to overexpression of the efflux pump AcrAB-TolC, leading to decreased intracellular concentrations of the antibiotics that may be associated with the development of fluoroquinolone resistance.
Collapse
|
56
|
Tan J, Song M, Zhou M, Hu Y. Antibiotic tigecycline enhances cisplatin activity against human hepatocellular carcinoma through inducing mitochondrial dysfunction and oxidative damage. Biochem Biophys Res Commun 2017; 483:17-23. [PMID: 28069382 DOI: 10.1016/j.bbrc.2017.01.021] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 01/05/2017] [Indexed: 01/08/2023]
Abstract
Targeting mitochondrial metabolism has been recently demonstrated to be a promising therapeutic strategy for the treatment of various cancer. In this work, we demonstrate that antibiotic tigecycline is selectively against hepatocellular carcinoma (HCC) through inducing mitochondrial dysfunction and oxidative damage. Tigecycline is more effective in inhibiting proliferation and inducing apoptosis of HCC than normal liver cells. Importantly, tigecycline significantly enhances the inhibitory effects of chemotherapeutic drug cisplatin in HCC in vitro and in vivo. Mechanistically, tigecycline specifically inhibits mitochondrial translation as shown by the decreased protein levels of Cox-1 and -2 but not Cox-4 or Grp78, and increased mRNA levels of Cox-1 and -2 but not Cox-4 in HCC cells exposed to tigecycline. In addition, tigecycline significantly induces mitochondrial dysfunction in HCC cells via decreasing mitochondrial membrane potential, complex I and IV activities, mitochondrial respiration and ATP levels. Tigecycline also increases levels of mitochondrial superoxide, hydrogen peroxide and ROS levels. Consistent with oxidative stress, oxidative damage on DNA, protein and lipid are also observed in tigecycline-treated cells. Importantly, antioxidant N-acetyl-l-cysteine (NAC) reverses the effects of tigecycline, suggesting that oxidative stress is required for the action of tigecycline in HCC cells. We further show that HCC cells have higher level of mitochondrial biogenesis than normal liver cells which might explain the different sensitivity to tigecycline between HCC and normal liver cells. Our work is the first to demonstrate that tigecycline is a promising candidate for HCC treatment and highlight the therapeutic value of targeting mitochondrial metabolism in HCC.
Collapse
Affiliation(s)
- Jun Tan
- Department of Hepatology, Ningbo No. 2 Hospital, Ningbo, 315010, China
| | - Meijun Song
- Department of Respiratory Medicine, Ningbo Medical Treatment Center Li Huili Hospital, Ningbo, 315041, China
| | - Mi Zhou
- School of Medicine, Ningbo University, Ningbo, 315211, China.
| | - Yaoren Hu
- Department of Hepatology, Ningbo No. 2 Hospital, Ningbo, 315010, China.
| |
Collapse
|
57
|
|
58
|
Reynolds LJ, Roberts AP, Anjum MF. Efflux in the Oral Metagenome: The Discovery of a Novel Tetracycline and Tigecycline ABC Transporter. Front Microbiol 2016; 7:1923. [PMID: 27999567 PMCID: PMC5138185 DOI: 10.3389/fmicb.2016.01923] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Accepted: 11/16/2016] [Indexed: 01/07/2023] Open
Abstract
Antibiotic resistance in human bacterial pathogens and commensals is threatening our ability to treat infections and conduct common medical procedures. As novel antibiotics are discovered and marketed it is important that we understand how resistance to them may arise and know what environments may act as reservoirs for such resistance genes. In this study a tetracycline and tigecycline resistant clone was identified by screening a human saliva metagenomic library in Escherichia coli EPI300 on agar containing 5 μg/ml tetracycline. Sequencing of the DNA insert present within the tetracycline resistant clone revealed it to contain a 7,765 bp fragment harboring novel ABC half transporter genes, tetAB(60). Mutagenesis studies performed on these genes confirmed that they were responsible for the tetracycline and tigecycline resistance phenotypes. Growth studies performed using E. coli EPI300 clones that harbored either the wild type, the mutated, or none of these genes indicated that there was a fitness cost associated with presence of these genes, with the isolate harboring both genes exhibiting a significantly slower growth than control strains. Given the emergence of E. coli strains that are sensitive only to tigecycline and doxycycline it is concerning that such a resistance mechanism has been identified in the human oral cavity.
Collapse
Affiliation(s)
- Liam J Reynolds
- Department of Microbial Diseases, UCL Eastman Dental Institute, Faculty of Medical Sciences, University College LondonLondon, UK; Department of Bacteriology, Animal and Plant Health AgencyAddlestone, UK
| | - Adam P Roberts
- Department of Microbial Diseases, UCL Eastman Dental Institute, Faculty of Medical Sciences, University College London London, UK
| | - Muna F Anjum
- Department of Microbial Diseases, UCL Eastman Dental Institute, Faculty of Medical Sciences, University College LondonLondon, UK; Department of Bacteriology, Animal and Plant Health AgencyAddlestone, UK
| |
Collapse
|
59
|
Tigecycline Therapy for Nosocomial Pneumonia due to Carbapenem-Resistant Gram-Negative Bacteria in Critically Ill Patients Who Received Inappropriate Initial Antibiotic Treatment: A Retrospective Case Study. BIOMED RESEARCH INTERNATIONAL 2016; 2016:8395268. [PMID: 28044137 PMCID: PMC5164885 DOI: 10.1155/2016/8395268] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 11/09/2016] [Accepted: 11/14/2016] [Indexed: 02/01/2023]
Abstract
Background. Nosocomial pneumonia due to carbapenem-resistant Gram-negative bacteria (CRGNB) is a growing concern because treatment options are limited and the mortality rate is high. The effect of tigecycline (TGC) on nosocomial pneumonia due to CRGNB in patients who have received inappropriate initial empiric antibiotic treatment (IIAT) is unclear. Therefore, this study aimed to examine the effect of TGC on nosocomial pneumonia due to CRGNB in critically ill patients who had received IIAT. Methods. A retrospective study was conducted in an adult respiratory intensive care unit. Data were obtained and analyzed for all patients who were treated with TGC ≥ 3 days for microbiologically confirmed nosocomial pneumonia due to CRGNB and had experienced initial antibiotic failure. Clinical and microbiological outcomes were investigated. Results. Thirty-one patients with hospital-acquired pneumonia or ventilator-associated pneumonia were included in the study. The majority of the responsible organisms were carbapenem-resistant Acinetobacter baumannii (67.7%), followed by Klebsiella pneumoniae (16.1%) and Escherichia coli (9.7%). Twenty patients were treated with high-dose TGC therapy (100 mg every 12 h after a 200 mg loading dose), and the others received a standard-dose therapy (50 mg every 12 h after a 100 mg loading dose). The duration of TGC therapy was 14.3 ± 2.8 days. The global clinical cure rate and the microbiological eradication rate were 48.4% and 61.3%, respectively. The overall ICU mortality rate was 45.2%. A higher score on the Acute Physiology and Chronic Health Evaluation II and a longer duration of IIAT were associated with clinical failure. High-dose TGC therapy had a higher clinical success rate [65.0% (13/20) versus 18.2% (2/11), P = 0.023] and a lower ICU mortality rate [30.0% (6/20) versus 72.7% (8/11), P = 0.031] than the standard-dose therapy. Conclusions. TGC, especially a high-dose regimen, might be a justifiable option for critically ill patients with nosocomial pneumonia due to CRGNB who have received IIAT when the options for these patients are limited.
Collapse
|
60
|
Gaillard T, Madamet M, Tsombeng FF, Dormoi J, Pradines B. Antibiotics in malaria therapy: which antibiotics except tetracyclines and macrolides may be used against malaria? Malar J 2016; 15:556. [PMID: 27846898 PMCID: PMC5109779 DOI: 10.1186/s12936-016-1613-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 11/10/2016] [Indexed: 01/15/2023] Open
Abstract
Malaria, a parasite vector-borne disease, is one of the most significant health threats in tropical regions, despite the availability of individual chemoprophylaxis. Malaria chemoprophylaxis and chemotherapy remain a major area of research, and new drug molecules are constantly being developed before drug-resistant parasites strains emerge. The use of anti-malarial drugs is challenged by contra-indications, the level of resistance of Plasmodium falciparum in endemic areas, clinical tolerance and financial cost. New therapeutic approaches are currently needed to fight against this disease. Some antibiotics that have shown potential effects on malaria parasite have been recently studied in vitro or in vivo intensively. Two families, tetracyclines and macrolides and their derivatives have been particularly studied in recent years. However, other less well-known have been tested or are being used for malaria treatment. Some of these belong to older families, such as quinolones, co-trimoxazole or fusidic acid, while others are new drug molecules such as tigecycline. These emerging antibiotics could be used to prevent malaria in the future. In this review, the authors overview the use of antibiotics for malaria treatment.
Collapse
Affiliation(s)
- Tiphaine Gaillard
- Fédération des Laboratoires, Hôpital d'Instruction des Armées Saint Anne, Toulon, France.,Unité de Parasitologie et d'Entomologie, Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, Marseille, France.,Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Aix Marseille Université, UM 63, CNRS 7278, IRD 198, Inserm 1095, Marseille, France
| | - Marylin Madamet
- Unité de Parasitologie et d'Entomologie, Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, Marseille, France.,Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Aix Marseille Université, UM 63, CNRS 7278, IRD 198, Inserm 1095, Marseille, France.,Centre National de Référence du Paludisme, Marseille, France
| | - Francis Foguim Tsombeng
- Unité de Parasitologie et d'Entomologie, Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, Marseille, France.,Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Aix Marseille Université, UM 63, CNRS 7278, IRD 198, Inserm 1095, Marseille, France
| | - Jérôme Dormoi
- Unité de Parasitologie et d'Entomologie, Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, Marseille, France.,Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Aix Marseille Université, UM 63, CNRS 7278, IRD 198, Inserm 1095, Marseille, France
| | - Bruno Pradines
- Unité de Parasitologie et d'Entomologie, Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, Marseille, France. .,Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Aix Marseille Université, UM 63, CNRS 7278, IRD 198, Inserm 1095, Marseille, France. .,Centre National de Référence du Paludisme, Marseille, France.
| |
Collapse
|
61
|
Reed GA, Schiller GJ, Kambhampati S, Tallman MS, Douer D, Minden MD, Yee KW, Gupta V, Brandwein J, Jitkova Y, Gronda M, Hurren R, Shamas-Din A, Schuh AC, Schimmer AD. A Phase 1 study of intravenous infusions of tigecycline in patients with acute myeloid leukemia. Cancer Med 2016; 5:3031-3040. [PMID: 27734609 PMCID: PMC5119957 DOI: 10.1002/cam4.845] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 06/07/2016] [Accepted: 07/08/2016] [Indexed: 01/27/2023] Open
Abstract
Acute myeloid leukemia (AML) cells meet the higher energy, metabolic, and signaling demands of the cell by increasing mitochondrial biogenesis and mitochondrial protein translation. Blocking mitochondrial protein synthesis through genetic and chemical approaches kills human AML cells at all stages of development in vitro and in vivo. Tigecycline is an antimicrobial that we found inhibits mitochondrial protein synthesis in AML cells. Therefore, we conducted a phase 1 dose‐escalation study of tigecycline administered intravenously daily 5 of 7 days for 2 weeks to patients with AML. A total of 27 adult patients with relapsed and refractory AML were enrolled in this study with 42 cycles being administered over seven dose levels (50–350 mg/day). Two patients experienced DLTs related to tigecycline at the 350 mg/day level resulting in a maximal tolerated dose of tigecycline of 300 mg as a once daily infusion. Pharmacokinetic experiments showed that tigecycline had a markedly shorter half‐life in these patients than reported for noncancer patients. No significant pharmacodynamic changes or clinical responses were observed. Thus, we have defined the safety of once daily tigecycline in patients with refractory AML. Future studies should focus on schedules of the drug that permit more sustained target inhibition.
Collapse
Affiliation(s)
| | - Gary J Schiller
- David Geffen School of Medicine at UCLA, Los Angeles, California
| | | | - Martin S Tallman
- Leukemia Service, Department of Medicine, Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Dan Douer
- Leukemia Service, Department of Medicine, Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Mark D Minden
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Karen W Yee
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Vikas Gupta
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Joseph Brandwein
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada.,Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Yulia Jitkova
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Marcela Gronda
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Rose Hurren
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Aisha Shamas-Din
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Andre C Schuh
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Aaron D Schimmer
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| |
Collapse
|
62
|
Heidrich CG, Mitova S, Schedlbauer A, Connell SR, Fucini P, Steenbergen JN, Berens C. The Novel Aminomethylcycline Omadacycline Has High Specificity for the Primary Tetracycline-Binding Site on the Bacterial Ribosome. Antibiotics (Basel) 2016; 5:antibiotics5040032. [PMID: 27669321 PMCID: PMC5187513 DOI: 10.3390/antibiotics5040032] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Revised: 09/01/2016] [Accepted: 09/12/2016] [Indexed: 01/02/2023] Open
Abstract
Omadacycline is an aminomethylcycline antibiotic with potent activity against many Gram-positive and Gram-negative pathogens, including strains carrying the major efflux and ribosome protection resistance determinants. This makes it a promising candidate for therapy of severe infectious diseases. Omadacycline inhibits bacterial protein biosynthesis and competes with tetracycline for binding to the ribosome. Its interactions with the 70S ribosome were, therefore, analyzed in great detail and compared with tigecycline and tetracycline. All three antibiotics are inhibited by mutations in the 16S rRNA that mediate resistance to tetracycline in Brachyspira hyodysenteriae, Helicobacter pylori, Mycoplasma hominis, and Propionibacterium acnes. Chemical probing with dimethyl sulfate and Fenton cleavage with iron(II)-complexes of the tetracycline derivatives revealed that each antibiotic interacts in an idiosyncratic manner with the ribosome. X-ray crystallography had previously revealed one primary binding site for tetracycline on the ribosome and up to five secondary sites. All tetracyclines analyzed here interact with the primary site and tetracycline also with two secondary sites. In addition, each derivative displays a unique set of non-specific interactions with the 16S rRNA.
Collapse
Affiliation(s)
- Corina G Heidrich
- Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany.
| | - Sanya Mitova
- Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany.
| | | | - Sean R Connell
- Structural Biology Unit, CIC bioGUNE, 48160 Derio, Bizkaia, Spain.
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain.
| | - Paola Fucini
- Structural Biology Unit, CIC bioGUNE, 48160 Derio, Bizkaia, Spain.
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain.
| | | | - Christian Berens
- Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany.
- Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut, 07743 Jena, Germany.
| |
Collapse
|
63
|
Lee SM, Kwon HY, Im JH, Baek JH, Hwang SS, Kang JS, Chung MH, Lee JS. In Vitro Activity of Tigecycline Against Orientia tsutsugamushi. Yonsei Med J 2016; 57:1034-7. [PMID: 27189302 PMCID: PMC4951447 DOI: 10.3349/ymj.2016.57.4.1034] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 09/10/2015] [Accepted: 09/14/2015] [Indexed: 11/27/2022] Open
Abstract
Scrub typhus is a zoonosis caused by Orientia tsutsugamushi (O. tsutsugamushi) occurring mainly in autumn in Korea. The need of new antibiotics has arisen with a report on strains resistant to antibiotics and chronic infection. This study aims to identify susceptibility of tigecycline in-vitro as a new therapeutic option for O. tsutsugamushi. Antibacterial activity of tigecycline against the O. tsutsugamushi was compared with doxycycline using flow cytometry assay. The inhibitory concentration 50 (IC₅₀) was 3.59×10⁻³ μg/mL in doxycycline-treated group. Whereas in 0.71×10⁻³ μg/mL tigecycline-treated group. These findings indicate that tigecycline may be a therapeutic option for the treatment of scrub typhus.
Collapse
Affiliation(s)
- Sun Myoung Lee
- Translation Research Center, Inha University School of Medicine, Incheon, Korea
| | - Hae Yoon Kwon
- Department of Internal Medicine, Inha University School of Medicine, Incheon, Korea
| | - Jae Hyoung Im
- Department of Internal Medicine, Inha University School of Medicine, Incheon, Korea
| | - Ji Hyeon Baek
- Department of Internal Medicine, Inha University School of Medicine, Incheon, Korea
| | - Seung Sik Hwang
- Department of Social & Preventive Medicine, Inha University School of Medicine, Incheon, Korea
| | - Jae Seung Kang
- Department of Microbiology, Inha University School of Medicine, Incheon, Korea
| | - Moon Hyun Chung
- Department of Internal Medicine, Hanmaeum Hospital, Jeju, Korea
| | - Jin Soo Lee
- Department of Internal Medicine, Inha University School of Medicine, Incheon, Korea.
| |
Collapse
|
64
|
Li R, Han Y, Zhou Y, Du Z, Wu H, Wang J, Chen Y. Tigecycline Susceptibility and Molecular Resistance Mechanisms Among Clinical Klebsiella pneumoniae Strains Isolated During Non-Tigecycline Treatment. Microb Drug Resist 2016; 23:139-146. [PMID: 27219271 DOI: 10.1089/mdr.2015.0258] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Tigecycline is one of the few therapeutic options that are available for treating serious clinical infections. However, tigecycline nonsusceptible Enterobacteriaceae has emerged recently in China. In this study, a total of 28 clinical Klebsiella pneumoniae isolates that were not previously exposed to tigecycline were collected and confirmed for tigecycline minimum inhibitory concentrations (MICs) using standard broth microdilution tests. To elucidate the mechanisms underlying molecular resistance to tigecycline, the expression levels of efflux pumps AcrAB and OqxAB and their regulators RamA, MarA, RarA, and SoxS were determined by quantitative polymerase chain reaction. The expression levels of the genes acrB, ramA, marA, and soxS were statistically different in different MIC groups (p < 0.05). Sequence analysis of the acrR and ramR genes revealed several nonsynonymous mutations in the nine resistance isolates. The values of MIC in these isolated strains with ramR mutations were significantly higher than those without ramR mutation (p = 0.029). Moreover, mutations in the ramR gene led to the overexpression of RamA. These results indicated that the mutation of the ramR gene through the upregulated expression of RamA contributed to tigecycline resistance and that several of the newly identified types of mutations in ramR and acrR were not previously reported in K. pneumoniae clinical isolates.
Collapse
Affiliation(s)
- Ruilian Li
- 1 Department of Biotechnology, Dalian Medical University , Dalian, China
| | - Yujia Han
- 1 Department of Biotechnology, Dalian Medical University , Dalian, China
| | - Yiheng Zhou
- 2 Institute for Chronic and Non-Communicable Disease Prevention and Control , Dalian Center for Disease Prevention and Control, Dalian, China
| | - Zemin Du
- 1 Department of Biotechnology, Dalian Medical University , Dalian, China
| | - Hao Wu
- 1 Department of Biotechnology, Dalian Medical University , Dalian, China
| | - Jing Wang
- 1 Department of Biotechnology, Dalian Medical University , Dalian, China
| | - Yang Chen
- 1 Department of Biotechnology, Dalian Medical University , Dalian, China
| |
Collapse
|
65
|
Lee SH, Teo J, Heng D, Ng WK, Zhao Y, Tan RB. Tailored Antibiotic Combination Powders for Inhaled Rotational Antibiotic Therapy. J Pharm Sci 2016; 105:1501-12. [DOI: 10.1016/j.xphs.2016.02.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 01/28/2016] [Accepted: 02/05/2016] [Indexed: 12/28/2022]
|
66
|
Abstract
Tetracyclines possess many properties considered ideal for antibiotic drugs, including activity against Gram-positive and -negative pathogens, proven clinical safety, acceptable tolerability, and the availability of intravenous (IV) and oral formulations for most members of the class. As with all antibiotic classes, the antimicrobial activities of tetracyclines are subject to both class-specific and intrinsic antibiotic-resistance mechanisms. Since the discovery of the first tetracyclines more than 60 years ago, ongoing optimization of the core scaffold has produced tetracyclines in clinical use and development that are capable of thwarting many of these resistance mechanisms. New chemistry approaches have enabled the creation of synthetic derivatives with improved in vitro potency and in vivo efficacy, ensuring that the full potential of the class can be explored for use against current and emerging multidrug-resistant (MDR) pathogens, including carbapenem-resistant Enterobacteriaceae, MDR Acinetobacter species, and Pseudomonas aeruginosa.
Collapse
|
67
|
Karachitos A, Grobys D, Antoniewicz M, Jedut S, Jordan J, Kmita H. Human VDAC isoforms differ in their capability to interact with minocycline and to contribute to its cytoprotective activity. Mitochondrion 2016; 28:38-48. [PMID: 26994639 DOI: 10.1016/j.mito.2016.03.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 01/21/2016] [Accepted: 03/14/2016] [Indexed: 11/19/2022]
Abstract
It has been previously demonstrated that cytoprotective activity displayed by minocycline in the case of the yeast Saccharomyces cerevisiae cells pretreated with H2O2 requires the presence of functional VDAC (YVDAC1). Thus, we decided to transform YVDAC1-depleted yeast cells (Δpor1 cells) with plasmids expressing human VDAC isoforms (HVDAC1, HVDAC2, HVDAC3) to estimate their involvement in the minocycline cytoprotective effect. We observed that only expression of HVDAC3 in Δpor1 cells provided minocycline-mediated cytoprotection against H2O2 although all human isoforms are functional in Δpor1 cells. The observation appears to be important for on-going discussion concerning VDAC isoform roles in mitochondria and cell functioning.
Collapse
Affiliation(s)
- Andonis Karachitos
- Laboratory of Bioenergetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Daria Grobys
- Laboratory of Bioenergetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Monika Antoniewicz
- Laboratory of Bioenergetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Sylwia Jedut
- Laboratory of Bioenergetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Joaquin Jordan
- Department of Medical Sciences, University of Castilla-La Mancha, School of Medicine, Albacete, Spain
| | - Hanna Kmita
- Laboratory of Bioenergetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland.
| |
Collapse
|
68
|
Dhanalakshmi V, Nimal TR, Sabitha M, Biswas R, Jayakumar R. Skin and muscle permeating antibacterial nanoparticles for treating Staphylococcus aureus infected wounds. J Biomed Mater Res B Appl Biomater 2016; 104:797-807. [PMID: 26898355 DOI: 10.1002/jbm.b.33635] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 01/13/2016] [Accepted: 01/31/2016] [Indexed: 12/13/2022]
Abstract
Majority of the chronic wounds are infected with bacteria like Staphylococcus aureus (S. aureus). The deep tissue infections are difficult to treat using topical antibiotics, due to their poor tissue penetration. In order to treat S. aureus deep tissue infections we have developed an antibiotic delivery system using chitosan nanoparticles (CNPs). To enhance their tissue penetration these CNPs were further coated using lecithin (CLNPs). Antibiotic tigecycline was loaded into chitosan nanoparticles (tCNPs) and then coated with lecithin to generate lecithin coated tigecycline loaded chitosan nanoparticles (tCLNPs). The prepared nanoparticles were characterized using DLS, SEM, TEM and FT-IR. The prepared CNPs, tCNPs, CLNPs and tCLNPs have the size range of 85 ± 10, 90 ± 18, 188 ± 5 and 235 ± 20 nm, respectively. The tCLNPs shows more sustained release pattern of tigecycline. The antibacterial activity of the developed nanoparticles was confirmed against laboratory and clinical strains of S. aureus using in vitro and ex vivo experiments. The ex vivo skin and muscle permeation study ensures the enhanced delivery of tigecycline to the deeper tissue. The prepared nanoparticles were hemo-compatible and cyto-compatible. Our study suggests that the prepared tCLNPs can be effectively used for the treatment of S. aureus infected wounds.
Collapse
Affiliation(s)
- V Dhanalakshmi
- Amrita Centre for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham University, Kochi, 682041, India
| | - T R Nimal
- Amrita Centre for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham University, Kochi, 682041, India
| | - M Sabitha
- Amrita School of Pharmacy, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham University, Kochi, 682041, India
| | - Raja Biswas
- Amrita Centre for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham University, Kochi, 682041, India
| | - R Jayakumar
- Amrita Centre for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham University, Kochi, 682041, India
| |
Collapse
|
69
|
Fiedler S, Bender JK, Klare I, Halbedel S, Grohmann E, Szewzyk U, Werner G. Tigecycline resistance in clinical isolates of Enterococcus faecium is mediated by an upregulation of plasmid-encoded tetracycline determinants tet(L) and tet(M). J Antimicrob Chemother 2015; 71:871-81. [PMID: 26682961 DOI: 10.1093/jac/dkv420] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 11/05/2015] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES Tigecycline represents one of the last-line therapeutics to combat multidrug-resistant bacterial pathogens, including VRE and MRSA. The German National Reference Centre for Staphylococci and Enterococci has received 73 tigecycline-resistant Enterococcus faecium and Enterococcus faecalis isolates in recent years. The precise mechanism of how enterococci become resistant to tigecycline remains undetermined. This study documents an analysis of the role of efflux pumps in tigecycline resistance in clinical isolates of Enterococcus spp. METHODS Various tigecycline MICs were found for the different isolates analysed. Tigecycline-resistant strains were analysed with respect to genome and transcriptome differences by means of WGS and RT-qPCR. Genes of interest were cloned and expressed in Listeria monocytogenes for verification of their functionality. RESULTS Detailed comparative whole-genome analyses of three isogenic strains, showing different levels of tigecycline resistance, revealed the major facilitator superfamily (MFS) efflux pump TetL and the ribosomal protection protein TetM as possible drug resistance proteins. Subsequent RT-qPCR confirmed up-regulation of the respective genes. A correlation of gene copy number and level of MIC was inferred from further qPCR analyses. Expression of both tet(L) and tet(M) in L. monocytogenes unequivocally demonstrated the potential to increase tigecycline MICs upon acquisition of either locus. CONCLUSIONS Our results indicate that increased expression of two tetracycline resistance determinants, a tet(L)-encoded MFS pump and a tet(M)-encoded ribosomal protection protein, is capable of conferring tigecycline resistance in enterococcal clinical isolates.
Collapse
Affiliation(s)
- S Fiedler
- Division of Nosocomial Pathogens and Antibiotic Resistances, National Reference Centre for Staphylococci and Enterococci, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, Wernigerode, Germany
| | - J K Bender
- Division of Nosocomial Pathogens and Antibiotic Resistances, National Reference Centre for Staphylococci and Enterococci, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, Wernigerode, Germany
| | - I Klare
- Division of Nosocomial Pathogens and Antibiotic Resistances, National Reference Centre for Staphylococci and Enterococci, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, Wernigerode, Germany
| | - S Halbedel
- Division of Enteropathogenic Bacteria and Legionella, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, Wernigerode, Germany
| | - E Grohmann
- Department of Life Sciences and Technology, Beuth University of Applied Sciences, Berlin, Germany Division of Infectious Diseases, University Medical Centre Freiburg, Freiburg, Germany
| | - U Szewzyk
- Environmental Microbiology, Technical University Berlin, Berlin, Germany
| | - G Werner
- Division of Nosocomial Pathogens and Antibiotic Resistances, National Reference Centre for Staphylococci and Enterococci, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, Wernigerode, Germany
| |
Collapse
|
70
|
Hart T, Chandrashekhar M, Aregger M, Steinhart Z, Brown KR, MacLeod G, Mis M, Zimmermann M, Fradet-Turcotte A, Sun S, Mero P, Dirks P, Sidhu S, Roth FP, Rissland OS, Durocher D, Angers S, Moffat J. High-Resolution CRISPR Screens Reveal Fitness Genes and Genotype-Specific Cancer Liabilities. Cell 2015; 163:1515-26. [PMID: 26627737 DOI: 10.1016/j.cell.2015.11.015] [Citation(s) in RCA: 1016] [Impact Index Per Article: 112.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 09/01/2015] [Accepted: 10/30/2015] [Indexed: 01/17/2023]
Abstract
The ability to perturb genes in human cells is crucial for elucidating gene function and holds great potential for finding therapeutic targets for diseases such as cancer. To extend the catalog of human core and context-dependent fitness genes, we have developed a high-complexity second-generation genome-scale CRISPR-Cas9 gRNA library and applied it to fitness screens in five human cell lines. Using an improved Bayesian analytical approach, we consistently discover 5-fold more fitness genes than were previously observed. We present a list of 1,580 human core fitness genes and describe their general properties. Moreover, we demonstrate that context-dependent fitness genes accurately recapitulate pathway-specific genetic vulnerabilities induced by known oncogenes and reveal cell-type-specific dependencies for specific receptor tyrosine kinases, even in oncogenic KRAS backgrounds. Thus, rigorous identification of human cell line fitness genes using a high-complexity CRISPR-Cas9 library affords a high-resolution view of the genetic vulnerabilities of a cell.
Collapse
Affiliation(s)
- Traver Hart
- Donnelly Centre, 160 College Street, Toronto, ON M5S3E1, Canada
| | - Megha Chandrashekhar
- Donnelly Centre, 160 College Street, Toronto, ON M5S3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S1A1, Canada
| | - Michael Aregger
- Donnelly Centre, 160 College Street, Toronto, ON M5S3E1, Canada
| | - Zachary Steinhart
- Department of Pharmaceutical Sciences and Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S1A1, Canada
| | - Kevin R Brown
- Donnelly Centre, 160 College Street, Toronto, ON M5S3E1, Canada
| | - Graham MacLeod
- Department of Pharmaceutical Sciences and Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S1A1, Canada
| | - Monika Mis
- Department of Pharmaceutical Sciences and Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S1A1, Canada
| | - Michal Zimmermann
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G1X5, Canada
| | - Amelie Fradet-Turcotte
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G1X5, Canada
| | - Song Sun
- Donnelly Centre, 160 College Street, Toronto, ON M5S3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S1A1, Canada; Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala SE-75123, Sweden; Department of Computer Science, University of Toronto, Toronto, ON M5G1X8, Canada
| | - Patricia Mero
- Donnelly Centre, 160 College Street, Toronto, ON M5S3E1, Canada
| | - Peter Dirks
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S1A1, Canada; Program in Developmental and Stem Cell Biology, Division of Neurosurgery, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G1X8, Canada
| | - Sachdev Sidhu
- Donnelly Centre, 160 College Street, Toronto, ON M5S3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S1A1, Canada
| | - Frederick P Roth
- Donnelly Centre, 160 College Street, Toronto, ON M5S3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S1A1, Canada; The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G1X5, Canada; Department of Computer Science, University of Toronto, Toronto, ON M5G1X8, Canada; Canadian Institute for Advanced Research, Toronto, ON M5G1Z8, Canada; Center for Cancer Systems Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Olivia S Rissland
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S1A1, Canada; Molecular Structure and Function Program, The Hospital for Sick Children Research Institute, 686 Bay Street, Toronto, ON M5G0A4, Canada
| | - Daniel Durocher
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S1A1, Canada; The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G1X5, Canada
| | - Stephane Angers
- Department of Pharmaceutical Sciences and Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S1A1, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S1A1, Canada
| | - Jason Moffat
- Donnelly Centre, 160 College Street, Toronto, ON M5S3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S1A1, Canada; Canadian Institute for Advanced Research, Toronto, ON M5G1Z8, Canada.
| |
Collapse
|
71
|
Potential of Tetracycline Resistance Proteins To Evolve Tigecycline Resistance. Antimicrob Agents Chemother 2015; 60:789-96. [PMID: 26596936 PMCID: PMC4750697 DOI: 10.1128/aac.02465-15] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 11/12/2015] [Indexed: 11/20/2022] Open
Abstract
Tigecycline is a glycylcycline antibiotic active against multidrug-resistant bacterial pathogens. The objectives of our study were to examine the potential of the Tet(A), Tet(K), Tet(M), and Tet(X) tetracycline resistance proteins to acquire mutations causing tigecycline resistance and to determine how this affects resistance to earlier classes of tetracyclines. Mutations in all four tet genes caused a significant increase in the tigecycline MIC in Escherichia coli, and strains expressing mutant Tet(A) and Tet(X) variants reached clinically relevant MICs (2 mg/liter and 3 mg/liter, respectively). Mutations predominantly accumulated in transmembrane domains of the efflux pumps, most likely increasing the accommodation of tigecycline as a substrate. All selected Tet(M) mutants contained at least one mutation in the functionally most important loop III of domain IV. Deletion of leucine 505 of this loop led to the highest increase of the tigecycline MIC (0.5 mg/liter) among Tet(M) mutants. It also caused collateral sensitivity to earlier classes of tetracyclines. A majority of the Tet(X) mutants showed increased activity against all three classes of tetracylines. All tested Tet proteins have the potential to acquire mutations leading to increased MICs of tigecycline. As tet genes are widely found in pathogenic bacteria and spread easily by horizontal gene transfer, resistance development by alteration of existing Tet proteins might compromise the future medical use of tigecycline. We predict that Tet(X) might become the most problematic future Tet determinant, since its weak intrinsic tigecycline activity can be mutationally improved to reach clinically relevant levels without collateral loss in activity to other tetracyclines.
Collapse
|
72
|
Induced tigecycline resistance inStreptococcus pneumoniaemutants reveals mutations in ribosomal proteins and rRNA. J Antimicrob Chemother 2015; 70:2973-80. [DOI: 10.1093/jac/dkv211] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 06/21/2015] [Indexed: 11/12/2022] Open
|
73
|
The ribosomal S10 protein is a general target for decreased tigecycline susceptibility. Antimicrob Agents Chemother 2015; 59:5561-6. [PMID: 26124155 DOI: 10.1128/aac.00547-15] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 06/21/2015] [Indexed: 12/30/2022] Open
Abstract
Tigecycline is a translational inhibitor with efficacy against a wide range of pathogens. Using experimental evolution, we adapted Acinetobacter baumannii, Enterococcus faecium, Escherichia coli, and Staphylococcus aureus to growth in elevated tigecycline concentrations. At the end of adaptation, 35 out of 47 replicate populations had clones with a mutation in rpsJ, the gene that encodes the ribosomal S10 protein. To validate the role of mutations in rpsJ in conferring tigecycline resistance, we showed that mutation of rpsJ alone in Enterococcus faecalis was sufficient to increase the tigecycline MIC to the clinical breakpoint of 0.5 μg/ml. Importantly, we also report the first identification of rpsJ mutations associated with decreased tigecycline susceptibility in A. baumannii, E. coli, and S. aureus. The identified S10 mutations across both Gram-positive and -negative species cluster in the vertex of an extended loop that is located near the tigecycline-binding pocket within the 16S rRNA. These data indicate that S10 is a general target of tigecycline adaptation and a relevant marker for detecting reduced susceptibility in both Gram-positive and -negative pathogens.
Collapse
|
74
|
Beabout K, Hammerstrom TG, Wang TT, Bhatty M, Christie PJ, Saxer G, Shamoo Y. Rampant Parasexuality Evolves in a Hospital Pathogen during Antibiotic Selection. Mol Biol Evol 2015; 32:2585-97. [PMID: 26060280 DOI: 10.1093/molbev/msv133] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Horizontal gene transfer threatens the therapeutic success of antibiotics by facilitating the rapid dissemination of resistance alleles among bacterial species. The conjugative mobile element Tn916 provides an excellent context for examining the role of adaptive parasexuality as it carries the tetracycline-resistance allele tetM and has been identified in a wide range of pathogens. We have used a combination of experimental evolution and allelic frequency measurements to gain insights into the adaptive trajectories leading to tigecycline resistance in a hospital strain of Enterococcus faecalis and predict what mechanisms of resistance are most likely to appear in the clinical setting. Here, we show that antibiotic selection led to the near fixation of adaptive alleles that simultaneously altered TetM expression and produced remarkably increased levels of Tn916 horizontal gene transfer. In the absence of drug, approximately 1 in 120,000 of the nonadapted E. faecalis S613 cells had an excised copy of Tn916, whereas nearly 1 in 50 cells had an excised copy of Tn916 upon selection for resistance resulting in a more than 1,000-fold increase in conjugation rates. We also show that tigecycline, a translation inhibitor, selected for a mutation in the ribosomal S10 protein. Our results show the first example of mutations that concurrently confer resistance to an antibiotic and lead to constitutive conjugal-transfer of the resistance allele. Selection created a highly parasexual phenotype and high frequency of Tn916 jumping demonstrating how the use of antibiotics can lead directly to the proliferation of resistance in, and potentially among, pathogens.
Collapse
Affiliation(s)
| | | | - Tim T Wang
- Department of BioSciences, Rice University
| | - Minny Bhatty
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston
| | - Peter J Christie
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston
| | | | | |
Collapse
|
75
|
Wang C, Xiang R, Zhang X, Chen Y. Doxycycline inhibits leukemic cell migration via inhibition of matrix metalloproteinases and phosphorylation of focal adhesion kinase. Mol Med Rep 2015; 12:3374-3380. [PMID: 26004127 PMCID: PMC4526096 DOI: 10.3892/mmr.2015.3833] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 03/16/2015] [Indexed: 01/24/2023] Open
Abstract
Doxycycline, a tetracycline-based antibiotic, has been reported to attenuate melanoma cell migration through inhibiting the focal adhesion kinase (FAK) signaling pathway. However, it remains to be elucidated whether doxycycline exerts this effect on leukemia cell migration. The present study aimed to examine the role of doxycycline in leukemia cell migration. The invasion capacities of the human leukemia cell lines KG1a (acute myelogenous leukemia) and K562 (chronic myelogenous leukemia) were evaluated using Matrigel® matrix‑coated Transwell® chamber assays; leukemic cell lines treated with doxycycline (1 µg/ml) or anti‑β1‑integrin antibodies were added to the upper chamber, while untreated cells were included as controls. Reverse transcription quantitative polymerase chain reaction was performed in order to further understand the influence of doxycycline treatment on the expression of FAK and gelatinases in the KG1a and K562 leukemic cell lines. In addition, FAK protein expression and phosphorylation were determined using western blot analysis in order to investigate the mechanism by which doxycycline inhibited leukemic cell migration. The results revealed that doxycycline treatment significantly attenuated the migration of KG1a and K562 cells, which was demonstrated to be associated with inhibition of the expression and phosphorylation of FAK. In addition, doxycycline treatment inhibited matrix metalloproteinase (MMP)‑2 and MMP‑9 expression. Furthermore, incubation with blocking anti‑β1‑integrin antibodies had an analogous inhibitory effect on leukemic cell migration to that of doxycycline. In conclusion, the results of the present study suggested that doxycycline attenuated leukemic cell migration through inhibiting the FAK signaling pathway. Therefore, doxycycline may have potential for use as a novel strategy for the treatment of leukemia.
Collapse
Affiliation(s)
- Chunhuai Wang
- Department of Hematology, The First Affiliated Hospital of Sun Yat‑Sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Ru Xiang
- Department of Internal Medicine, School of Nursing, Anhui Medical University, Hefei, Anhui 230601, P.R. China
| | - Xiangzhong Zhang
- Department of Hematology, The First Affiliated Hospital of Sun Yat‑Sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Yunxian Chen
- Department of Hematology, The First Affiliated Hospital of Sun Yat‑Sen University, Guangzhou, Guangdong 510080, P.R. China
| |
Collapse
|
76
|
Cryo-EM structure of the tetracycline resistance protein TetM in complex with a translating ribosome at 3.9-Å resolution. Proc Natl Acad Sci U S A 2015; 112:5401-6. [PMID: 25870267 DOI: 10.1073/pnas.1501775112] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ribosome protection proteins (RPPs) confer resistance to tetracycline by binding to the ribosome and chasing the drug from its binding site. Current models for RPP action are derived from 7.2- to 16-Å resolution structures of RPPs bound to vacant or nontranslating ribosomes. Here we present a cryo-electron microscopy reconstruction of the RPP TetM in complex with a translating ribosome at 3.9-Å resolution. The structure reveals the contacts of TetM with the ribosome, including interaction between the conserved and functionally critical C-terminal extension of TetM with a unique splayed conformation of nucleotides A1492 and A1493 at the decoding center of the small subunit. The resolution enables us to unambiguously model the side chains of the amino acid residues comprising loop III in domain IV of TetM, revealing that the tyrosine residues Y506 and Y507 are not responsible for drug-release as suggested previously but rather for intrafactor contacts that appear to stabilize the conformation of loop III. Instead, Pro509 at the tip of loop III is located directly within the tetracycline binding site where it interacts with nucleotide C1054 of the 16S rRNA, such that RPP action uses Pro509, rather than Y506/Y507, to directly dislodge and release tetracycline from the ribosome.
Collapse
|
77
|
Structural characterization of an alternative mode of tigecycline binding to the bacterial ribosome. Antimicrob Agents Chemother 2015; 59:2849-54. [PMID: 25753625 DOI: 10.1128/aac.04895-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 02/27/2015] [Indexed: 11/20/2022] Open
Abstract
Although both tetracycline and tigecycline inhibit protein synthesis by sterically hindering the binding of tRNA to the ribosomal A site, tigecycline shows increased efficacy in both in vitro and in vivo activity assays and escapes the most common resistance mechanisms associated with the tetracycline class of antibiotics. These differences in activities are attributed to the tert-butyl-glycylamido side chain found in tigecycline. Our structural analysis by X-ray crystallography shows that tigecycline binds the bacterial 30S ribosomal subunit with its tail in an extended conformation and makes extensive interactions with the 16S rRNA nucleotide C1054. These interactions restrict the mobility of C1054 and contribute to the antimicrobial activity of tigecycline, including its resistance to the ribosomal protection proteins.
Collapse
|
78
|
Jha BK, Seo I, Kong HH, Suh SI, Suh MH, Baek WK. Tigecycline inhibits proliferation of Acanthamoeba castellanii. Parasitol Res 2015; 114:1189-95. [DOI: 10.1007/s00436-014-4302-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 12/23/2014] [Indexed: 10/24/2022]
|
79
|
In vitro activities of rifampin, colistin, sulbactam and tigecycline tested alone and in combination against extensively drug-resistant Acinetobacter baumannii. J Antibiot (Tokyo) 2014; 67:677-80. [DOI: 10.1038/ja.2014.99] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 06/08/2014] [Accepted: 06/22/2014] [Indexed: 11/08/2022]
|
80
|
Jitkova Y, Gronda M, Hurren R, Wang X, Goard CA, Jhas B, Schimmer AD. A novel formulation of tigecycline has enhanced stability and sustained antibacterial and antileukemic activity. PLoS One 2014; 9:e95281. [PMID: 24871339 PMCID: PMC4037176 DOI: 10.1371/journal.pone.0095281] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 03/25/2014] [Indexed: 01/23/2023] Open
Abstract
Tigecycline is a broad-spectrum, first-in-class glycylcycline antibiotic currently used to treat complicated skin and intra-abdominal infections, as well as community-acquired pneumonia. In addition, we have demonstrated that tigecycline also has in vitro and in vivo activity against acute myeloid leukemia (AML) due to its ability to inhibit mitochondrial translation. Tigecycline is relatively unstable after reconstitution, and this instability may limit the use of the drug in ambulatory infusions for the treatment of infection and may prevent the development of optimal dosing schedules for the treatment of AML. This study sought to identify a formulation that improved the stability of the drug after reconstitution and maintained its antimicrobial and antileukemic activity. A panel of chemical additives was tested to identify excipients that enhanced the stability of tigecycline in solution at room temperature for up to one week. We identified a novel formulation containing the oxygen-reducing agents ascorbic acid (3 mg/mL) and pyruvate (60 mg/mL), in saline solution, pH 7.0, in which tigecycline (1 mg/mL) remained intact when protected from light for at least 7 days. This formulation also preserved the drug's antibacterial and antileukemic activity in vitro. Moreover, the novel formulation retained tigecycline's antileukemic activity in vivo. Thus, we identified and characterized a novel formulation for tigecycline that preserves its stability and efficacy after reconstitution.
Collapse
Affiliation(s)
- Yulia Jitkova
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Marcela Gronda
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Rose Hurren
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Xiaoming Wang
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Carolyn A. Goard
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Bozhena Jhas
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Aaron D. Schimmer
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
- * E-mail:
| |
Collapse
|
81
|
Gostelow M, Gonzalez D, Smith PB, Cohen-Wolkowiez M. Pharmacokinetics and safety of recently approved drugs used to treat methicillin-resistant Staphylococcus aureus infections in infants, children and adults. Expert Rev Clin Pharmacol 2014; 7:327-40. [PMID: 24716805 PMCID: PMC4032771 DOI: 10.1586/17512433.2014.909281] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) remains a significant cause of morbidity in hospitalized infants. Over the past 15 years, several drugs have been approved for the treatment of S. aureus infections in adults (linezolid, quinupristin/dalfopristin, daptomycin, telavancin, tigecycline and ceftaroline). The use of the majority of these drugs has extended into the treatment of MRSA infections in infants, frequently with minimal safety or dosing information. Only linezolid is approved for use in infants, and pharmacokinetic data in infants are limited to linezolid and daptomycin. Pediatric trials are underway for ceftaroline, telavancin, and daptomycin; however, none of these studies includes infants. Here, we review current pharmacokinetic, safety and efficacy data of these drugs with a specific focus in infants.
Collapse
Affiliation(s)
- Martyn Gostelow
- Duke Clinical Research Institute, Duke University Medical Center, Durham, NC, USA
| | - Daniel Gonzalez
- Duke Clinical Research Institute, Duke University Medical Center, Durham, NC, USA
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - P. Brian Smith
- Duke Clinical Research Institute, Duke University Medical Center, Durham, NC, USA
- Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
| | - Michael Cohen-Wolkowiez
- Duke Clinical Research Institute, Duke University Medical Center, Durham, NC, USA
- Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
| |
Collapse
|
82
|
Abstract
The ribosome is one of the main antibiotic targets in the bacterial cell. Crystal structures of naturally produced antibiotics and their semi-synthetic derivatives bound to ribosomal particles have provided unparalleled insight into their mechanisms of action, and they are also facilitating the design of more effective antibiotics for targeting multidrug-resistant bacteria. In this Review, I discuss the recent structural insights into the mechanism of action of ribosome-targeting antibiotics and the molecular mechanisms of bacterial resistance, in addition to the approaches that are being pursued for the production of improved drugs that inhibit bacterial protein synthesis.
Collapse
|
83
|
Ribatski-Silva D, Bassi CL, Martin TOG, Alves-Junior E, Gomes LT, Fontes CJF. In vitro antimalarial activity of tigecycline against Plasmodium falciparum culture-adapted reference strains and clinical isolates from the Brazilian Amazon. Rev Soc Bras Med Trop 2014; 47:110-2. [PMID: 24553805 DOI: 10.1590/0037-8682-0013-2012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 02/09/2013] [Indexed: 11/21/2022] Open
Abstract
INTRODUCTION We evaluated the in vitro antimalarial activity of tigecycline as an alternative drug for the treatment of severe malaria. METHODS A chloroquine-sensitive Plasmodium falciparum reference strain, a chloroquine-resistant reference strain, and three clinical isolates were tested for in vitro susceptibility to tigecycline. A histidine-rich protein in vitro assay was used to evaluate antimalarial activity. RESULTS The geometric-mean 50% effective concentration (EC50%) of tigecycline was 535.5 nM (confidence interval (CI): 344.3-726.8). No significant correlation was found between the EC50% of tigecycline and that of any other tested antimalarial drug. CONCLUSIONS Tigecycline may represent an alternative drug for the treatment of patients with severe malaria.
Collapse
Affiliation(s)
- Daniele Ribatski-Silva
- Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal de Mato Grosso, CuiabáMT, Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal de Mato Grosso, Cuiabá, MT
| | - Carmen Lucia Bassi
- Laboratório de Investigação, Faculdade de Medicina, Universidade Federal de Mato Grosso, CuiabáMT, Laboratório de Investigação, Faculdade de Medicina, Universidade Federal de Mato Grosso, Cuiabá, MT
| | - Thamires Oliveira Gasquez Martin
- Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal de Mato Grosso, CuiabáMT, Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal de Mato Grosso, Cuiabá, MT
| | - Eduardo Alves-Junior
- Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal de Mato Grosso, CuiabáMT, Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal de Mato Grosso, Cuiabá, MT
| | - Luciano Teixeira Gomes
- Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal de Mato Grosso, CuiabáMT, Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal de Mato Grosso, Cuiabá, MT
| | - Cor Jésus Fernandes Fontes
- Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal de Mato Grosso, CuiabáMT, Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal de Mato Grosso, Cuiabá, MT
| |
Collapse
|
84
|
Genomics of KPC-producing Klebsiella pneumoniae sequence type 512 clone highlights the role of RamR and ribosomal S10 protein mutations in conferring tigecycline resistance. Antimicrob Agents Chemother 2013; 58:1707-12. [PMID: 24379204 DOI: 10.1128/aac.01803-13] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Full genome sequences were determined for five Klebsiella pneumoniae strains belonging to the sequence type 512 (ST512) clone, producing KPC-3. Three strains were resistant to tigecycline, one showed an intermediate phenotype, and one was susceptible. Comparative analysis performed using the genome of the susceptible strain as a reference sequence identified genetic differences possibly associated with resistance to tigecycline. Results demonstrated that mutations in the ramR gene occurred in two of the three sequenced strains. Mutations in RamR were previously demonstrated to cause overexpression of the AcrAB-TolC efflux system and were implicated in tigecycline resistance in K. pneumoniae. The third strain showed a mutation located at the vertex of a very well conserved loop in the S10 ribosomal protein, which is located in close proximity to the tigecycline target site in the 30S ribosomal subunit. This mutation was previously shown to be associated with tetracycline resistance in Neisseria gonorrhoeae. A PCR-based approach was devised to amplify the potential resistance mechanisms identified by genomics and applied to two additional ST512 strains showing resistance to tigecycline, allowing us to identify mutations in the ramR gene.
Collapse
|
85
|
Deris JB, Kim M, Zhang Z, Okano H, Hermsen R, Groisman A, Hwa T. The innate growth bistability and fitness landscapes of antibiotic-resistant bacteria. Science 2013; 342:1237435. [PMID: 24288338 DOI: 10.1126/science.1237435] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
To predict the emergence of antibiotic resistance, quantitative relations must be established between the fitness of drug-resistant organisms and the molecular mechanisms conferring resistance. These relations are often unknown and may depend on the state of bacterial growth. To bridge this gap, we have investigated Escherichia coli strains expressing resistance to translation-inhibiting antibiotics. We show that resistance expression and drug inhibition are linked in a positive feedback loop arising from an innate, global effect of drug-inhibited growth on gene expression. A quantitative model of bacterial growth based on this innate feedback accurately predicts the rich phenomena observed: a plateau-shaped fitness landscape, with an abrupt drop in the growth rates of cultures at a threshold drug concentration, and the coexistence of growing and nongrowing populations, that is, growth bistability, below the threshold.
Collapse
Affiliation(s)
- J Barrett Deris
- Department of Physics, University of California at San Diego, La Jolla, CA 92093-0374, USA
| | | | | | | | | | | | | |
Collapse
|
86
|
Clark RB, He M, Deng Y, Sun C, Chen CL, Hunt DK, O’Brien WJ, Fyfe C, Grossman TH, Sutcliffe JA, Achorn C, Hogan PC, Katz CE, Niu J, Zhang WY, Zhu Z, Ronn M, Xiao XY. Synthesis and Biological Evaluation of 8-Aminomethyltetracycline Derivatives as Novel Antibacterial Agents. J Med Chem 2013; 56:8112-38. [DOI: 10.1021/jm401211t] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Roger B. Clark
- Discovery Chemistry, ‡Microbiology, and §Process Chemistry R&D, Tetraphase Pharmaceuticals, Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, United States
| | - Minsheng He
- Discovery Chemistry, ‡Microbiology, and §Process Chemistry R&D, Tetraphase Pharmaceuticals, Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, United States
| | - Yonghong Deng
- Discovery Chemistry, ‡Microbiology, and §Process Chemistry R&D, Tetraphase Pharmaceuticals, Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, United States
| | - Cuixiang Sun
- Discovery Chemistry, ‡Microbiology, and §Process Chemistry R&D, Tetraphase Pharmaceuticals, Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, United States
| | - Chi-Li Chen
- Discovery Chemistry, ‡Microbiology, and §Process Chemistry R&D, Tetraphase Pharmaceuticals, Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, United States
| | - Diana K. Hunt
- Discovery Chemistry, ‡Microbiology, and §Process Chemistry R&D, Tetraphase Pharmaceuticals, Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, United States
| | - William J. O’Brien
- Discovery Chemistry, ‡Microbiology, and §Process Chemistry R&D, Tetraphase Pharmaceuticals, Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, United States
| | - Corey Fyfe
- Discovery Chemistry, ‡Microbiology, and §Process Chemistry R&D, Tetraphase Pharmaceuticals, Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, United States
| | - Trudy H. Grossman
- Discovery Chemistry, ‡Microbiology, and §Process Chemistry R&D, Tetraphase Pharmaceuticals, Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, United States
| | - Joyce A. Sutcliffe
- Discovery Chemistry, ‡Microbiology, and §Process Chemistry R&D, Tetraphase Pharmaceuticals, Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, United States
| | - Catherine Achorn
- Discovery Chemistry, ‡Microbiology, and §Process Chemistry R&D, Tetraphase Pharmaceuticals, Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, United States
| | - Philip C. Hogan
- Discovery Chemistry, ‡Microbiology, and §Process Chemistry R&D, Tetraphase Pharmaceuticals, Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, United States
| | - Christopher E. Katz
- Discovery Chemistry, ‡Microbiology, and §Process Chemistry R&D, Tetraphase Pharmaceuticals, Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, United States
| | - John Niu
- Discovery Chemistry, ‡Microbiology, and §Process Chemistry R&D, Tetraphase Pharmaceuticals, Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, United States
| | - Wu-Yan Zhang
- Discovery Chemistry, ‡Microbiology, and §Process Chemistry R&D, Tetraphase Pharmaceuticals, Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, United States
| | - Zhijian Zhu
- Discovery Chemistry, ‡Microbiology, and §Process Chemistry R&D, Tetraphase Pharmaceuticals, Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, United States
| | - Magnus Ronn
- Discovery Chemistry, ‡Microbiology, and §Process Chemistry R&D, Tetraphase Pharmaceuticals, Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, United States
| | - Xiao-Yi Xiao
- Discovery Chemistry, ‡Microbiology, and §Process Chemistry R&D, Tetraphase Pharmaceuticals, Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, United States
| |
Collapse
|
87
|
Zhang J, Ponomareva LV, Marchillo K, Zhou M, Andes DR, Thorson JS. Synthesis and antibacterial activity of doxycycline neoglycosides. JOURNAL OF NATURAL PRODUCTS 2013; 76:1627-36. [PMID: 23987662 PMCID: PMC3814126 DOI: 10.1021/np4003096] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A set of 37 doxycycline neoglycosides were prepared, mediated via a C-9 alkoxyamino-glycyl-based spacer reminiscent of that of tigecycline. Subsequent in vitro antibacterial assays against representative drug-resistant Gram negative and Gram positive strains revealed a sugar-dependent activity profile and one doxycycline neoglycoside, the 2'-amino-α-D-glucoside conjugate, to rival that of the parent pharmacophore. In contrast, the representative tetracycline-susceptible strain E. coli 25922 was found to be relatively responsive to a range of doxycycline neoglycosides. This study also extends the use of aminosugars in the context of neoglycosylation via a simple two-step strategy anticipated to be broadly applicable for neoglycorandomization.
Collapse
Affiliation(s)
- Jianjun Zhang
- Center for Pharmaceutical Research and Innovation, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536-0596, United States
| | - Larissa V. Ponomareva
- Center for Pharmaceutical Research and Innovation, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536-0596, United States
| | - Karen Marchillo
- Department of Medicine and Medical Microbiology and Immunology, University of Wisconsin-Madison, 1685 Highland Avenue, Madison, Wisconsin, 53705-2281, United States
| | - Maoquan Zhou
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, 777 Highland Avenue, Madison, Wisconsin 53705-2222, United States
| | - David R. Andes
- Department of Medicine and Medical Microbiology and Immunology, University of Wisconsin-Madison, 1685 Highland Avenue, Madison, Wisconsin, 53705-2281, United States
| | - Jon S. Thorson
- Center for Pharmaceutical Research and Innovation, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536-0596, United States
| |
Collapse
|
88
|
Mechanism of action of the novel aminomethylcycline antibiotic omadacycline. Antimicrob Agents Chemother 2013; 58:1279-83. [PMID: 24041885 DOI: 10.1128/aac.01066-13] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Omadacycline is a novel first-in-class aminomethylcycline with potent activity against important skin and pneumonia pathogens, including community-acquired methicillin-resistant Staphylococcus aureus (MRSA), β-hemolytic streptococci, penicillin-resistant Streptococcus pneumoniae, Haemophilus influenzae, and Legionella. In this work, the mechanism of action for omadacycline was further elucidated using a variety of models. Functional assays demonstrated that omadacycline is active against strains expressing the two main forms of tetracycline resistance (efflux and ribosomal protection). Macromolecular synthesis experiments confirmed that the primary effect of omadacycline is on bacterial protein synthesis, inhibiting protein synthesis with a potency greater than that of tetracycline. Biophysical studies with isolated ribosomes confirmed that the binding site for omadacycline is similar to that for tetracycline. In addition, unlike tetracycline, omadacycline is active in vitro in the presence of the ribosomal protection protein Tet(O).
Collapse
|
89
|
Volkers G, Damas JM, Palm GJ, Panjikar S, Soares CM, Hinrichs W. Putative dioxygen-binding sites and recognition of tigecycline and minocycline in the tetracycline-degrading monooxygenase TetX. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:1758-67. [PMID: 23999299 DOI: 10.1107/s0907444913013802] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 05/19/2013] [Indexed: 12/28/2022]
Abstract
Expression of the aromatic hydroxylase TetX under aerobic conditions confers bacterial resistance against tetracycline antibiotics. Hydroxylation inactivates and degrades tetracyclines, preventing inhibition of the prokaryotic ribosome. X-ray crystal structure analyses of TetX in complex with the second-generation and third-generation tetracyclines minocycline and tigecycline at 2.18 and 2.30 Å resolution, respectively, explain why both clinically potent antibiotics are suitable substrates. Both tetracyclines bind in a large tunnel-shaped active site in close contact to the cofactor FAD, pre-oriented for regioselective hydroxylation to 11a-hydroxytetracyclines. The characteristic bulky 9-tert-butylglycylamido substituent of tigecycline is solvent-exposed and does not interfere with TetX binding. In the TetX-minocycline complex a second binding site for a minocycline dimer is observed close to the active-site entrance. The pocket is formed by the crystal packing arrangement on the surface of two neighbouring TetX monomers. Crystal structure analysis at 2.73 Å resolution of xenon-pressurized TetX identified two adjacent Xe-binding sites. These putative dioxygen-binding cavities are located in the substrate-binding domain next to the active site. Molecular-dynamics simulations were performed in order to characterize dioxygen-diffusion pathways to FADH2 at the active site.
Collapse
Affiliation(s)
- Gesa Volkers
- Department of Molecular Structural Biology, Institute for Biochemistry, University of Greifswald, Felix-Hausdorff-Strasse 4, Greifswald, Germany
| | | | | | | | | | | |
Collapse
|
90
|
|
91
|
Linkevicius M, Sandegren L, Andersson DI. Mechanisms and fitness costs of tigecycline resistance in Escherichia coli. J Antimicrob Chemother 2013; 68:2809-19. [DOI: 10.1093/jac/dkt263] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
|
92
|
Otto MP, Martin E, Badiou C, Lebrun S, Bes M, Vandenesch F, Etienne J, Lina G, Dumitrescu O. Effects of subinhibitory concentrations of antibiotics on virulence factor expression by community-acquired methicillin-resistant Staphylococcus aureus. J Antimicrob Chemother 2013; 68:1524-32. [PMID: 23508621 DOI: 10.1093/jac/dkt073] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES To examine the effect of subinhibitory concentrations (sub-MICs) of antistaphylococcal drugs on Panton-Valentine leucocidin (PVL), α-haemolysin (Hla) and protein A (SpA) expression by community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). METHODS Five clinical isolates representing the main worldwide CA-MRSA clones were grown with sub-MICs (1/8, 1/4 and 1/2 MIC) of five antibiotics (clindamycin, daptomycin, linezolid, tigecycline and vancomycin). After 4 and 6 h of incubation, culture pellets were used for relative quantitative RT-PCR with primers specific for pvl, hla, spa and gyrB. The PVL, Hla and SpA concentrations were measured in the supernatant (for PVL and Hla) and in the cell pellet (for SpA) using specific ELISAs. RESULTS For all strains tested, clindamycin and linezolid dramatically reduced mRNA levels of PVL and SpA. Tigecycline also decreased the PVL and SpA mRNA levels of 3/5 and 4/5 strains tested, respectively, whereas daptomycin and vancomycin had no significant effect. PVL and SpA quantification confirmed the concentration-dependent inhibition of PVL and SpA production by clindamycin and, to a lesser extent, by linezolid and tigecycline. Only clindamycin decreased Hla mRNA expression, whereas linezolid, tigecycline and daptomycin showed heterogeneous strain-dependent results, and vancomycin had no significant effect. Analysis of the Hla level revealed a stronger concentration-dependent inhibition of Hla release by clindamycin than by linezolid. CONCLUSIONS The effect of sub-MICs on virulence expression depended on the antibiotic and the virulence factor. Clindamycin and linezolid consistently suppressed the expression of different virulence factors by CA-MRSA, whereas tigecycline specifically suppressed PVL expression. Daptomycin and vancomycin seem to have no significant effects at these concentrations.
Collapse
Affiliation(s)
- Marie Pierre Otto
- Centre National de Référence des Staphylocoques, Faculté de Médecine Lyon Est, Université de Lyon, Lyon F-69008, France
| | | | | | | | | | | | | | | | | |
Collapse
|
93
|
Jhas B, Sriskanthadevan S, Skrtic M, Sukhai MA, Voisin V, Jitkova Y, Gronda M, Hurren R, Laister RC, Bader GD, Minden MD, Schimmer AD. Metabolic adaptation to chronic inhibition of mitochondrial protein synthesis in acute myeloid leukemia cells. PLoS One 2013; 8:e58367. [PMID: 23520503 PMCID: PMC3592803 DOI: 10.1371/journal.pone.0058367] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 02/04/2013] [Indexed: 12/19/2022] Open
Abstract
Recently, we demonstrated that the anti-bacterial agent tigecycline preferentially induces death in leukemia cells through the inhibition of mitochondrial protein synthesis. Here, we sought to understand mechanisms of resistance to tigecycline by establishing a leukemia cell line resistant to the drug. TEX leukemia cells were treated with increasing concentrations of tigecycline over 4 months and a population of cells resistant to tigecycline (RTEX+TIG) was selected. Compared to wild type cells, RTEX+TIG cells had undetectable levels of mitochondrially translated proteins Cox-1 and Cox-2, reduced oxygen consumption and increased rates of glycolysis. Moreover, RTEX+TIG cells were more sensitive to inhibitors of glycolysis and more resistant to hypoxia. By electron microscopy, RTEX+TIG cells had abnormally swollen mitochondria with irregular cristae structures. RNA sequencing demonstrated a significant over-representation of genes with binding sites for the HIF1α:HIF1β transcription factor complex in their promoters. Upregulation of HIF1α mRNA and protein in RTEX+TIG cells was confirmed by Q-RTPCR and immunoblotting. Strikingly, upon removal of tigecycline from RTEX+TIG cells, the cells re-established aerobic metabolism. Levels of Cox-1 and Cox-2, oxygen consumption, glycolysis, mitochondrial mass and mitochondrial membrane potential returned to wild type levels, but HIF1α remained elevated. However, upon re-treatment with tigecycline for 72 hours, the glycolytic phenotype was re-established. Thus, we have generated cells with a reversible metabolic phenotype by chronic treatment with an inhibitor of mitochondrial protein synthesis. These cells will provide insight into cellular adaptations used to cope with metabolic stress.
Collapse
MESH Headings
- Anti-Bacterial Agents/pharmacology
- Cell Line, Tumor
- Drug Resistance, Neoplasm
- Electron Transport Complex IV/biosynthesis
- Electron Transport Complex IV/genetics
- Gene Expression Regulation, Leukemic/drug effects
- Gene Expression Regulation, Leukemic/genetics
- Glycolysis/drug effects
- Glycolysis/genetics
- Humans
- Hypoxia-Inducible Factor 1, alpha Subunit/biosynthesis
- Hypoxia-Inducible Factor 1, alpha Subunit/genetics
- Leukemia, Myeloid, Acute/drug therapy
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myeloid, Acute/metabolism
- Leukemia, Myeloid, Acute/pathology
- Minocycline/analogs & derivatives
- Minocycline/pharmacology
- Mitochondrial Proteins/biosynthesis
- Mitochondrial Proteins/genetics
- Neoplasm Proteins/biosynthesis
- Neoplasm Proteins/genetics
- Oxygen Consumption/drug effects
- Oxygen Consumption/genetics
- Protein Biosynthesis
- Tigecycline
Collapse
Affiliation(s)
- Bozhena Jhas
- The Princess Margaret Hospital and The Ontario Cancer Institute, University Health Network, Toronto, Canada
| | - Shrivani Sriskanthadevan
- The Princess Margaret Hospital and The Ontario Cancer Institute, University Health Network, Toronto, Canada
| | - Marko Skrtic
- The Princess Margaret Hospital and The Ontario Cancer Institute, University Health Network, Toronto, Canada
| | - Mahadeo A. Sukhai
- The Princess Margaret Hospital and The Ontario Cancer Institute, University Health Network, Toronto, Canada
| | | | - Yulia Jitkova
- The Princess Margaret Hospital and The Ontario Cancer Institute, University Health Network, Toronto, Canada
| | - Marcela Gronda
- The Princess Margaret Hospital and The Ontario Cancer Institute, University Health Network, Toronto, Canada
| | - Rose Hurren
- The Princess Margaret Hospital and The Ontario Cancer Institute, University Health Network, Toronto, Canada
| | - Rob C. Laister
- The Princess Margaret Hospital and The Ontario Cancer Institute, University Health Network, Toronto, Canada
| | - Gary D. Bader
- The Donnelly Centre, University of Toronto, Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Mark D. Minden
- The Princess Margaret Hospital and The Ontario Cancer Institute, University Health Network, Toronto, Canada
| | - Aaron D. Schimmer
- The Princess Margaret Hospital and The Ontario Cancer Institute, University Health Network, Toronto, Canada
- * E-mail:
| |
Collapse
|
94
|
Structural basis for potent inhibitory activity of the antibiotic tigecycline during protein synthesis. Proc Natl Acad Sci U S A 2013; 110:3812-6. [PMID: 23431179 DOI: 10.1073/pnas.1216691110] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Here we present an X-ray crystallography structure of the clinically relevant tigecycline antibiotic bound to the 70S ribosome. Our structural and biochemical analysis indicate that the enhanced potency of tigecycline results from a stacking interaction with nucleobase C1054 within the decoding site of the ribosome. Single-molecule fluorescence resonance energy transfer studies reveal that, during decoding, tigecycline inhibits the initial codon recognition step of tRNA accommodation and prevents rescue by the tetracycline-resistance protein TetM.
Collapse
|
95
|
Stein GE, Babinchak T. Tigecycline: an update. Diagn Microbiol Infect Dis 2013; 75:331-6. [PMID: 23357291 DOI: 10.1016/j.diagmicrobio.2012.12.004] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 12/10/2012] [Accepted: 12/18/2012] [Indexed: 01/05/2023]
Abstract
Tigecycline is a broad-spectrum antibiotic with activity against difficult-to-treat pathogens such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus spp., Acinetobacter baumannii, and Gram-negative bacterial strains that produce extended-spectrum β-lactamases. Minimal organ toxicity and lack of dosage adjustment in most patients are important considerations for tigecycline use. Tigecycline has been shown to be as effective and safe as standard antimicrobial therapy for treatment of adults with complicated intra-abdominal infections, complicated skin and skin structure infections, and community-acquired bacterial pneumonia. The clearest applications of tigecycline are for on-label indications. Whether tigecycline should be utilized as therapy for other infections including hospital-acquired infections with a high likelihood of multidrug-resistant pathogens is a complex issue that requires ongoing assessment. This article offers an updated overview of tigecycline clinical studies, current microbial resistance patterns, pharmacokinetic/pharmacodynamic investigations, and safety analyses.
Collapse
Affiliation(s)
- Gary E Stein
- Michigan State University, East Lansing, MI 48824, USA.
| | | |
Collapse
|
96
|
Abstract
Ribosome protection proteins (RPPs) confer tetracycline resistance by binding to the ribosome and chasing the drug from its binding site. The current model for the mechanism of action of RPPs proposes that drug release is indirect and achieved via conformational changes within the drug-binding site induced upon binding of the RPP to the ribosome. Here we report a cryo-EM structure of the RPP TetM in complex with the 70S ribosome at 7.2-Å resolution. The structure reveals the contacts of TetM with the ribosome, including interaction between the conserved and functionally critical C-terminal extension of TetM and the decoding center of the small subunit. Moreover, we observe direct interaction between domain IV of TetM and the tetracycline binding site and identify residues critical for conferring tetracycline resistance. A model is presented whereby TetM directly dislodges tetracycline to confer resistance.
Collapse
|
97
|
Brown-Elliott BA, Nash KA, Wallace RJ. Antimicrobial susceptibility testing, drug resistance mechanisms, and therapy of infections with nontuberculous mycobacteria. Clin Microbiol Rev 2012; 25:545-82. [PMID: 22763637 PMCID: PMC3416486 DOI: 10.1128/cmr.05030-11] [Citation(s) in RCA: 335] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Within the past 10 years, treatment and diagnostic guidelines for nontuberculous mycobacteria have been recommended by the American Thoracic Society (ATS) and the Infectious Diseases Society of America (IDSA). Moreover, the Clinical and Laboratory Standards Institute (CLSI) has published and recently (in 2011) updated recommendations including suggested antimicrobial and susceptibility breakpoints. The CLSI has also recommended the broth microdilution method as the gold standard for laboratories performing antimicrobial susceptibility testing of nontuberculous mycobacteria. This article reviews the laboratory, diagnostic, and treatment guidelines together with established and probable drug resistance mechanisms of the nontuberculous mycobacteria.
Collapse
|
98
|
Daptomycin and tigecycline have broader effective dose ranges than vancomycin as prophylaxis against a Staphylococcus aureus surgical implant infection in mice. Antimicrob Agents Chemother 2012; 56:2590-7. [PMID: 22371896 DOI: 10.1128/aac.06291-11] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Vancomycin is widely used for intravenous prophylaxis against surgical implant infections. However, it is unclear whether alternative antibiotics used to treat methicillin-resistant Staphylococcus aureus (MRSA) infections are effective as prophylactic agents. The aim of this study was to compare the efficacies of vancomycin, daptomycin, and tigecycline as prophylactic therapy against a methicillin-sensitive S. aureus (MSSA) or MRSA surgical implant infection in mice. MSSA or MRSA was inoculated into the knee joints of mice in the presence of a surgically placed medical-grade metallic implant. The efficacies of low- versus high-dose vancomycin (10 versus 110 mg/kg), daptomycin (1 versus 10 mg/kg), and tigecycline (1 versus 10 mg/kg) intravenous prophylaxis were compared using in vivo bioluminescence imaging, ex vivo bacterial counts, and biofilm formation. High-dose vancomycin, daptomycin, and tigecycline resulted in similar reductions in bacterial burden and biofilm formation. In contrast, low-dose daptomycin and tigecycline were more effective than low-dose vancomycin against the implant infection. In this mouse model of surgical implant MSSA or MRSA infection, daptomycin and tigecycline prophylaxis were effective over a broader dosage range than vancomycin. Future studies in humans will be required to determine whether these broader effective dose ranges for daptomycin and tigecycline in mice translate to improved efficacy in preventing surgical implant infections in clinical practice.
Collapse
|
99
|
Target- and resistance-based mechanistic studies with TP-434, a novel fluorocycline antibiotic. Antimicrob Agents Chemother 2012; 56:2559-64. [PMID: 22354310 DOI: 10.1128/aac.06187-11] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
TP-434 is a novel, broad-spectrum fluorocycline antibiotic with activity against bacteria expressing major antibiotic resistance mechanisms, including tetracycline-specific efflux and ribosomal protection. The mechanism of action of TP-434 was assessed using both cell-based and in vitro assays. In Escherichia coli cells expressing recombinant tetracycline resistance genes, the MIC of TP-434 (0.063 μg/ml) was unaffected by tet(M), tet(K), and tet(B) and increased to 0.25 and 4 μg/ml in the presence of tet(A) and tet(X), respectively. Tetracycline, in contrast, was significantly less potent (MIC ≥ 128 μg/ml) against E. coli cells when any of these resistance mechanisms were present. TP-434 showed potent inhibition in E. coli in vitro transcription/translation (50% inhibitory concentration [IC(50)] = 0.29 ± 0.09 μg/ml) and [(3)H]tetracycline ribosome-binding competition (IC(50) = 0.22 ± 0.07 μM) assays. The antibacterial potencies of TP-434 and all other tetracycline class antibiotics tested were reduced by 4- to 16-fold, compared to that of the wild-type control strain, against Propionibacterium acnes strains carrying a 16S rRNA mutation, G1058C, a modification that changes the conformation of the primary binding site of tetracycline in the ribosome. Taken together, the findings support the idea that TP-434, like other tetracyclines, binds the ribosome and inhibits protein synthesis and that this activity is largely unaffected by the common tetracycline resistance mechanisms.
Collapse
|
100
|
Xiao XY, Hunt DK, Zhou J, Clark RB, Dunwoody N, Fyfe C, Grossman TH, O'Brien WJ, Plamondon L, Rönn M, Sun C, Zhang WY, Sutcliffe JA. Fluorocyclines. 1. 7-fluoro-9-pyrrolidinoacetamido-6-demethyl-6-deoxytetracycline: a potent, broad spectrum antibacterial agent. J Med Chem 2012; 55:597-605. [PMID: 22148514 DOI: 10.1021/jm201465w] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This and the accompanying report (DOI: 10.1021/jm201467r ) describe the design, synthesis, and evaluation of a new generation of tetracycline antibacterial agents, 7-fluoro-9-substituted-6-demethyl-6-deoxytetracyclines ("fluorocyclines"), accessible through a recently developed total synthesis approach. These fluorocyclines possess potent antibacterial activities against multidrug resistant (MDR) Gram-positive and Gram-negative pathogens. One of the fluorocyclines, 7-fluoro-9-pyrrolidinoacetamido-6-demethyl-6-deoxytetracycline (17j, also known as TP-434, 50th Interscience Conference on Antimicrobial Agents and Chemotherapy Conference , Boston, MA , September 12-15, 2010 , poster F1 - 2157 ), is currently undergoing phase 2 clinical trials in patients with complicated intra-abdominal infections (cIAI).
Collapse
Affiliation(s)
- Xiao-Yi Xiao
- Discovery Chemistry, Tetraphase Pharmaceuticals, 480 Arsenal Street, Watertown, Massachusetts 02472, United States.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|