1
|
Lee CC, Lai CH, Yang CH, Huang YH, Lin JN. Antibiotic Combination to Effectively Postpone or Inhibit the In Vitro Induction and Selection of Levofloxacin-Resistant Mutants in Elizabethkingia anophelis. Int J Mol Sci 2024; 25:2215. [PMID: 38396892 PMCID: PMC10889675 DOI: 10.3390/ijms25042215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 02/07/2024] [Accepted: 02/11/2024] [Indexed: 02/25/2024] Open
Abstract
Fluoroquinolones are potentially active against Elizabethkingia anophelis. Rapidly increased minimum inhibitory concentrations (MICs) and emerging point mutations in the quinolone resistance-determining regions (QRDRs) following exposure to fluoroquinolones have been reported in E. anophelis. We aimed to investigate point mutations in QRDRs through exposure to levofloxacin (1 × MIC) combinations with different concentrations (0.5× and 1 × MIC) of minocycline, rifampin, cefoperazone/sulbactam, or sulfamethoxazole/trimethoprim in comparison with exposure to levofloxacin alone. Of the four E. anophelis isolates that were clinically collected, lower MICs of levofloxacin were disclosed in cycle 2 and 3 of induction and selection in all levofloxacin combination groups other than levofloxacin alone (all p = 0.04). Overall, no mutations were discovered in parC and parE throughout the multicycles inducted by levofloxacin and all its combinations. Regarding the vastly increased MICs, the second point mutations in gyrA and/or gyrB in one isolate (strain no. 1) occurred in cycle 2 following exposure to levofloxacin plus 0.5 × MIC minocycline, but they were delayed appearing in cycle 5 following exposure to levofloxacin plus 1 × MIC minocycline. Similarly, the second point mutation in gyrA and/or gyrB occurred in another isolate (strain no. 3) in cycle 4 following exposure to levofloxacin plus 0.5 × MIC sulfamethoxazole/trimethoprim, but no mutation following exposure to levofloxacin plus 1 × MIC sulfamethoxazole/trimethoprim was disclosed. In conclusion, the rapid selection of E. anophelis mutants with high MICs after levofloxacin exposure could be effectively delayed or postponed by antimicrobial combination with other in vitro active antibiotics.
Collapse
Affiliation(s)
- Ching-Chi Lee
- Clinical Medical Research Center, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan;
- Departments of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
| | - Chung-Hsu Lai
- School of Medicine, College of Medicine, I-Shou University, Kaohsiung 824, Taiwan; (C.-H.L.); (Y.-H.H.)
- Division of Infectious Diseases, Department of Internal Medicine, E-Da Hospital, I-Shou University, Kaohsiung 824, Taiwan
| | - Chih-Hui Yang
- Department of Biological Science and Technology, Meiho University, Pingtung 912, Taiwan;
| | - Yi-Han Huang
- School of Medicine, College of Medicine, I-Shou University, Kaohsiung 824, Taiwan; (C.-H.L.); (Y.-H.H.)
- Division of Infectious Diseases, Department of Internal Medicine, E-Da Hospital, I-Shou University, Kaohsiung 824, Taiwan
| | - Jiun-Nong Lin
- School of Medicine, College of Medicine, I-Shou University, Kaohsiung 824, Taiwan; (C.-H.L.); (Y.-H.H.)
- Division of Infectious Diseases, Department of Internal Medicine, E-Da Hospital, I-Shou University, Kaohsiung 824, Taiwan
- Department of Critical Care Medicine, E-Da Hospital, I-Shou University, Kaohsiung 824, Taiwan
| |
Collapse
|
2
|
Li Y, Feng J, Huang F, Baell JB. Synthesis of 3-Azabicyclo[3.1.0]hexane Derivates. Chemistry 2023; 29:e202301017. [PMID: 37269044 DOI: 10.1002/chem.202301017] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/28/2023] [Accepted: 06/02/2023] [Indexed: 06/04/2023]
Abstract
3-Azabicyclo[3.1.0]hexanes are an important class of nitrogen-containing heterocycles that have been found to be key structural features in a wide range of biologically active natural products, drugs, and agrochemicals. As a cutting-edge area, the synthesis of these derivatives has made spectacular progress in recent decades, with various transition-metal-catalyzed and transition-metal-free catalytic systems being developed. In this review, we provide an overview of recent advances in the efficient methods for the synthesis of 3-azabicyclo[3.1.0]hexane derivatives since 2010, emphasizing the scope of substrates and synthesis' applications, as well as the mechanisms of these reactions.
Collapse
Affiliation(s)
- Yufeng Li
- School of Pharmaceutical Sciences, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, Jiangsu, 211816, China
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, No.1 Wenyuan Road, Nanjing, Jiangsu, 210023, China
| | - Jiajun Feng
- School of Pharmaceutical Sciences, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, Jiangsu, 211816, China
| | - Fei Huang
- School of Pharmaceutical Sciences, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, Jiangsu, 211816, China
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, No.1 Wenyuan Road, Nanjing, Jiangsu, 210023, China
| | - Jonathan B Baell
- School of Pharmaceutical Sciences, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, Jiangsu, 211816, China
| |
Collapse
|
3
|
Li T, Wang Z, Guo J, de la Fuente-Nunez C, Wang J, Han B, Tao H, Liu J, Wang X. Bacterial resistance to antibacterial agents: Mechanisms, control strategies, and implications for global health. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 860:160461. [PMID: 36435256 DOI: 10.1016/j.scitotenv.2022.160461] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 11/19/2022] [Accepted: 11/20/2022] [Indexed: 06/16/2023]
Abstract
The spread of bacterial drug resistance has posed a severe threat to public health globally. Here, we cover bacterial resistance to current antibacterial drugs, including traditional herbal medicines, conventional antibiotics, and antimicrobial peptides. We summarize the influence of bacterial drug resistance on global health and its economic burden while highlighting the resistance mechanisms developed by bacteria. Based on the One Health concept, we propose 4A strategies to combat bacterial resistance, including prudent Application of antibacterial agents, Administration, Assays, and Alternatives to antibiotics. Finally, we identify several opportunities and unsolved questions warranting future exploration for combating bacterial resistance, such as predicting genetic bacterial resistance through the use of more effective techniques, surveying both genetic determinants of bacterial resistance and the transmission dynamics of antibiotic resistance genes (ARGs).
Collapse
Affiliation(s)
- Ting Li
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China; State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, No. 20, Dongda Street, Fengtai District, Beijing 100071, PR China
| | - Zhenlong Wang
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China
| | - Jianhua Guo
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St Lucia, Queensland 4072, Australia.
| | - Cesar de la Fuente-Nunez
- Machine Biology Group, Departments of Psychiatry and Microbiology, Institute for Biomedical Informatics, Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America; Departments of Bioengineering and Chemical and Biomolecular Engineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, United States of America; Penn Institute for Computational Science, University of Pennsylvania, Philadelphia, PA, United States of America.
| | - Jinquan Wang
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China
| | - Bing Han
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China
| | - Hui Tao
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China
| | - Jie Liu
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China
| | - Xiumin Wang
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China.
| |
Collapse
|
4
|
Li Q, Zhang Y, Liu P, Zhong J, Gong B, Yao H, Lin A. Pd-Catalyzed Asymmetric 5-exo-trig Cyclization/Cyclopropanation/Carbonylation of 1,6-Enynes for the Construction of Chiral 3-Azabicyclo[3.1.0]hexanes. Angew Chem Int Ed Engl 2023; 62:e202211988. [PMID: 36426561 DOI: 10.1002/anie.202211988] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 11/01/2022] [Accepted: 11/23/2022] [Indexed: 11/26/2022]
Abstract
We herein disclose a mild and efficient access to chiral 3-azabicyclo[3.1.0]hexanes via a Pd-catalyzed asymmetric 5-exo-trig cyclization/cyclopropanation/carbonylation of 1,6-enynes. Various nucleophiles, such as alcohols, phenols, amines and water, are well compatible with the reaction system. This reaction forms three C-C bonds, two rings, two adjacent quaternary carbon stereocenters as well as one C-O/C-N bond with excellent regio- and enantioselectivities. The products could be further functionalized to generate a library of 3-azabicyclo[3.1.0]hexane frameworks.
Collapse
Affiliation(s)
- Qiuyu Li
- State Key Laboratory of Natural Medicines (SKLNM) and Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, P. R. China
| | - Yunchu Zhang
- State Key Laboratory of Natural Medicines (SKLNM) and Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, P. R. China
| | - Pengyun Liu
- State Key Laboratory of Natural Medicines (SKLNM) and Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, P. R. China
| | - Jing Zhong
- State Key Laboratory of Natural Medicines (SKLNM) and Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, P. R. China
| | - Baihui Gong
- State Key Laboratory of Natural Medicines (SKLNM) and Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, P. R. China
| | - Hequan Yao
- State Key Laboratory of Natural Medicines (SKLNM) and Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, P. R. China
| | - Aijun Lin
- State Key Laboratory of Natural Medicines (SKLNM) and Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, P. R. China
| |
Collapse
|
5
|
Dolna M, Nowacki M, Danylyuk O, Brotons-Rufes A, Poater A, Michalak M. NHC-BIAN-Cu(I)-Catalyzed Friedländer-Type Annulation of 2-Amino-3-(per)fluoroacetylpyridines with Alkynes on Water. J Org Chem 2022; 87:6115-6136. [PMID: 35394784 PMCID: PMC9087358 DOI: 10.1021/acs.joc.2c00380] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
![]()
The direct catalytic
alkynylation/dehydrative cyclization of 2-amino-3-trifluoroacetyl-pyridines
on water was developed for the efficient synthesis of a broad range
of fluorinated 1,8-naphthyridines from terminal alkynes. A novel N-heterocyclic
carbene (NHC) ligand system that combines a π-extended acenaphthylene
backbone with sterically bulky pentiptycene pendant groups was successfully
utilized in a copper- or silver-mediated cyclization. Computational
analysis of the reaction pathway supports our explanation of the different
experimental conversions and yields for the set of copper and silver
catalysts. The impact of steric hindrance at the metal center and
the flexibility of substituents on the imidazole ring of the NHC on
catalytic performance are also discussed.
Collapse
Affiliation(s)
- Magdalena Dolna
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Michał Nowacki
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Oksana Danylyuk
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Artur Brotons-Rufes
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, c/ M. Aurèlia Capmany 69, 17003 Girona, Catalonia, Spain
| | - Albert Poater
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, c/ M. Aurèlia Capmany 69, 17003 Girona, Catalonia, Spain
| | - Michał Michalak
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| |
Collapse
|
6
|
Merey G, Kubilay HN, Anac O. CuCl/AgSbF 6and Rh 2(OAc) 4Comparison for the Synthesis of N-O Tethered Three and Five Membered Rings via Diazo Chemistry. CHEM LETT 2021. [DOI: 10.1246/cl.200863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Gokce Merey
- Chemical Engineering Department, Hitit University Kuzey Campus, Corum 19030 Turkey
| | - H. Nur Kubilay
- Chemistry Department, Istanbul Technical University Ayazaga Campus, Maslak/Istanbul 34467 Turkey
| | - Olcay Anac
- Chemistry Department, Istanbul Technical University Ayazaga Campus, Maslak/Istanbul 34467 Turkey
| |
Collapse
|
7
|
Ahn JH, Jegal H, Choi MS, Kim S, Park SM, Ahn J, Han HY, Cho HS, Yoon S, Oh JH. TNFα enhances trovafloxacin-induced in vitro hepatotoxicity by inhibiting protective autophagy. Toxicol Lett 2021; 342:73-84. [PMID: 33609687 DOI: 10.1016/j.toxlet.2021.02.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 02/09/2021] [Accepted: 02/12/2021] [Indexed: 12/12/2022]
Abstract
Trovafloxacin (TVX) is associated with idiosyncratic drug-induced liver injury (iDILI) and inflammation-mediated hepatotoxicity. However, the inflammatory stress-regulated mechanisms in iDILI remain unclear. Herein, we elucidated the novel role of tumor-necrosis factor alpha (TNFα), an inflammatory stress factor, in TVX-induced in vitro hepatotoxicity and synergistic toxicity. TVX specifically induced synergistic toxicity in HepG2 cells with TNFα, which inhibits autophagy. TVX-treated HepG2 cells induced protective autophagy by inhibiting the expression of mTOR signaling proteins, while ATG5 knockdown in HepG2 cells, responsible for the impairment of autophagy, enhanced TVX-induced toxicity due to the increase in cytochrome C release and JNK pathway activation. Interestingly, the expression of mTOR signal proteins, which were suppressed by TVX, disrupted the negative feedback of the PI3K/AKT pathway and TNFα rebounded p70S6K phosphorylation. Co-treatment with TVX and TNFα inhibited protective autophagy by maintaining p70S6K activity, which enhanced TVX-induced cytotoxicity. Phosphorylation of p70S6K was inhibited by siRNA knockdown and rapamycin to restore TNFα-inhibited autophagy, which prevented the synergistic effect on TVX-induced cytotoxicity. These results indicate that TVX activates protective autophagy in HepG2 cells exposed to toxicity and an imbalance in negative feedback regulation of autophagy by TNFα synergistically enhanced the toxicity. The finding from this study may contribute to a better understanding of the mechanisms underlying iDILI associated with inflammatory stress.
Collapse
Affiliation(s)
- Jun-Ho Ahn
- Department of Predictive Toxicology, Korea Institute of Toxicology, 141 Gajeong-ro, Yuseong-gu, Daejeon, 34114, Republic of Korea; Bio Medical Research Center, Bio Medical & Health Division, Korea Testing Laboratory (KTL), Seoul, 08389, Republic of Korea
| | - Hyun Jegal
- Department of Predictive Toxicology, Korea Institute of Toxicology, 141 Gajeong-ro, Yuseong-gu, Daejeon, 34114, Republic of Korea; Department of Human and Environmental Toxicology, University of Science & Technology, Daejeon, 34113, Republic of Korea
| | - Mi-Sun Choi
- Department of Predictive Toxicology, Korea Institute of Toxicology, 141 Gajeong-ro, Yuseong-gu, Daejeon, 34114, Republic of Korea
| | - Soojin Kim
- Department of Predictive Toxicology, Korea Institute of Toxicology, 141 Gajeong-ro, Yuseong-gu, Daejeon, 34114, Republic of Korea
| | - Se-Myo Park
- Department of Predictive Toxicology, Korea Institute of Toxicology, 141 Gajeong-ro, Yuseong-gu, Daejeon, 34114, Republic of Korea
| | - Jaehwan Ahn
- Department of Predictive Toxicology, Korea Institute of Toxicology, 141 Gajeong-ro, Yuseong-gu, Daejeon, 34114, Republic of Korea
| | - Hyoung-Yun Han
- Department of Predictive Toxicology, Korea Institute of Toxicology, 141 Gajeong-ro, Yuseong-gu, Daejeon, 34114, Republic of Korea
| | - Hyun-Soo Cho
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Republic of Korea
| | - Seokjoo Yoon
- Department of Predictive Toxicology, Korea Institute of Toxicology, 141 Gajeong-ro, Yuseong-gu, Daejeon, 34114, Republic of Korea; Department of Human and Environmental Toxicology, University of Science & Technology, Daejeon, 34113, Republic of Korea.
| | - Jung-Hwa Oh
- Department of Predictive Toxicology, Korea Institute of Toxicology, 141 Gajeong-ro, Yuseong-gu, Daejeon, 34114, Republic of Korea; Department of Human and Environmental Toxicology, University of Science & Technology, Daejeon, 34113, Republic of Korea.
| |
Collapse
|
8
|
Xu H, Han T, Luo X, Deng W. Construction of
3‐Azabicyclo
[3.1.0]hexane Backbone by the Reaction of Allenes with Allylamines
via
Tandem Michael Addition and
Copper‐Mediated
Oxidative Carbanion Cyclization. CHINESE J CHEM 2021. [DOI: 10.1002/cjoc.202000405] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Hui Xu
- Shanghai Key Laboratory of New Drug Design and School of Pharmacy, East China University of Science and Technology 130 Meilong Road Shanghai 200237 China
| | - Teng Han
- Shanghai Key Laboratory of New Drug Design and School of Pharmacy, East China University of Science and Technology 130 Meilong Road Shanghai 200237 China
| | - Xiaoyan Luo
- Shanghai Key Laboratory of New Drug Design and School of Pharmacy, East China University of Science and Technology 130 Meilong Road Shanghai 200237 China
| | - Wei‐Ping Deng
- Shanghai Key Laboratory of New Drug Design and School of Pharmacy, East China University of Science and Technology 130 Meilong Road Shanghai 200237 China
| |
Collapse
|
9
|
Bąchor U, Mączyński M. Selected β 2-, β 3- and β 2,3-Amino Acid Heterocyclic Derivatives and Their Biological Perspective. Molecules 2021; 26:438. [PMID: 33467741 PMCID: PMC7829935 DOI: 10.3390/molecules26020438] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 01/10/2021] [Accepted: 01/12/2021] [Indexed: 11/25/2022] Open
Abstract
Heterocyclic moieties, especially five and six-membered rings containing nitrogen, oxygen or sulfur atoms, are broadly distributed in nature. Among them, synthetic and natural alike are pharmacologically active compounds and have always been at the forefront of attention due to their pharmacological properties. Heterocycles can be divided into different groups based on the presence of characteristic structural motifs. The presence of β-amino acid and heterocyclic core in one compound is very interesting; additionally, it very often plays a vital role in their biological activity. Usually, such compounds are not considered to be chemicals containing a β-amino acid motif; however, considering them as this class of compounds may open new routes of their preparation and application as new drug precursors or even drugs. The possibility of their application as nonproteinogenic amino acid residues in peptide or peptide derivatives synthesis to prepare a new class of compounds is also promising. This review highlights the actual state of knowledge about β-amino acid moiety-containing heterocycles presenting antiviral, anti-inflammatory, antibacterial compounds, anaplastic lymphoma kinase (ALK) inhibitors, as well as agonist and antagonists of the receptors.
Collapse
Affiliation(s)
- Urszula Bąchor
- Department of Organic Chemistry, Faculty of Pharmacy, Wroclaw Medical University, 50-556 Wroclaw, Poland;
| | | |
Collapse
|
10
|
Huang X, Nguyen MH, Pu M, Zhang L, Chi YR, Wu Y, Zhou JS. Asymmetric Reductive and Alkynylative Heck Bicyclization of Enynes to Access Conformationally Restricted Aza[3.1.0]bicycles. Angew Chem Int Ed Engl 2020; 59:10814-10818. [DOI: 10.1002/anie.202000859] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Indexed: 12/11/2022]
Affiliation(s)
- Xiaolei Huang
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link 637371 Singapore Singapore
| | - Minh Hieu Nguyen
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link 637371 Singapore Singapore
| | - Maoping Pu
- Shenzhen Bay Laboratory Shenzhen 518055 China
| | - Luoqiang Zhang
- State Key Laboratory of Chemical OncogenomicsKey Laboratory of Chemical GenomicsSchool of Chemical Biology and BiotechnologyPeking University Shenzhen Graduate School 2199 Lishui Road, Room F312 Nanshan District Shenzhen 518055 China
| | - Yonggui Robin Chi
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link 637371 Singapore Singapore
| | - Yun‐Dong Wu
- Lab of Computational Chemistry and Drug DesignState Key Laboratory of Chemical OncogenomicsPeking University Shenzhen Graduate SchoolShenzhen Bay Laboratory Shenzhen 518055 China
| | - Jianrong Steve Zhou
- State Key Laboratory of Chemical OncogenomicsKey Laboratory of Chemical GenomicsSchool of Chemical Biology and BiotechnologyPeking University Shenzhen Graduate School 2199 Lishui Road, Room F312 Nanshan District Shenzhen 518055 China
| |
Collapse
|
11
|
Huang X, Nguyen MH, Pu M, Zhang L, Chi YR, Wu Y, Zhou JS. Asymmetric Reductive and Alkynylative Heck Bicyclization of Enynes to Access Conformationally Restricted Aza[3.1.0]bicycles. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202000859] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Xiaolei Huang
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link 637371 Singapore Singapore
| | - Minh Hieu Nguyen
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link 637371 Singapore Singapore
| | - Maoping Pu
- Shenzhen Bay Laboratory Shenzhen 518055 China
| | - Luoqiang Zhang
- State Key Laboratory of Chemical OncogenomicsKey Laboratory of Chemical GenomicsSchool of Chemical Biology and BiotechnologyPeking University Shenzhen Graduate School 2199 Lishui Road, Room F312 Nanshan District Shenzhen 518055 China
| | - Yonggui Robin Chi
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link 637371 Singapore Singapore
| | - Yun‐Dong Wu
- Lab of Computational Chemistry and Drug DesignState Key Laboratory of Chemical OncogenomicsPeking University Shenzhen Graduate SchoolShenzhen Bay Laboratory Shenzhen 518055 China
| | - Jianrong Steve Zhou
- State Key Laboratory of Chemical OncogenomicsKey Laboratory of Chemical GenomicsSchool of Chemical Biology and BiotechnologyPeking University Shenzhen Graduate School 2199 Lishui Road, Room F312 Nanshan District Shenzhen 518055 China
| |
Collapse
|
12
|
Ren X, Chandgude AL, Fasan R. Highly Stereoselective Synthesis of Fused Cyclopropane-γ-Lactams via Biocatalytic Iron-Catalyzed Intramolecular Cyclopropanation. ACS Catal 2020; 10:2308-2313. [PMID: 32257580 PMCID: PMC7111458 DOI: 10.1021/acscatal.9b05383] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We report the development of an iron-based biocatalytic strategy for the asymmetric synthesis of fused cyclopropane-γ-lactams, which are key structural motifs found in synthetic drugs and bioactive natural products. Using a combination of mutational landscape and iterative site-saturation mutagenesis, sperm whale myoglobin was evolved into a biocatalyst capable of promoting the cyclization of a diverse range of allyl diazoacetamide substrates into the corresponding bicyclic lactams in high yields and with high enantioselectivity (up to 99% ee). These biocatalytic transformations can be performed in whole cells and could be leveraged to enable the efficient (chemo)enzymatic construction of chiral cyclopropane-γ-lactams as well as β-cyclopropyl amines and cyclopropane-fused pyrrolidines, as valuable building blocks and synthons for medicinal chemistry and natural product synthesis.
Collapse
Affiliation(s)
| | | | - Rudi Fasan
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY 14627, United States
| |
Collapse
|
13
|
Diaz J, Rodenas D, Ballester FJ, Alajarin M, Orenes RA, Sanchez-Andrada P, Vidal A. Unlocking the synthetic potential of aziridine and cyclopropane-fused quinolin-2-ones by regioselective fragmentation of its three-membered rings. ARAB J CHEM 2020. [DOI: 10.1016/j.arabjc.2018.07.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|
14
|
Garg C, Seo JH, Ramachandran J, Loh JM, Calderon F, Contreras JE. Trovafloxacin attenuates neuroinflammation and improves outcome after traumatic brain injury in mice. J Neuroinflammation 2018; 15:42. [PMID: 29439712 PMCID: PMC5812039 DOI: 10.1186/s12974-018-1069-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 01/17/2018] [Indexed: 12/20/2022] Open
Abstract
Background Trovafloxacin is a broad-spectrum antibiotic, recently identified as an inhibitor of pannexin-1 (Panx1) channels. Panx1 channels are important conduits for the adenosine triphosphate (ATP) release from live and dying cells that enhances the inflammatory response of immune cells. Elevated extracellular levels ATP released upon injury activate purinergic pathways in inflammatory cells that promote migration, proliferation, phagocytosis, and apoptotic signals. Here, we tested whether trovafloxacin administration attenuates the neuroinflammatory response and improves outcomes after brain trauma. Methods The murine controlled cortical impact (CCI) model was used to determine whether in vivo delivery of trovafloxacin has anti-inflammatory and neuroprotective actions after brain trauma. Locomotor deficit was assessed using the rotarod test. Levels of tissue damage markers and inflammation were measured using western blot, qPCR, and immunofluorescence. In vitro assays were used to evaluate whether trovafloxacin blocks ATP release and cell migration in a chemotactic-stimulated microglia cell line. Results Trovafloxacin treatment of CCI-injured mice significantly reduced tissue damage markers and improved locomotor deficits. In addition, trovafloxacin treatment significantly reduced mRNA levels of several pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), which correlates with an overall reduction in the accumulation of inflammatory cell types (neutrophils, microglia/macrophages, and astroglia) at the injury zone. To determine whether trovafloxacin exerted these effects by direct action on immune cells, we evaluated its effect on ATP release and cell migration using a chemotactic-stimulated microglial cell line. We found that trovafloxacin significantly inhibited both ATP release and migration of these cells. Conclusion Our results show that trovafloxacin administration has pronounced anti-inflammatory and neuroprotective effects following brain injury. These findings lay the foundation for future studies to directly test a role for Panx1 channels in pathological inflammation following brain trauma. Electronic supplementary material The online version of this article (10.1186/s12974-018-1069-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Charu Garg
- Department of Pharmacology, Physiology and Neurosciences, New Jersey Medical School, Rutgers University, 185 South Orange Ave, Newark, NJ, 07103, USA
| | - Joon Ho Seo
- Department of Pharmacology, Physiology and Neurosciences, New Jersey Medical School, Rutgers University, 185 South Orange Ave, Newark, NJ, 07103, USA
| | - Jayalakshmi Ramachandran
- Department of Pharmacology, Physiology and Neurosciences, New Jersey Medical School, Rutgers University, 185 South Orange Ave, Newark, NJ, 07103, USA
| | - Ji Meng Loh
- Department of Mathematical Sciences, New Jersey Institute of Technology, University Heights, Newark, NJ, 07102, USA
| | - Frances Calderon
- Department of Pharmacology, Physiology and Neurosciences, New Jersey Medical School, Rutgers University, 185 South Orange Ave, Newark, NJ, 07103, USA.
| | - Jorge E Contreras
- Department of Pharmacology, Physiology and Neurosciences, New Jersey Medical School, Rutgers University, 185 South Orange Ave, Newark, NJ, 07103, USA.
| |
Collapse
|
15
|
Veeranna KD, Das KK, Baskaran S. One-Pot Synthesis of Cyclopropane-Fused Cyclic Amidines: An Oxidative Carbanion Cyclization. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201708138] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Kanak Kanti Das
- Department of Chemistry; Indian Institute of Technology Madras; Chennai- 600036 India
| | - Sundarababu Baskaran
- Department of Chemistry; Indian Institute of Technology Madras; Chennai- 600036 India
| |
Collapse
|
16
|
Veeranna KD, Das KK, Baskaran S. One-Pot Synthesis of Cyclopropane-Fused Cyclic Amidines: An Oxidative Carbanion Cyclization. Angew Chem Int Ed Engl 2017; 56:16197-16201. [DOI: 10.1002/anie.201708138] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Indexed: 02/06/2023]
Affiliation(s)
| | - Kanak Kanti Das
- Department of Chemistry; Indian Institute of Technology Madras; Chennai- 600036 India
| | - Sundarababu Baskaran
- Department of Chemistry; Indian Institute of Technology Madras; Chennai- 600036 India
| |
Collapse
|
17
|
Wang M, Rakesh KP, Leng J, Fang WY, Ravindar L, Channe Gowda D, Qin HL. Amino acids/peptides conjugated heterocycles: A tool for the recent development of novel therapeutic agents. Bioorg Chem 2017; 76:113-129. [PMID: 29169078 DOI: 10.1016/j.bioorg.2017.11.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 11/02/2017] [Accepted: 11/15/2017] [Indexed: 10/18/2022]
Abstract
Amino acids/peptide conjugated heterocycles represent an important class of therapeutical agents. Biologically active heterocycles are conjugated with amino acids or peptides to increase the drug resistance. Furthermore, the amino acid/peptide based drugs have low toxicity, ample bioavailability and permeability, modest potency and good metabolic and pharmacokinetic properties. Synthetic amino acid/peptides based heterocyclic conjugates constitute a promising choice for the development of new, less toxic and safer conventional pharmaceutical drugs in the near future. In this review, we discuss and highlight the recent findings of the structural features that encourage biological applications of amino acid/peptides based conjugates.
Collapse
Affiliation(s)
- Meng Wang
- Department of Pharmaceutical Engineering, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 205 Luoshi Road, Wuhan 430073, PR China
| | - K P Rakesh
- Department of Pharmaceutical Engineering, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 205 Luoshi Road, Wuhan 430073, PR China.
| | - Jing Leng
- Department of Pharmaceutical Engineering, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 205 Luoshi Road, Wuhan 430073, PR China
| | - Wan-Yin Fang
- Department of Pharmaceutical Engineering, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 205 Luoshi Road, Wuhan 430073, PR China
| | - L Ravindar
- Department of Pharmaceutical Engineering, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 205 Luoshi Road, Wuhan 430073, PR China
| | - D Channe Gowda
- Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysuru 570006, Karnataka, India.
| | - Hua-Li Qin
- Department of Pharmaceutical Engineering, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 205 Luoshi Road, Wuhan 430073, PR China.
| |
Collapse
|
18
|
Weaver JL, Arandjelovic S, Brown G, K Mendu S, S Schappe M, Buckley MW, Chiu YH, Shu S, Kim JK, Chung J, Krupa J, Jevtovic-Todorovic V, Desai BN, Ravichandran KS, Bayliss DA. Hematopoietic pannexin 1 function is critical for neuropathic pain. Sci Rep 2017; 7:42550. [PMID: 28195232 PMCID: PMC5307344 DOI: 10.1038/srep42550] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 01/12/2017] [Indexed: 12/13/2022] Open
Abstract
Neuropathic pain symptoms respond poorly to available therapeutics, with most treated patients reporting unrelieved pain and significant impairment in daily life. Here, we show that Pannexin 1 (Panx1) in hematopoietic cells is required for pain-like responses following nerve injury in mice, and a potential therapeutic target. Panx1 knockout mice (Panx1-/-) were protected from hypersensitivity in two sciatic nerve injury models. Bone marrow transplantation studies show that expression of functional Panx1 in hematopoietic cells is necessary for mechanical hypersensitivity following nerve injury. Reconstitution of irradiated Panx1 knockout mice with hematopoietic Panx1-/- cells engineered to re-express Panx1 was sufficient to recover hypersensitivity after nerve injury; this rescue required expression of a Panx1 variant that can be activated by G protein-coupled receptors (GPCRs). Finally, chemically distinct Panx1 inhibitors blocked development of nerve injury-induced hypersensitivity and partially relieved this hypersensitivity after it was established. These studies indicate that Panx1 expressed in immune cells is critical for pain-like effects following nerve injury in mice, perhaps via a GPCR-mediated activation mechanism, and suggest that inhibition of Panx1 may be useful in treating neuropathic pain.
Collapse
Affiliation(s)
- Janelle L Weaver
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Sanja Arandjelovic
- Department of Microbiology, Immunology, Cancer Biology, University of Virginia, Charlottesville, Virginia 22908, USA.,Carter Immunology Center, University of Virginia, Charlottesville, Virginia 22908, USA.,Center for Cell Clearance, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Gregory Brown
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Suresh K Mendu
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Michael S Schappe
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Monica W Buckley
- Department of Microbiology, Immunology, Cancer Biology, University of Virginia, Charlottesville, Virginia 22908, USA.,Carter Immunology Center, University of Virginia, Charlottesville, Virginia 22908, USA.,Center for Cell Clearance, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Yu-Hsin Chiu
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Shaofang Shu
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Jin K Kim
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Joyce Chung
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Julia Krupa
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | | | - Bimal N Desai
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Kodi S Ravichandran
- Department of Microbiology, Immunology, Cancer Biology, University of Virginia, Charlottesville, Virginia 22908, USA.,Carter Immunology Center, University of Virginia, Charlottesville, Virginia 22908, USA.,Center for Cell Clearance, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| |
Collapse
|
19
|
Zhao Q, Yao CS, Wang XS. One-Pot Four-Component Synthesis of 5,10-Diarylpyrido[4,3-b][1,6] Naphthyridine Derivatives in Ionic Liquids Catalyzed by TsOH. Polycycl Aromat Compd 2016. [DOI: 10.1080/10406638.2016.1200635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Qun Zhao
- College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, P. R. China
| | - Chang-Sheng Yao
- School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Green Synthesis for Functional Materials, Jiangsu Normal University, Xuzhou, Jiangsu, P. R. China
| | - Xiang-Shan Wang
- School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Green Synthesis for Functional Materials, Jiangsu Normal University, Xuzhou, Jiangsu, P. R. China
| |
Collapse
|
20
|
Jin RZ, Li YL, Wang XS. An efficient synthesis of 11-aryl-10-oxo-7,8,10,11-tetrahydro-1H-[1,2,3]triazolo [4′,5′:3,4]benzo[1,2-b][1,6]naphthyridine derivatives under catalyst-free conditions. HETEROCYCL COMMUN 2015. [DOI: 10.1515/hc-2015-0050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
AbstractA three-component reaction of an aromatic aldehyde, 1H-benzo[d][1,2,3]triazol-5-amine and tert-butyl 2,4-dioxopiperidine-1-carboxylate in refluxing EtOH under catalyst-free conditions furnishes the title compounds in high yields.
Collapse
Affiliation(s)
- Rong-Zhang Jin
- 1School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials, Jiangsu Normal University, Xuzhou, Jiangsu 221116, P.R. China
| | - Yu-Ling Li
- 1School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials, Jiangsu Normal University, Xuzhou, Jiangsu 221116, P.R. China
| | - Xiang-Shan Wang
- 1School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials, Jiangsu Normal University, Xuzhou, Jiangsu 221116, P.R. China
| |
Collapse
|
21
|
Pedroni J, Saget T, Donets PA, Cramer N. Enantioselective palladium(0)-catalyzed intramolecular cyclopropane functionalization: access to dihydroquinolones, dihydroisoquinolones and the BMS-791325 ring system. Chem Sci 2015; 6:5164-5171. [PMID: 29142735 PMCID: PMC5667185 DOI: 10.1039/c5sc01909e] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 06/17/2015] [Indexed: 01/20/2023] Open
Abstract
Taddol-based phosphoramidite ligands enable enantioselective palladium(0)-catalyzed C-H arylation of cyclopropanes. The cyclized products are obtained in high yields and enantioselectivities. The reported method provides efficient access to a broad range of synthetically attractive cyclopropyl containing dihydroquinolones and dihydroisoquinolones as well as allows for an efficient enantioselective construction of the 7-membered ring of the cyclopropyl indolobenzazepine core of BMS-791325.
Collapse
Affiliation(s)
- J Pedroni
- Laboratory of Asymmetric Catalysis and Synthesis , Institute of Chemical Sciences and Engineering , Ecole Polytechnique Fédérale de Lausanne , EPFL SB ISIC LCSA, BCH 4305 , CH-1015 Lausanne , Switzerland .
| | - T Saget
- Laboratory of Asymmetric Catalysis and Synthesis , Institute of Chemical Sciences and Engineering , Ecole Polytechnique Fédérale de Lausanne , EPFL SB ISIC LCSA, BCH 4305 , CH-1015 Lausanne , Switzerland .
| | - P A Donets
- Laboratory of Asymmetric Catalysis and Synthesis , Institute of Chemical Sciences and Engineering , Ecole Polytechnique Fédérale de Lausanne , EPFL SB ISIC LCSA, BCH 4305 , CH-1015 Lausanne , Switzerland .
| | - N Cramer
- Laboratory of Asymmetric Catalysis and Synthesis , Institute of Chemical Sciences and Engineering , Ecole Polytechnique Fédérale de Lausanne , EPFL SB ISIC LCSA, BCH 4305 , CH-1015 Lausanne , Switzerland .
| |
Collapse
|
22
|
Pedroni J, Cramer N. Chiral γ-Lactams by Enantioselective Palladium(0)-Catalyzed Cyclopropane Functionalizations. Angew Chem Int Ed Engl 2015; 54:11826-9. [PMID: 26271618 DOI: 10.1002/anie.201505916] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Indexed: 01/16/2023]
Abstract
Cyclopropanes fused to pyrrolidines are important structural features found in a number of marketed drugs and development candidates. Typically, their synthesis involves the cyclopropanation of a dihydropyrrole precursor. Reported herein is a complementary approach which employs a palladium(0)-catalyzed C-H functionalization of an achiral cyclopropane to close the pyrrolidine ring in an enantioselective manner. In contrast to aryl-aryl couplings, palladium(0)-catalyzed C-H functionalizations involving the formation of C(sp(3) )-C(sp(3) ) bonds of saturated heterocycles are very scarce. The presented strategy yields cyclopropane-fused γ-lactams from chloroacetamide substrates. A bulky Taddol phosphonite ligand in combination with adamantane-1-carboxylic acid as a cocatalyst provides the γ-lactams in excellent yields and enantioselectivities.
Collapse
Affiliation(s)
- Julia Pedroni
- Laboratory of Asymmetric Catalysis and Synthesis, EPFL SB ISIC LCSA, BCH 4305, 1015 Lausanne (Switzerland) http://isic.epfl.ch/lcsa
| | - Nicolai Cramer
- Laboratory of Asymmetric Catalysis and Synthesis, EPFL SB ISIC LCSA, BCH 4305, 1015 Lausanne (Switzerland) http://isic.epfl.ch/lcsa.
| |
Collapse
|
23
|
Pedroni J, Cramer N. Chiral γ-Lactams by Enantioselective Palladium(0)-Catalyzed Cyclopropane Functionalizations. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201505916] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
24
|
Beggs KM, Maiuri AR, Fullerton AM, Poulsen KL, Breier AB, Ganey PE, Roth RA. Trovafloxacin-induced replication stress sensitizes HepG2 cells to tumor necrosis factor-alpha-induced cytotoxicity mediated by extracellular signal-regulated kinase and ataxia telangiectasia and Rad3-related. Toxicology 2015; 331:35-46. [PMID: 25748550 DOI: 10.1016/j.tox.2015.03.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 02/11/2015] [Accepted: 03/04/2015] [Indexed: 01/23/2023]
Abstract
Use of the fluoroquinolone antibiotic trovafloxacin (TVX) was restricted due to idiosyncratic, drug-induced liver injury (IDILI). Previous studies demonstrated that tumor necrosis factor-alpha (TNF) and TVX interact to cause death of hepatocytes in vitro that was associated with prolonged activation of c-Jun N-terminal kinase (JNK), activation of caspases 9 and 3, and DNA damage. The purpose of this study was to explore further the mechanism by which TVX interacts with TNF to cause cytotoxicity. Treatment with TVX caused cell cycle arrest, enhanced expression of p21 and impaired proliferation, but cell death only occurred after cotreatment with TVX and TNF. Cell death involved activation of extracellular signal-related kinase (ERK), which in turn activated caspase 3 and ataxia telangiectasia and Rad3-related (ATR), both of which contributed to cytotoxicity. Cotreatment of HepG2 cells with TVX and TNF caused double-strand breaks in DNA, and ERK contributed to this effect. Inhibition of caspase activity abolished the DNA strand breaks. The data suggest a complex interaction of TVX and TNF in which TVX causes replication stress, and the downstream effects are exacerbated by TNF, leading to hepatocellular death. These results raise the possibility that IDILI from TVX results from MAPK and ATR activation in hepatocytes initiated by interaction of cytokine signaling with drug-induced replication stress.
Collapse
Affiliation(s)
- Kevin M Beggs
- Michigan State University, Department of Pharmacology & Toxicology, Center for Integrative Toxicology, 1129 Farm Lane, East Lansing, MI 48824, United States
| | - Ashley R Maiuri
- Michigan State University, Department of Pharmacology & Toxicology, Center for Integrative Toxicology, 1129 Farm Lane, East Lansing, MI 48824, United States
| | - Aaron M Fullerton
- Michigan State University, Department of Pharmacology & Toxicology, Center for Integrative Toxicology, 1129 Farm Lane, East Lansing, MI 48824, United States
| | - Kyle L Poulsen
- Michigan State University, Department of Pharmacology & Toxicology, Center for Integrative Toxicology, 1129 Farm Lane, East Lansing, MI 48824, United States
| | - Anna B Breier
- Michigan State University, Department of Pharmacology & Toxicology, Center for Integrative Toxicology, 1129 Farm Lane, East Lansing, MI 48824, United States
| | - Patricia E Ganey
- Michigan State University, Department of Pharmacology & Toxicology, Center for Integrative Toxicology, 1129 Farm Lane, East Lansing, MI 48824, United States
| | - Robert A Roth
- Michigan State University, Department of Pharmacology & Toxicology, Center for Integrative Toxicology, 1129 Farm Lane, East Lansing, MI 48824, United States.
| |
Collapse
|
25
|
Chanthamath S, Nguyen DT, Shibatomi K, Iwasa S. Highly Enantioselective Synthesis of Cyclopropylamine Derivatives via Ru(II)-Pheox-Catalyzed Direct Asymmetric Cyclopropanation of Vinylcarbamates. Org Lett 2013; 15:772-5. [DOI: 10.1021/ol303404c] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Soda Chanthamath
- Department of Environmental and Life Sciences, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi 441-8580, Japan
| | - Dao Thi Nguyen
- Department of Environmental and Life Sciences, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi 441-8580, Japan
| | - Kazutaka Shibatomi
- Department of Environmental and Life Sciences, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi 441-8580, Japan
| | - Seiji Iwasa
- Department of Environmental and Life Sciences, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi 441-8580, Japan
| |
Collapse
|
26
|
de Carné-Carnavalet B, Archambeau A, Meyer C, Cossy J, Folléas B, Brayer JL, Demoute JP. Efficient Synthesis of Substituted 3-Azabicyclo[3.1.0]hexan-2-ones from 2-Iodocyclopropanecarboxamides Using a Copper-Free Sonogashira Coupling. Chemistry 2012. [DOI: 10.1002/chem.201203153] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
27
|
Zapol'skii VA, Namyslo JC, de Meijere A, Kaufmann DE. Chemistry of polyhalogenated nitrobutadienes, 10: Synthesis of highly functionalized heterocycles with a rigid 6-amino-3-azabicyclo[3.1.0]hexane moiety. Beilstein J Org Chem 2012; 8:621-8. [PMID: 22563360 PMCID: PMC3343288 DOI: 10.3762/bjoc.8.69] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 03/23/2012] [Indexed: 12/02/2022] Open
Abstract
The nitropolychlorobutadienes 3, 4 are valuable building blocks for various amination and successive heterocyclization products. Nucleophilic substitution reactions of the partially protected, bioactive amines 1, 2 with either vinyl, imidoyl or carbonyl chlorides result in the formation of the enamines 11, 12, 13, 16, 25, the amidine 6, and the amides 20, 21, respectively. In the following, cyclization to the highly functionalized pyrazoles 27, 28, pyrimidine 26 and pyridopyrimidine 24 succeeded. Deprotection of 21, 12 and 28 proved to be only partially feasible.
Collapse
Affiliation(s)
- Viktor A Zapol'skii
- Institute of Organic Chemistry, Clausthal University of Technology, Leibnizstr. 6, 38678 Clausthal-Zellerfeld, Germany
| | | | | | | |
Collapse
|
28
|
Dacenko OP, Manoylenko OV, Grygorenko OO, Mykhailiuk PK, Volochnyuk DM, Shishkin OV, Tolmachev AA. Improved Synthesis of Monoprotected 5- and 6-Amino-2-azanorbornanes. SYNTHETIC COMMUN 2011. [DOI: 10.1080/00397911003707196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
| | | | - Oleksandr O. Grygorenko
- a Enamine Ltd. , Kyiv , Ukraine
- b Department of Chemistry , Kyiv National Taras Shevchenko University , Kyiv , Ukraine
| | - Pavel K. Mykhailiuk
- a Enamine Ltd. , Kyiv , Ukraine
- b Department of Chemistry , Kyiv National Taras Shevchenko University , Kyiv , Ukraine
| | | | - Oleg V. Shishkin
- c STC Institute for Single Crystals, National Academy of Science of Ukraine , Kharkiv , Ukraine
| | - Andrey A. Tolmachev
- a Enamine Ltd. , Kyiv , Ukraine
- b Department of Chemistry , Kyiv National Taras Shevchenko University , Kyiv , Ukraine
| |
Collapse
|
29
|
Barbour A, Scaglione F, Derendorf H. Class-dependent relevance of tissue distribution in the interpretation of anti-infective pharmacokinetic/pharmacodynamic indices. Int J Antimicrob Agents 2010; 35:431-8. [PMID: 20219329 DOI: 10.1016/j.ijantimicag.2010.01.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2009] [Revised: 01/19/2010] [Accepted: 01/21/2010] [Indexed: 10/19/2022]
Abstract
The pharmacokinetic/pharmacodynamic (PK/PD) indices useful for predicting antimicrobial clinical efficacy are well established. The most common indices include the time free drug concentration in plasma is above the minimum inhibitory concentration (MIC) (fT(>MIC)) expressed as a percent of the dosing interval, the ratio of maximum concentration to MIC (C(max)/MIC), and the ratio of the area under the 24-h concentration-time curve to MIC (AUC(0-24)/MIC). A single PK/PD index may correlate well with an entire antimicrobial class. For example, the beta-lactams correlate well with the fT(>MIC). However, other classes may be more complex and a single index cannot be generalised to the class, e.g. the macrolides. The rationale behind which PK/PD index best correlates with efficacy depends on several factors, including the mechanism of action, the microbial kill kinetics, the degree of protein binding and the degree of tissue distribution. Studies have traditionally emphasised the first two factors, whilst the significance of protein binding and tissue distribution is increasingly appreciated. In fact, the latter two factors may partially elucidate why the magnitude of reported target indices are not always as expected. For example, tigecycline and telithromycin are clinically efficacious with average serum concentrations below their MICs over a 24-h period. Therefore, to understand more fully the PK/PD relationship of antibiotics and to better predict the clinical efficacy of antibiotic dosing regimens, assessment of free drug concentrations at the site of action is warranted.
Collapse
|
30
|
Topoisomerase II inhibition involves characteristic chromosomal expression patterns. BMC Genomics 2008; 9:324. [PMID: 18611269 PMCID: PMC2488358 DOI: 10.1186/1471-2164-9-324] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2007] [Accepted: 07/08/2008] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND The phenomenon of co-localization of transcriptionally upregulated genes showing similar expression levels is known across all eukaryotic genomes. We recently mapped the Aroclor 1254-regulated transcriptome back onto the genome and provided evidence for the statistically significant co-localization of regulated genes. They did, however, not always show similar expression levels, and many of the regulated genes were, in fact, repressed. RESULTS In this study, we were able to reproduce this observation with microarray data stemming from 1) human hepatocytes treated with the gyrase and potential topoisomerase II inhibitor trovafloxacin, 2) human hepatocytes treated with the topoisomerase II inhibitor doxorubicin and 3) mouse lymphoma cells treated with the topoisomerase II inhibitor etoposide. We found statistically significant co-localization of regulated gene pairs--induced and repressed--within the window size of 0-100 kbp. Notably, by using microarray data stemming from lung tissue of a mouse transgenic line overexpressing the transcription factor c-myc, which served as a negative control, we found regulated genes to be located with regard to each other nearly in the same way as genes distributed randomly all over the genome (0-100 kbp). CONCLUSION We suggest topoisomerase II inhibition by Aroclor 1254, trovafloxacin, doxorubicin, and etoposide to be responsible for significant co-localization of regulated genes through the inability of the stabilized enzyme complexes to religate DNA. Within the permanently opened chromatin domains, neighbored genes might be allowed to be regulated. Overexpression of c-myc, however, does not inhibit topoisomerase II activity. Consequently, the enzyme is able to perform its normal function of transiently breaking and rejoining the DNA double strand. As a result, exclusively target genes are regulated.
Collapse
|
31
|
Volturo GA, Low DE, Aghababian R. Managing acute lower respiratory tract infections in an era of antibacterial resistance. Am J Emerg Med 2006; 24:329-42. [PMID: 16635707 DOI: 10.1016/j.ajem.2005.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Accepted: 10/04/2005] [Indexed: 11/22/2022] Open
Abstract
Respiratory tract infections account for more than 116 million office visits and an estimated 3 million visits to hospital EDs annually. Patients presenting at EDs with symptoms suggestive of lower respiratory tract infections of suspected bacterial etiology are often severely ill, thus requiring a rapid presumptive diagnosis and empiric antimicrobial treatment. Traditionally, clinicians have relied on beta-lactam or macrolide antibiotics to manage community-acquired lower respiratory tract infections. However, the emerging resistance of Streptococcus pneumoniae to beta-lactams and/or macrolides may affect the clinical efficacy of these agents. Inappropriate use of antibiotics and use of agents with an overly broad spectrum of antimicrobial activity have contributed to the emergence of antibiotic resistance. When treating respiratory infections, clinicians need to prescribe antimicrobial agents only for those individuals with infections of suspected bacterial etiology; to select agents with a targeted spectrum of activity that ensures coverage against typical S pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis strains, including antibiotic-resistant strains and atypical pathogens; and to consider agents with specific chemical properties that limit the development of antimicrobial resistance and that achieve concentrations at sites of infection that exceed those required for bactericidal activity. Newer classes of antimicrobial agents, such as the oxazolidinones and ketolides, will likely play a significant role in this era of antimicrobial resistance.
Collapse
Affiliation(s)
- Gregory A Volturo
- Department of Emergency Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | | | | |
Collapse
|
32
|
Cottagnoud P, Johnson M, Cottagnoud M, Piddock L. Preincubation of pneumococci with beta-lactams alone or combined with levofloxacin prevents quinolone-induced resistance without increasing intracellular levels of levofloxacin. Antimicrob Agents Chemother 2005; 49:3517-9. [PMID: 16048972 PMCID: PMC1196276 DOI: 10.1128/aac.49.8.3517-3519.2005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Preincubation of pneumococci with sub-MIC concentrations of ceftriaxone (1/16x MIC), cefotaxime (1/8x MIC), and meropenem (1/4x MIC) alone or combined with levofloxacin (1/8x MIC) over 6 h prevents the emergence of levofloxacin-resistant mutants after 96 h of incubation but does not affect the intracellular accumulation of levofloxacin in two penicillin-resistant pneumococcal strains, suggesting a link between the mechanism of action of beta-lactams and the emergence of quinolone-induced resistance in pneumococci.
Collapse
Affiliation(s)
- Philippe Cottagnoud
- Department of Internal Medicine, Inselspital, Freiburgstrasse, 3010 Bern, Switzerland.
| | | | | | | |
Collapse
|
33
|
Abstract
Gemifloxacin is a dual targeted fluoroquinolone with potent in vitro activity against Gram-positive, -negative and atypical human pathogens--pathogens considered to be important causes of community-acquired respiratory tract infections. Gemifloxacin demonstrates impressive minimal inhibitory concentrations (MIC 90 ) values against clinical isolates of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Chlamydia pneumoniae and Legionella spp., with MIC 90 values reported to be 0.016-0.06, < 0.0008-0.06, 0.008-0.3, 0.25, 0.125 and 0.016-0.07 microg/ml, respectively. Gemifloxacin is also active in vitro against a broad range of Gram-negative bacilli with MIC 90 values against the Enterobacteriaceae in the range of 0.016 to > 16 microg/ml ( Escherichia coli and Providencia stuartii, respectively), with the majority of the genus having MIC 90 drug concentrations < 0.5 microg/ml. The in vitro activity of gemifloxacin against anaerobic organisms is variable. The MIC values for gemifloxacin are not affected by beta-lactamase production nor by penicillin or macrolide resistance in S. pneumoniae. Gemifloxacin is approved by the FDA to be clinically efficacious against multi-drug resistant S. pneumoniae. The pharmacokinetics of gemifloxacin are such that the drug can be administered orally once-daily to yield or achieve sustainable drug concentrations exceeding the MIC values of clinically important organisms. Gemifloxacin has been shown to target both DNA gyrase (preferred target) and topoisomerase IV (secondary target) - enzymes critical for DNA replication and organism survival - against clinical isolates of S. pneumoniae. This dual targeting activity is thought to be important for reducing the likelihood for selecting for quinolone resistance. Gemifloxacin has been investigated and approved for therapy in patients with community-acquired pneumonia (CAP) and acute exacerbations of chronic bronchitis. In one study, more patients receiving gemifloxacin compared to clarithromycin remained free of exacerbations for longer periods of time (p < 0.016) and gemifloxacin had a shorter time to eradication of H. influenzae than did clarithromycin (p < 0.02). From efficacy studies, gemifloxacin was found to have an adverse profile that was comparable with other compounds. The most frequent side effects were diarrhoea, abdominal pain and headache. Gemifloxacin is a welcomed addition to currently available agents for the treatment of community-acquired lower respiratory tract infections. Other potential indications appear to be within the spectrum of this compound.
Collapse
Affiliation(s)
- Joseph M Blondeau
- Department of Microbiology, Royal University Hospital, Saskatoon, Saschatchewan, Canada.
| | | |
Collapse
|
34
|
Abstract
This article discusses the newer fluoroquinolones in detail with respect to their pharmacokinetics, pharmacodynamics, safety, and spectrum of in vitro activity. The newer agents are compared and contrasted with the older ones, particularly ciprofloxacin. Efficacy of the newer fluoroquinolones when compared with antimicrobial agents in other classes is also presented in detail. Appropriate use of the newer fluoroquinolones is addressed, including their ever expanding role in the treatment of both upper and lower respiratory tract infections and skin and soft tissue infection. Available data on the use of the newer fluoroquinolones in the management of genitourinary tract infections, gastrointestinal infections, and osteomyelitis are also discussed.
Collapse
Affiliation(s)
- Judith A O'Donnell
- Division of Infectious Diseases, Drexel University, College of Medicine, Medical College of PA Hospital, 3300 Henry Avenue, Philadelphia, PA 19129, USA.
| | | |
Collapse
|
35
|
|
36
|
Cottagnoud P, Cottagnoud M, Acosta F, Flatz L, Kühn F, Stucki A, Entenza J. Meropenem prevents levofloxacin-induced resistance in penicillin-resistant pneumococci and acts synergistically with levofloxacin in experimental meningitis. Eur J Clin Microbiol Infect Dis 2003; 22:656-62. [PMID: 14557920 DOI: 10.1007/s10096-003-1016-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The aim of the present study was to investigate the potential synergy between meropenem and levofloxacin in vitro and in experimental meningitis and to determine the effect of meropenem on levofloxacin-induced resistance in vitro. Meropenem increased the efficacy of levofloxacin against the penicillin-resistant pneumococcal strain KR4 in time-killing assays in vitro and acted synergistically against a second penicillin-resistant strain WB4. In the checkerboard, only an additive effect (FIC indices: 1.0) was observed for both strains. In cycling experiments in vitro, levofloxacin alone led to a 64-fold increase in the MIC for both strains after 12 cycles. Addition of meropenem in sub-MIC concentrations (0.25 x MIC) completely inhibited the selection of levofloxacin-resistant mutants in WB4 after 12 cycles. In KR4, the addition of meropenem led to just a twofold increase in the MIC for levofloxacin after 12 cycles. Mutations detected in the genes encoding for topoisomerase IV (parC) and gyrase (gyrA) confirmed the levofloxacin-induced resistance in both strains. Addition of meropenem was able to completely suppress levofloxacin-induced mutations in WB4 and led to only one mutation in parE in KR4. In experimental meningitis, meropenem, given in two doses (2 x 125 mg/kg), produced a good bactericidal activity (-0.45 Deltalog10 cfu/ml.h) comparable to one dose (1 x 10 mg/kg) of levofloxacin (-0.44 Deltalog10 cfu/ml.h) against the penicillin-resistant strain WB4. Meropenem combined with levofloxacin acted synergistically (-0.93 Deltalog10 cfu/ml.h), sterilizing the CSF of all rabbits.
Collapse
Affiliation(s)
- P Cottagnoud
- Department of Internal Medicine, Inselspital, Freiburgstrasse, 3010 Bern, Switzerland.
| | | | | | | | | | | | | |
Collapse
|
37
|
Kühn F, Cottagnoud M, Acosta F, Flatz L, Entenza J, Cottagnoud P. Cefotaxime acts synergistically with levofloxacin in experimental meningitis due to penicillin-resistant pneumococci and prevents selection of levofloxacin-resistant mutants in vitro. Antimicrob Agents Chemother 2003; 47:2487-91. [PMID: 12878509 PMCID: PMC166100 DOI: 10.1128/aac.47.8.2487-2491.2003] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cefotaxime, given in two doses (each 100 mg/kg of body weight), produced a good bactericidal activity (-0.47 Deltalog(10) CFU/ml. h) which was comparable to that of levofloxacin (-0.49 Deltalog(10) CFU/ml. h) against a penicillin-resistant pneumococcal strain WB4 in experimental meningitis. Cefotaxime combined with levofloxacin acted synergistically (-1.04 Deltalog(10) CFU/ml. h). Synergy between cefotaxime and levofloxacin was also demonstrated in vitro in time killing assays and with the checkerboard method for two penicillin-resistant strains (WB4 and KR4). Using in vitro cycling experiments, the addition of cefotaxime in sub-MIC concentrations (one-eighth of the MIC) drastically reduced levofloxacin-induced resistance in the same two strains (64-fold increase of the MIC of levofloxacin after 12 cycles versus 2-fold increase of the MIC of levofloxacin combined with cefotaxime). Mutations detected in the genes encoding topoisomerase IV (parC and parE) and gyrase (gyrA and gyrB) confirmed the levofloxacin-induced resistance in both strains. Addition of cefotaxime in low doses was able to suppress levofloxacin-induced resistance.
Collapse
Affiliation(s)
- F Kühn
- Department of Internal Medicine, Spital Bern-Ziegler, Inselspital, Bern, Switzerland
| | | | | | | | | | | |
Collapse
|
38
|
Abstract
The quinolone antibiotics have been a major advance for the treatment of various types of infections. These agents have generally good safety profiles, broad-spectrum activity, and favorable pharmacokinetics. In addition, several of these antibiotics are available in both intravenous and oral formulations, which allows for sequential therapy resulting in potential cost savings. However, patients can develop serious central nervous system side effects (seizures) and phototoxicity. In addition, the bioavailability of agents in this class can be reduced by coadministration with cations, such as magnesium, aluminum, calcium, and iron, which may make bioavailability unpredictable in patients. Although older quinolones such as ciprofloxacin were effective as prophylactic agents for biliary procedures and colorectal surgery and for the treatment of intra-abdominal infections, the use of these older quinolones was limited by the development of resistant organisms. In addition, because these agents had poor activity against anaerobes such as Bacteroides fragilis, the agents had to be combined with an antianaerobic agent, such as metronidazole, when anaerobic coverage was required. Recently, a new quinolone, trovafloxacin, has become available. Trovafloxacin has demonstrated increased activity against anaerobes in animal and human studies. However, the clinical profile of trovafloxacin for abdominal infections has not been fully demonstrated, and there is some concern that its activity against aerobic gram-negative bacilli, especially Pseudomonas aeruginosa, may not equal that of ciprofloxacin. Moreover, the safety profile of trovafloxacin is disadvantageous owing to reports of severe hepatic toxicity.
Collapse
Affiliation(s)
- R L Nichols
- Department of Surgery, Tulane University School of Medicine, New Orleans, LA 70112-2699, USA.
| |
Collapse
|
39
|
de la Campa AG, Ferrandiz MJ, Tubau F, Pallarés R, Manresa F, Liñares J. Genetic characterization of fluoroquinolone-resistant Streptococcus pneumoniae strains isolated during ciprofloxacin therapy from a patient with bronchiectasis. Antimicrob Agents Chemother 2003; 47:1419-22. [PMID: 12654682 PMCID: PMC152524 DOI: 10.1128/aac.47.4.1419-1422.2003] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Five Spain(9V-3) Streptococcus pneumoniae strains were isolated from a patient with bronchiectasis who had received long-term ciprofloxacin therapy. One ciprofloxacin-susceptible strain was isolated before treatment, and four ciprofloxacin-resistant strains were isolated during treatment. The resistant strains were derived from the susceptible strain either by a parC mutation (low-level resistance) or by parC and gyrA mutations (high-level resistance). This study shows that ciprofloxacin therapy in a patient colonized by susceptible S. pneumoniae may select fluoroquinolone-resistant mutants.
Collapse
Affiliation(s)
- Adela G de la Campa
- Unidad de Genética Bacteriana (Consejo Superior de Investigaciones Científicas), Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain.
| | | | | | | | | | | |
Collapse
|
40
|
Johnsen PJ, Simonsen GS, Olsvik O, Midtvedt T, Sundsfjord A. Stability, persistence, and evolution of plasmid-encoded VanA glycopeptide resistance in enterococci in the absence of antibiotic selection in vitro and in gnotobiotic mice. Microb Drug Resist 2003; 8:161-70. [PMID: 12363004 DOI: 10.1089/107662902760326869] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Long-term persistence of VanA glycopeptide-resistant enterococci (GRE) has been observed in the absence of antibiotic selection. In the present study, we examined fitness parameters of a glycopeptide-susceptible Enterococcus faecium parent strain and its plasmid-mediated, VanA-resistant derivative before and after 1,000 generations in serial transfer broth cultures with or without antibiotic selection. With the exception of the vanA-containing plasmid, the strains were otherwise isogenic. The stability of the plasmid-encoded vanA resistance determinant was also investigated in vitro and in gnotobiotic mice. Competition experiments revealed that GRE with newly acquired VanA resistance had a 4% reduction in fitness relative to their susceptible parental counterpart. The relative difference in competitive fitness between resistant and susceptible strains was not significantly changed after 1,000 generations. Environmental adaptation was observed in all strains and exceeded the biological cost of resistance. Thus, the evolved VanA-resistant E. faecium populations out-numbered their unevolved ancestral susceptible E. faecium strain in mixed cultures, but remained less competitive than the evolved parent. The glycopeptide resistance determinant was similarly stably maintained during long-term colonization in gnotobiotic mice without antibiotic selection. In vivo vanA plasmid transfer was observed. The results suggest that environmental adaptation, in vivo gene transfer, and plasmid maintenance system(s) favor long-term VanA GRE persistence without antibiotic selection and compensate for the biological costs of possessing the resistance genes.
Collapse
Affiliation(s)
- Pål J Johnsen
- Department of Microbiology and Virology, University and University Hospital of Tromsø, Norway.
| | | | | | | | | |
Collapse
|
41
|
Browne FA, Clark C, Bozdogan B, Dewasse BE, Jacobs MR, Appelbaum PC. Single and multi-step resistance selection study in Streptococcus pneumoniae comparing ceftriaxone with levofloxacin, gatifloxacin and moxifloxacin. Int J Antimicrob Agents 2003; 20:93-9. [PMID: 12297357 DOI: 10.1016/s0924-8579(02)00120-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Attempts were made to select resistant pneumococcal mutants by sequential subculturing of 12 clinically isolated pneumococci, [four were penicillin sensitive (MIC) 0.03-0.06 mg/l, four penicillin intermediate (MIC 0.25-0.5 mg/l) and four penicillin resistant (MIC 2-4 mg/l)] in sub-inhibitory concentrations of ceftriaxone, levofloxacin, gatifloxacin and moxifloxacin. Subculturing in gatifloxacin, levofloxacin, moxifloxacin and ceftriaxone selected 12 mutants (12/12), 10 mutants (10/12), 10 mutants (10/12) and three mutants (3/12), respectively. DNA sequencing of the quinolone-resistant mutants showed that most strains had mutations in GyrA at E85 or S81. This in vitro mutation study demonstrates a clear distinction between the low frequency of development of resistance with ceftriaxone exposure as opposed to the high frequency with quinolone exposure.
Collapse
Affiliation(s)
- Frederick A Browne
- Department of Medicine, Hershey Medical Center, 500 University Drive, PA 17033, USA
| | | | | | | | | | | |
Collapse
|
42
|
Zhanel GG, Ennis K, Vercaigne L, Walkty A, Gin AS, Embil J, Smith H, Hoban DJ. A critical review of the fluoroquinolones: focus on respiratory infections. Drugs 2002; 62:13-59. [PMID: 11790155 DOI: 10.2165/00003495-200262010-00002] [Citation(s) in RCA: 269] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The new fluoroquinolones (clinafloxacin, gatifloxacin, gemifloxacin, grepafloxacin, levofloxacin, moxifloxacin, sitafloxacin, sparfloxacin and trovafloxacin) offer excellent activity against Gram-negative bacilli and improved Gram-positive activity (e.g. against Streptococcus pneumoniae and Staphylococcus aureus) over ciprofloxacin. Ciprofloxacin still maintains the best in vitro activity against Pseudomonas aeruginosa. Clinafloxacin, gatifloxacin, moxifloxacin, sitafloxacin, sparfloxacin and trovafloxacin display improved activity against anaerobes (e.g. Bacteroides fragilis) versus ciprofloxacin. All of the new fluoroquinolones display excellent bioavailability and have longer serum half-lives than ciprofloxacin allowing for once daily dose administration. Clinical trials comparing the new fluoroquinolones to each other or to standard therapy have demonstrated good efficacy in a variety of community-acquired respiratory infections (e.g. pneumonia, acute exacerbations of chronic bronchitis and acute sinusitis). Limited data suggest that the new fluoroquinolones as a class may lead to better outcomes in community-acquired pneumonia and acute exacerbations of chronic bronchitis versus comparators. Several of these agents have either been withdrawn from the market, had their use severely restricted because of adverse effects (clinafloxacin because of phototoxicity and hypoglycaemia; grepafloxacin because of prolongation of the QTc and resultant torsades de pointes; sparfloxacin because of phototoxicity; and trovafloxacin because of hepatotoxicity), or were discontinued during developmental phases. The remaining fluoroquinolones such as gatifloxacin, gemifloxacin, levofloxacin and moxifloxacin have adverse effect profiles similar to ciprofloxacin. Extensive post-marketing safety surveillance data (as are available with ciprofloxacin and levofloxacin) are required for all new fluoroquinolones before safety can be definitively established. Drug interactions are limited; however, all fluoroquinolones interact with metal ion containing drugs (eg. antacids). The new fluoroquinolones (gatifloxacin, gemifloxacin, levofloxacin and moxifloxacin) offer several advantages over ciprofloxacin and are emerging as important therapeutic agents in the treatment of community-acquired respiratory infections. Their broad spectrum of activity which includes respiratory pathogens such as penicillin and macrolide resistant S. pneumoniae, favourable pharmacokinetic parameters, good bacteriological and clinical efficacy will lead to growing use of these agents in the treatment of community-acquired pneumonia, acute exacerbations of chronic bronchitis and acute sinusitis. These agents may result in cost savings especially in situations where, because of their potent broad-spectrum activity and excellent bioavailability, they may be used orally in place of intravenous antibacterials. Prudent use of the new fluoroquinolones will be required to minimise the development of resistance to these agents.
Collapse
Affiliation(s)
- George G Zhanel
- Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.
| | | | | | | | | | | | | | | |
Collapse
|
43
|
Morris JE, Pan XS, Fisher LM. Grepafloxacin, a dimethyl derivative of ciprofloxacin, acts preferentially through gyrase in Streptococcus pneumoniae: role of the C-5 group in target specificity. Antimicrob Agents Chemother 2002; 46:582-5. [PMID: 11796384 PMCID: PMC127062 DOI: 10.1128/aac.46.2.582-585.2002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Grepafloxacin, a 5-methyl-7-piperazinyl-3"-methyl analogue of ciprofloxacin, was used to obtain stepwise-selected mutants of Streptococcus pneumoniae 7785. Analysis of the quinolone resistance-determining regions of the gyrA, gyrB, parC, and parE genes in these mutants revealed that gyrA mutations preceded those in parC. Given that ciprofloxacin (5-H,7-piperazinyl) and AM-1121 (5-H,7-piperazinyl-3"-methyl) both act through topoisomerase IV, we conclude that the 5-methyl group of grepafloxacin favors gyrase in S. pneumoniae.
Collapse
Affiliation(s)
- Julia E Morris
- Molecular Genetics Group, Department of Biochemistry and Immunology, St. George's Hospital Medical School, University of London, London SW17 0RE, United Kingdom
| | | | | |
Collapse
|
44
|
Yague G, Morris JE, Pan XS, Gould KA, Fisher LM. Cleavable-complex formation by wild-type and quinolone-resistant Streptococcus pneumoniae type II topoisomerases mediated by gemifloxacin and other fluoroquinolones. Antimicrob Agents Chemother 2002; 46:413-9. [PMID: 11796351 PMCID: PMC127068 DOI: 10.1128/aac.46.2.413-419.2002] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gemifloxacin is a recently developed fluoroquinolone with potent activity against Streptococcus pneumoniae. We show that the drug is more active than moxifloxacin, gatifloxacin, levofloxacin, and ciprofloxacin against S. pneumoniae strain 7785 (MICs, 0.03 to 0.06 microg/ml versus 0.25, 0.25, 1, and 1 to 2 microg/ml, respectively) and against isogenic quinolone-resistant gyrA-parC mutants (MICs, 0.5 to 1 microg/ml versus 2 to 4, 2 to 4, 16 to 32, and 64 microg/ml, respectively). Gemifloxacin was also the most potent agent against purified S. pneumoniae DNA gyrase and topoisomerase IV in both catalytic inhibition and DNA cleavage assays. The drug concentrations that inhibited DNA supercoiling or DNA decatenation by 50% (IC(50)s) were 5 to 10 and 2.5 to 5.0 microM, respectively. Ciprofloxacin and levofloxacin were some four- to eightfold less active against either enzyme; moxifloxacin and gatifloxacin showed intermediate activities. In assays of drug-mediated DNA cleavage by gyrase and topoisomerase IV, the same order of potency was seen: gemifloxacin > moxifloxacin > gatifloxacin > levofloxacin approximately ciprofloxacin. For gemifloxacin, the drug concentrations that caused 25% linearization of the input DNA by gyrase and topoisomerase IV were 2.5 and 0.1 to 0.3 microM, respectively; these values were 4-fold and 8- to 25-fold lower than those for moxifloxacin, respectively. Each drug induced DNA cleavage by gyrase at the same spectrum of sites but with different patterns of intensity. Finally, for enzymes reconstituted with quinolone-resistant GyrA S81F or ParC S79F subunits, although cleavable-complex formation was reduced by at least 8- to 16-fold for all the quinolones tested, gemifloxacin was the most effective; e.g., it was 4- to 16-fold more active than the other drugs against toposiomerase IV with the ParC S79F mutation. It appears that the greater potency of gemifloxacin against both wild-type and quinolone-resistant S. pneumoniae strains arises from enhanced stabilization of gyrase and topoisomerase IV complexes on DNA.
Collapse
Affiliation(s)
- Genoveva Yague
- Molecular Genetics Group, Department of Biochemistry and Immunology, St. George's Hospital Medical School, University of London, London SW17 0RE, United Kingdom
| | | | | | | | | |
Collapse
|
45
|
Pan XS, Yague G, Fisher LM. Quinolone resistance mutations in Streptococcus pneumoniae GyrA and ParC proteins: mechanistic insights into quinolone action from enzymatic analysis, intracellular levels, and phenotypes of wild-type and mutant proteins. Antimicrob Agents Chemother 2001; 45:3140-7. [PMID: 11600369 PMCID: PMC90795 DOI: 10.1128/aac.45.11.3140-3147.2001] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Mutations in DNA gyrase and/or topoisomerase IV genes are frequently encountered in quinolone-resistant mutants of Streptococcus pneumoniae. To investigate the mechanism of their effects at the molecular and cellular levels, we have used an Escherichia coli system to overexpress S. pneumoniae gyrase gyrA and topoisomerase IV parC genes encoding respective Ser81Phe and Ser79Phe mutations, two changes widely associated with quinolone resistance. Nickel chelate chromatography yielded highly purified mutant His-tagged proteins that, in the presence of the corresponding GyrB and ParE subunits, reconstituted gyrase and topoisomerase IV complexes with wild-type specific activities. In enzyme inhibition or DNA cleavage assays, these mutant enzyme complexes were at least 8- to 16-fold less responsive to both sparfloxacin and ciprofloxacin. The ciprofloxacin-resistant (Cip(r)) phenotype was silent in a sparfloxacin-resistant (Spx(r)) S. pneumoniae gyrA (Ser81Phe) strain expressing a demonstrably wild-type topoisomerase IV, whereas Spx(r) was silent in a Cip(r) parC (Ser79Phe) strain. These epistatic effects provide strong support for a model in which quinolones kill S. pneumoniae by acting not as enzyme inhibitors but as cellular poisons, with sparfloxacin killing preferentially through gyrase and ciprofloxacin through topoisomerase IV. By immunoblotting using subunit-specific antisera, intracellular GyrA/GyrB levels were a modest threefold higher than those of ParC/ParE, most likely insufficient to allow selective drug action by counterbalancing the 20- to 40-fold preference for cleavable-complex formation through topoisomerase IV observed in vitro. To reconcile these results, we suggest that drug-dependent differences in the efficiency by which ternary complexes are formed, processed, or repaired in S. pneumoniae may be key factors determining the killing pathway.
Collapse
Affiliation(s)
- X S Pan
- Molecular Genetics Group, Department of Biochemistry and Immunology, St. George's Hospital Medical School, University of London, London SW17 0RE, United Kingdom
| | | | | |
Collapse
|
46
|
Abstract
A topoisomerase was identified as the bacterial target site for quinolone action in the late 1970s. Since that time, further study identified two bacterial topoisomerases, DNA gyrase and topoisomerase IV, as sites of antibacterial activity DNA gyrase appears to be the primary quinolone target for gram-negative bacteria. Topoisomerase IV appears to be the preferential target in gram-positive organisms, but this varies with the drug. Three mechanisms of resistance against quinolones are mutations of topoisomerases, decreased membrane permeability, and active drug efflux. Although these mechanisms occur singly, several resistance factors are often required to produce clinically applicable increases in minimum inhibitory concentrations. Appropriate drug selection and dosage and prudent human and veterinary interventions are important factors in controlling the emergence of resistance.
Collapse
Affiliation(s)
- D T Bearden
- College of Pharmacy, Oregon State University, Portland, USA
| | | |
Collapse
|
47
|
Doern GV. Antimicrobial use and the emergence of antimicrobial resistance with Streptococcus pneumoniae in the United States. Clin Infect Dis 2001; 33 Suppl 3:S187-92. [PMID: 11524718 DOI: 10.1086/321847] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
The rapid emergence of resistance to antimicrobial agents by Streptococcus pneumoniae in the United States has been influenced by various factors, including the clonal nature of most resistant strains and the fact that organisms with a multiresistant phenotype have become stably endemic. The ease with which transmission occurs and the fact that humans, especially children, are often colonized asymptomatically in the upper respiratory tract have contributed to the problem. Clearly, the most important factor in the emergence of antimicrobial resistance with S. pneumoniae, however, is the selective pressure of antimicrobial agents. Potency, defined as a product of both antibacterial effect and drug delivery, is a key factor. Generally speaking, the more potent an antimicrobial agent, the less likely it is to select for resistance. This is germane to comparisons of oral agents within specific antimicrobial classes (e.g., beta-lactams, macrolides, and fluoroquinolones). Within each class, potencies differ. In view of the existence of stably endemic multidrug-resistant S. pneumoniae, given comparable cost, side-effect profile, palatability, convenience of dosing, and accessibility, use of the most potent agent(s) within a particular class is advocated.
Collapse
Affiliation(s)
- G V Doern
- Division of Medical Microbiology, Department of Pathology, University of Iowa College of Medicine, Iowa City, IA 52242, USA.
| |
Collapse
|
48
|
Richardson DC, Bast D, McGeer A, Low DE. Evaluation of susceptibility testing to detect fluoroquinolone resistance mechanisms in Streptococcus pneumoniae. Antimicrob Agents Chemother 2001; 45:1911-4. [PMID: 11353652 PMCID: PMC90572 DOI: 10.1128/aac.45.6.1911-1914.2001] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To determine if susceptibility testing of Streptococcus pneumoniae could detect those isolates that had one of the recognized mechanisms of fluoroquinolone resistance, 101 isolates were selected; the levofloxacin MIC for 28 of these isolates was > or =4 microg/ml. Only isolates with both parC and gyrA mutations or with no recognized resistance mechanisms were reliably identified by using these results. Isolates with only a parC mutation could not be detected reliably using any susceptibility testing method.
Collapse
Affiliation(s)
- D C Richardson
- Toronto Medical Laboratories and Mount Sinai Hospital Department of Microbiology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
| | | | | | | |
Collapse
|
49
|
Fukuda H, Kishii R, Takei M, Hosaka M. Contributions of the 8-methoxy group of gatifloxacin to resistance selectivity, target preference, and antibacterial activity against Streptococcus pneumoniae. Antimicrob Agents Chemother 2001; 45:1649-53. [PMID: 11353607 PMCID: PMC90527 DOI: 10.1128/aac.45.6.1649-1653.2001] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gatifloxacin (8-methoxy, 7-piperazinyl-3'-methyl) at the MIC selected mutant strains that possessed gyrA mutations at a low frequency (3.7 x 10(-9)) from wild-type strain Streptococcus pneumoniae IID553. AM-1147 (8-methoxy, 7-piperazinyl-3'-H) at the MIC or higher concentrations selected no mutant strains. On the other hand, the respective 8-H counterparts of these two compounds, AM-1121 (8-H, 7-piperazinyl-3'-methyl) and ciprofloxacin (8-H, 7-piperazinyl-3'-H), at one and two times the MIC selected mutant strains that possessed parC mutations at a high frequency (>2.4 x 10(-6)). The MIC of AM-1147 increased for the gyrA mutant strains but not for the parC mutant strains compared with that for the wild-type strain. These results suggest that fluoroquinolones that harbor 8-methoxy groups select mutant strains less frequently and prefer DNA gyrase, as distinct from their 8-H counterparts. The in vitro activities of gatifloxacin and AM-1147 are twofold higher against the wild-type strain, eight- and twofold higher against the first-step parC and gyrA mutant strains, respectively, and two- to eightfold higher against the second-step gyrA and parC double mutant strains than those of their 8-H counterparts. These results indicate that the 8-methoxy group contributes to enhancement of antibacterial activity against target-altered mutant strains as well as the wild-type strain. It is hypothesized that the 8-methoxy group of gatifloxacin increases the level of target inhibition, especially against DNA gyrase, so that it is nearly the same as that for topoisomerase IV inhibition in the bacterial cell, leading to potent antibacterial activity and a low level of resistance selectivity.
Collapse
Affiliation(s)
- H Fukuda
- Central Research Laboratories, Kyorin Pharmaceutical Co., Ltd., 2399-1, Mitarai, Nogi, Shimotsuga, Tochigi 329-0114, Japan.
| | | | | | | |
Collapse
|
50
|
Coyle EA, Kaatz GW, Rybak MJ. Activities of newer fluoroquinolones against ciprofloxacin-resistant Streptococcus pneumoniae. Antimicrob Agents Chemother 2001; 45:1654-9. [PMID: 11353608 PMCID: PMC90528 DOI: 10.1128/aac.45.6.1654-1659.2001] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The incidence of ciprofloxacin resistance in Streptococcus pneumoniae is low but steadily increasing, which raises concerns regarding the clinical impact of potential cross-resistance with newer fluoroquinolones. To investigate this problem, we utilized an in vitro pharmacodynamic model and compared the activities of gatifloxacin, grepafloxacin, levofloxacin, moxifloxacin, and trovafloxacin to that of ciprofloxacin against two laboratory-derived, ciprofloxacin-resistant derivatives of S. pneumoniae (strains R919 and R921). Ciprofloxacin resistance in these strains involved the activity of a multidrug efflux pump and possibly, for R919, a mutation resulting in an amino acid substitution in GyrA. Gatifloxacin, grepafloxacin, levofloxacin, moxifloxacin, and trovafloxacin achieved 99.9% killing of both R919 and R921 in < or =28 h. With respect to levofloxacin, significant regrowth of both mutants was observed at 48 h (P < 0.05). For gatifloxacin, grepafloxacin, moxifloxacin, and trovafloxacin, regrowth was minimal at 48 h, with each maintaining 99.9% killing against both mutants. No killing of either R919 or R921 was observed with exposure to ciprofloxacin. During model experiments, resistance to gatifloxacin, grepafloxacin, moxifloxacin, and trovafloxacin did not develop but the MICs of ciprofloxacin and levofloxacin increased 1 to 2 dilutions for both R919 and R921. Although specific area under the concentration-time curve from 0 to 24 h (AUC(0--24))/MIC and maximum concentration of drug in serum (C(max))/MIC ratios have not been defined for the fluoroquinolones with respect to gram-positive organisms, our study revealed that significant regrowth and/or resistance was associated with AUC(0-24)/MIC ratios of < or =31.7 and C(max)/MIC ratios of < or =3.1. It is evident that the newer fluoroquinolones tested possess improved activity against S. pneumoniae, including strains for which ciprofloxacin MICs were elevated.
Collapse
Affiliation(s)
- E A Coyle
- The Anti-Infective Research Laboratory and Department of Pharmacy Services, Detroit Receiving Hospital and University Health Center, Wayne State University, Detroit, Michigan 48201, USA
| | | | | |
Collapse
|