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Zoraghi R, Reiner NE. Protein interaction networks as starting points to identify novel antimicrobial drug targets. Curr Opin Microbiol 2013; 16:566-72. [PMID: 23938265 DOI: 10.1016/j.mib.2013.07.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 07/12/2013] [Accepted: 07/16/2013] [Indexed: 01/17/2023]
Abstract
Novel classes of antimicrobials are needed to address the challenge of multidrug-resistant bacteria. Current bacterial drug targets mainly consist of specific proteins or subsets of proteins without regard for either how these targets are integrated in cellular networks or how they may interact with host proteins. However, proteins rarely act in isolation, and the majority of biological processes are dependent on interactions with other proteins. Consequently, protein-protein interaction (PPI) networks offer a realm of unexplored potential for next-generation drug targets. In this review, we argue that the architecture of bacterial or host-pathogen protein interactomes can provide invaluable insights for the identification of novel antibacterial drug targets.
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Affiliation(s)
- Roya Zoraghi
- Division of Infectious Diseases, Department of Medicine, University of British Columbia, Vancouver, Canada
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Gobalakrishnan R, Kulandaivelu M, Bhuvaneswari R, Kandavel D, Kannan L. Screening of wild plant species for antibacterial activity and phytochemical analysis of Tragia involucrata L. J Pharm Anal 2013; 3:460-465. [PMID: 29403856 PMCID: PMC5761011 DOI: 10.1016/j.jpha.2013.07.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 07/09/2013] [Indexed: 11/16/2022] Open
Abstract
Eight wild plant species namely Tragia involucrata L., Cleistanthus collinus (Roxb.)Benth. Ex Hook.f., Sphaeranthus indicus L., Vicoa indica (L.) Dc., Allmania nodiflora (L.) R.Br. ex wight., Habenaria elliptica Wight., Eriocaulon thwaitesii Koern. and Evolvulus alsinoides L. were used for phytochemical extraction with four different solvents. Antibacterial activity of these plants was studied against Escherichia coli NCIM 2065 using Kirby Bauer agar disc diffusion assay. Effective antibacterial activity was shown by T. involucrata acetone extract (27.3 mm), compared to standard medicinal drug amoxicillin (28.3 mm). Minimum inhibitory concentration (MIC) of T. involucrata extract was 15 mg/mL and hence, it could be pursued further for obtaining phytomedicine. Biochemical constituents of T. involucrata fresh leaf were: sugars (55 mg/g), starch (0.7182 mg/g), proteins (0.0166 mg/g) and lipids (170 mg/g). Alkaloids, tannins, phenolic compounds, flavonoids and steroids were also observed qualitatively.
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Affiliation(s)
- R. Gobalakrishnan
- CAS in Marine Biology, Faculty of Marine Sciences, Annamalai University, Parangipettai, 608 502 Tamilnadu, India
- Corresponding author. Tel.: +91 4144 252099, mobile: +91 8124800850; fax: +91 4144 243999, +91 4144243555.
| | - M. Kulandaivelu
- PG and Research Department of Botany, H.H. The Rajah's College (Au), Pudukkottai, 622 001 Tamilnadu, India
| | - R. Bhuvaneswari
- PG and Research Department of Botany, H.H. The Rajah's College (Au), Pudukkottai, 622 001 Tamilnadu, India
| | - D. Kandavel
- PG and Research Department of Botany, H.H. The Rajah's College (Au), Pudukkottai, 622 001 Tamilnadu, India
| | - L. Kannan
- CAS in Marine Biology, Faculty of Marine Sciences, Annamalai University, Parangipettai, 608 502 Tamilnadu, India
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Domenyuk V, Loskutov A, Johnston SA, Diehnelt CW. A technology for developing synbodies with antibacterial activity. PLoS One 2013; 8:e54162. [PMID: 23372679 PMCID: PMC3553175 DOI: 10.1371/journal.pone.0054162] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 12/10/2012] [Indexed: 12/28/2022] Open
Abstract
The rise in antibiotic resistance has led to an increased research focus on discovery of new antibacterial candidates. While broad-spectrum antibiotics are widely pursued, there is evidence that resistance arises in part from the wide spread use of these antibiotics. Our group has developed a system to produce protein affinity agents, called synbodies, which have high affinity and specificity for their target. In this report, we describe the adaptation of this system to produce new antibacterial candidates towards a target bacterium. The system functions by screening target bacteria against an array of 10,000 random sequence peptides and, using a combination of membrane labeling and intracellular dyes, we identified peptides with target specific binding or killing functions. Binding and lytic peptides were identified in this manner and in vitro tests confirmed the activity of the lead peptides. A peptide with antibacterial activity was linked to a peptide specifically binding Staphylococcus aureus to create a synbody with increased antibacterial activity. Subsequent tests showed that this peptide could block S. aureus induced killing of HEK293 cells in a co-culture experiment. These results demonstrate the feasibility of using the synbody system to discover new antibacterial candidate agents.
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Affiliation(s)
- Valeriy Domenyuk
- The Biodesign Institute of Arizona State University, Tempe, Arizona, United States of America
| | - Andrey Loskutov
- The Biodesign Institute of Arizona State University, Tempe, Arizona, United States of America
| | - Stephen Albert Johnston
- The Biodesign Institute of Arizona State University, Tempe, Arizona, United States of America
- School of Life Science, Arizona State University, Tempe, Arizona, United States of America
| | - Chris W. Diehnelt
- The Biodesign Institute of Arizona State University, Tempe, Arizona, United States of America
- * E-mail:
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Novel DNA gyrase inhibitors: Microbiological characterisation of pyrrolamides. Int J Antimicrob Agents 2013; 41:28-35. [DOI: 10.1016/j.ijantimicag.2012.08.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 08/17/2012] [Accepted: 08/27/2012] [Indexed: 11/20/2022]
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Amerasan D, Murugan K, Kovendan K, Mahesh Kumar P, Panneerselvam C, Subramaniam J, John William S, Hwang JS. Adulticidal and repellent properties of Cassia tora Linn. (Family: Caesalpinaceae) against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi. Parasitol Res 2012; 111:1953-64. [PMID: 22821231 DOI: 10.1007/s00436-012-3042-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 07/05/2012] [Indexed: 12/21/2022]
Abstract
Mosquitoes have developed resistance to various synthetic insecticides, making its control increasingly difficult. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. The adulticidal and repellent activities of crude hexane, chloroform, benzene, acetone, and methanol extracts of the leaf of Cassia tora were assayed for their toxicity against three important vector mosquitoes, viz., Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi. The adult mortality was observed after 24 h of exposure. All extracts showed moderate adulticidal effects; however, the highest adult mortality observed was found in methanol extract. The LC(50) and LC(90) values of C. tora leaf extracts against adulticidal activity of (hexane, chloroform benzene, acetone, and methanol) C. quinquefasciatus, A. aegypti, and A. stephensi were the following: C. quinquefasciatus LC(50) values were 338.81, 315.73, 296.13, 279.23, and 261.03 ppm and LC(90) values were 575.77, 539.31, 513.99, 497.06, and 476.03 ppm; A. aegypti LC(50) values were 329.82, 307.31, 287.15, 269.57, and 252.03 ppm and LC(90) values were 563.24, 528.33, 496.92, 477.61, and 448.05 ppm; and A. stephensi LC(50) values were 317.28, 300.30, 277.51, 263.35, and 251.43 ppm and LC(90) values were 538.22, 512.90, 483.78, 461.08, and 430.70 ppm, respectively. The results of the repellent activity of hexane, chloroform, benzene, acetone, and methanol extracts of C. tora plant at three different concentrations of 1.0, 2.5, and 5.0 mg/cm(2) were applied on skin of forearm in man and exposed against adult female mosquitoes. In this observation, this plant crude extracts gave protection against mosquito bites without any allergic reaction to the test person, and also, the repellent activity is dependent on the strength of the plant extracts. These results suggest that the leaf solvent plant extracts have the potential to be used as an ideal eco-friendly approach for the control of mosquitoes. This is the first report on mosquito adulticidal and repellent activities of the reported C. tora against mosquito vectors from Southern India.
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Affiliation(s)
- Duraisamy Amerasan
- Division of Entomology, Department of Zoology, School of Life Sciences, Bharathiar University, Coimbatore, 641 046 Tamil Nadu, India
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Tous S, El Sayed A, Abd El Mohsen M, Youssef E, Agban M, Boushra M. Novel formulation and clinical evaluation of nalidixic acid ointment in impetigo. J Drug Deliv Sci Technol 2012. [DOI: 10.1016/s1773-2247(12)50058-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Identification of pyruvate kinase in methicillin-resistant Staphylococcus aureus as a novel antimicrobial drug target. Antimicrob Agents Chemother 2011; 55:2042-53. [PMID: 21357306 DOI: 10.1128/aac.01250-10] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Novel classes of antimicrobials are needed to address the challenge of multidrug-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA). Using the architecture of the MRSA interactome, we identified pyruvate kinase (PK) as a potential novel drug target based upon it being a highly connected, essential hub in the MRSA interactome. Structural modeling, including X-ray crystallography, revealed discrete features of PK in MRSA, which appeared suitable for the selective targeting of the bacterial enzyme. In silico library screening combined with functional enzymatic assays identified an acyl hydrazone-based compound (IS-130) as a potent MRSA PK inhibitor (50% inhibitory concentration [IC50] of 0.1 μM) with >1,000-fold selectivity over human PK isoforms. Medicinal chemistry around the IS-130 scaffold identified analogs that more potently and selectively inhibited MRSA PK enzymatic activity and S. aureus growth in vitro (MIC of 1 to 5 μg/ml). These novel anti-PK compounds were found to possess antistaphylococcal activity, including both MRSA and multidrug-resistant S. aureus (MDRSA) strains. These compounds also exhibited exceptional antibacterial activities against other Gram-positive genera, including enterococci and streptococci. PK lead compounds were found to be noncompetitive inhibitors and were bactericidal. In addition, mutants with significant increases in MICs were not isolated after 25 bacterial passages in culture, indicating that resistance may be slow to emerge. These findings validate the principles of network science as a powerful approach to identify novel antibacterial drug targets. They also provide a proof of principle, based upon PK in MRSA, for a research platform aimed at discovering and optimizing selective inhibitors of novel bacterial targets where human orthologs exist, as leads for anti-infective drug development.
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Abstract
The discovery of novel small-molecule antibacterial drugs has been stalled for many years. The purpose of this review is to underscore and illustrate those scientific problems unique to the discovery and optimization of novel antibacterial agents that have adversely affected the output of the effort. The major challenges fall into two areas: (i) proper target selection, particularly the necessity of pursuing molecular targets that are not prone to rapid resistance development, and (ii) improvement of chemical libraries to overcome limitations of diversity, especially that which is necessary to overcome barriers to bacterial entry and proclivity to be effluxed, especially in Gram-negative organisms. Failure to address these problems has led to a great deal of misdirected effort.
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Affiliation(s)
- Lynn L Silver
- LL Silver Consulting, LLC, 955 S. Springfield Ave., Unit C403, Springfield, NJ 07081, USA.
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Gwynn MN, Portnoy A, Rittenhouse SF, Payne DJ. Challenges of antibacterial discovery revisited. Ann N Y Acad Sci 2010; 1213:5-19. [PMID: 21058956 DOI: 10.1111/j.1749-6632.2010.05828.x] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The discovery of novel antibiotic classes has not kept pace with the growing threat of bacterial resistance. Antibiotic candidates that act at new targets or via distinct mechanisms have the greatest potential to overcome resistance; however, novel approaches are also associated with higher attrition and longer timelines. This uncertainty has contributed to the withdrawal from antibiotic programs by many pharmaceutical companies. Genomic approaches have not yielded satisfactory results, in part due to nascent knowledge about unprecedented molecular targets, the challenge of achieving antibacterial activity by lead optimization of enzyme inhibitors, and the limitations of compound screening libraries for antibacterial discovery. Enhanced diversity of compound screening banks, entry into new chemical space, and new screening technologies are currently being exploited to improve hit rates for antibacterial discovery. Antibacterial compound lead optimization faces hurdles associated with the high plasma exposures required for efficacy. Lead optimization would be enhanced by the identification of new antibiotic classes with improved tractability and by expanding the predictability of in vitro safety assays. Implementing multiple screening and target identification strategies is recommended for improving the likelihood of discovering new antibacterial compounds that address unmet needs.
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Affiliation(s)
- Michael N Gwynn
- Antibacterial Discovery Performance Unit, Infectious Diseases Center of Excellence for Drug Discovery, GlaxoSmithKline, Collegeville, Pennsylvania, USA
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Suleimana MM, McGaw LJ, Naidoo V, Eloff JN. Detection of antimicrobial compounds by bioautography of different extracts of leaves of selected South African tree species. AFRICAN JOURNAL OF TRADITIONAL, COMPLEMENTARY, AND ALTERNATIVE MEDICINES : AJTCAM 2009; 7:64-78. [PMID: 21304615 PMCID: PMC3005382 DOI: 10.4314/ajtcam.v7i1.57269] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The hexane, acetone, dichloromethane and methanol extracts of Combretum vendae A.E. van Wyk (Combretaceae), Commiphora harveyi (Engl.) Engl. (Burseraceae), Khaya anthotheca (Welm.) C.DC (Meliaceae), Kirkia wilmsii Engl. (Kirkiaceae), Loxostylis alata A. Spreng. ex Rchb. (Anacardiaceae), Ochna natalitia (Meisn.) Walp. (Ochnaceae) and Protorhus longifolia (Bernh. Ex C. Krauss) Engl. (Anacardiaceae) were screened for their antimicrobial activity. The test organisms included bacteria (Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus), and fungi (Aspergillus fumigatus, Candida albicans, Cryptococcus neoformans, Microsporum canis and Sporothrix schenckii). A simple bioautographic procedure, involving spraying suspensions of the bacteria or fungi on thin layer chromatography (TLC) plates developed in solvents of varying polarities was used to detect the number of antibacterial and antifungal compounds present in the extracts. All the extracts had antimicrobial activity against at least one of the test microorganisms. This activity was denoted by white spots against a red-purple background on the TLC plates after spraying with tetrazolium violet. Twenty seven TLC plates; 9 for each solvent system and 3 different solvent systems per organism were tested in the bioautographic procedure. Of the bacteria tested, S. aureus was inhibited by the most compounds separated on the TLC plates from all the tested plants. Similarly, growth of the fungus C. neoformans was also inhibited by many compounds present in the extracts. Loxostylis alata appeared to be the plant extract with the highest number of inhibition bands when compared with other plants tested against both bacteria and fungi. This species was selected for in depth further study.
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Affiliation(s)
- M M Suleimana
- Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, 0110, South Africa
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Ghobrial OG, Derendorf H, Hillman JD. Development and validation of a LC–MS quantification method for the lantibiotic MU1140 in rat plasma. J Pharm Biomed Anal 2009; 49:970-5. [DOI: 10.1016/j.jpba.2008.12.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Accepted: 12/11/2008] [Indexed: 11/26/2022]
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63
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Ruble JC, Hurd AR, Johnson TA, Sherry DA, Barbachyn MR, Toogood PL, Bundy GL, Graber DR, Kamilar GM. Synthesis of (−)-PNU-286607 by Asymmetric Cyclization of Alkylidene Barbiturates. J Am Chem Soc 2009; 131:3991-7. [DOI: 10.1021/ja808014h] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- J. Craig Ruble
- Infectious Diseases Medicinal Chemistry, Pharmacia Corporation, 301 Henrietta Street, Kalamazoo, Michigan 49001, Antibacterial Chemistry, Pfizer Global Research and Development, 2800 Plymouth Road, Ann Arbor Michigan 48105, and Antibacterial Chemistry, Pfizer Global Research and Development, Eastern Point Road, Groton, Connecticut 06340
| | - Alexander R. Hurd
- Infectious Diseases Medicinal Chemistry, Pharmacia Corporation, 301 Henrietta Street, Kalamazoo, Michigan 49001, Antibacterial Chemistry, Pfizer Global Research and Development, 2800 Plymouth Road, Ann Arbor Michigan 48105, and Antibacterial Chemistry, Pfizer Global Research and Development, Eastern Point Road, Groton, Connecticut 06340
| | - Timothy A. Johnson
- Infectious Diseases Medicinal Chemistry, Pharmacia Corporation, 301 Henrietta Street, Kalamazoo, Michigan 49001, Antibacterial Chemistry, Pfizer Global Research and Development, 2800 Plymouth Road, Ann Arbor Michigan 48105, and Antibacterial Chemistry, Pfizer Global Research and Development, Eastern Point Road, Groton, Connecticut 06340
| | - Debra A. Sherry
- Infectious Diseases Medicinal Chemistry, Pharmacia Corporation, 301 Henrietta Street, Kalamazoo, Michigan 49001, Antibacterial Chemistry, Pfizer Global Research and Development, 2800 Plymouth Road, Ann Arbor Michigan 48105, and Antibacterial Chemistry, Pfizer Global Research and Development, Eastern Point Road, Groton, Connecticut 06340
| | - Michael R. Barbachyn
- Infectious Diseases Medicinal Chemistry, Pharmacia Corporation, 301 Henrietta Street, Kalamazoo, Michigan 49001, Antibacterial Chemistry, Pfizer Global Research and Development, 2800 Plymouth Road, Ann Arbor Michigan 48105, and Antibacterial Chemistry, Pfizer Global Research and Development, Eastern Point Road, Groton, Connecticut 06340
| | - Peter L. Toogood
- Infectious Diseases Medicinal Chemistry, Pharmacia Corporation, 301 Henrietta Street, Kalamazoo, Michigan 49001, Antibacterial Chemistry, Pfizer Global Research and Development, 2800 Plymouth Road, Ann Arbor Michigan 48105, and Antibacterial Chemistry, Pfizer Global Research and Development, Eastern Point Road, Groton, Connecticut 06340
| | - Gordon L. Bundy
- Infectious Diseases Medicinal Chemistry, Pharmacia Corporation, 301 Henrietta Street, Kalamazoo, Michigan 49001, Antibacterial Chemistry, Pfizer Global Research and Development, 2800 Plymouth Road, Ann Arbor Michigan 48105, and Antibacterial Chemistry, Pfizer Global Research and Development, Eastern Point Road, Groton, Connecticut 06340
| | - David R. Graber
- Infectious Diseases Medicinal Chemistry, Pharmacia Corporation, 301 Henrietta Street, Kalamazoo, Michigan 49001, Antibacterial Chemistry, Pfizer Global Research and Development, 2800 Plymouth Road, Ann Arbor Michigan 48105, and Antibacterial Chemistry, Pfizer Global Research and Development, Eastern Point Road, Groton, Connecticut 06340
| | - Gregg M. Kamilar
- Infectious Diseases Medicinal Chemistry, Pharmacia Corporation, 301 Henrietta Street, Kalamazoo, Michigan 49001, Antibacterial Chemistry, Pfizer Global Research and Development, 2800 Plymouth Road, Ann Arbor Michigan 48105, and Antibacterial Chemistry, Pfizer Global Research and Development, Eastern Point Road, Groton, Connecticut 06340
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Discovery and characterization of QPT-1, the progenitor of a new class of bacterial topoisomerase inhibitors. Antimicrob Agents Chemother 2008; 52:2806-12. [PMID: 18519725 DOI: 10.1128/aac.00247-08] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
QPT-1 was discovered in a compound library by high-throughput screening and triage for substances with whole-cell antibacterial activity. This totally synthetic compound is an unusual barbituric acid derivative whose activity resides in the (-)-enantiomer. QPT-1 had activity against a broad spectrum of pathogenic, antibiotic-resistant bacteria, was nontoxic to eukaryotic cells, and showed oral efficacy in a murine infection model, all before any medicinal chemistry optimization. Biochemical and genetic characterization showed that the QPT-1 targets the beta subunit of bacterial type II topoisomerases via a mechanism of inhibition distinct from the mechanisms of fluoroquinolones and novobiocin. Given these attributes, this compound represents a promising new class of antibacterial agents. The success of this reverse genomics effort demonstrates the utility of exploring strategies that are alternatives to target-based screens in antibacterial drug discovery.
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66
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Li D, Yang M, Hu J, Zhang Y, Chang H, Jin F. Determination of penicillin G and its degradation products in a penicillin production wastewater treatment plant and the receiving river. WATER RESEARCH 2008; 42:307-17. [PMID: 17675133 DOI: 10.1016/j.watres.2007.07.016] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Revised: 07/11/2007] [Accepted: 07/14/2007] [Indexed: 05/10/2023]
Abstract
To investigate the fate of penicillin G (PEN G) in the wastewater from a PEN G production facility and the receiving river, an analytical method was developed for the simultaneous detection of PEN G and five degradation products using liquid chromatography-electrospray ionization mass spectrometry (LC-ESI/MS). PEN G had already undergone transformation before entering into the wastewater treatment plant (WWTP), with concentrations of 153+/-4 microg/L in raw wastewater. Most of the PEN G could be eliminated following successive treatments of anaerobic, hydrolysis, and two aerobic units under a hydraulic residence time (HRT) of 30 h, and the final concentrations were 1.68+/-0.48 microg/L in treated water. In the receiving river, the concentration of PEN G decreased from 0.31+/-0.04 microg/L at the discharging point to under the detection limit (0.03 microg/L) at the last sampling site (about 30 km from the discharging point). The main PEN G degradation products in surface water were found to be penilloic acid, penicilloic acid and isopenillic acid, which occupied 65.8%, 20.4% and 12.9%, respectively, of the total concentration at the last site. This is the first study on the behaviors of PEN G and its main degradation products in wastewater treatment processes and the aquatic environment.
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Affiliation(s)
- Dong Li
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
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67
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Barbachyn MR. Recent Advances in the Discovery of Hybrid Antibacterial Agents. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2008. [DOI: 10.1016/s0065-7743(08)00017-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
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68
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Bennett BC, Xu H, Simmerman RF, Lee RE, Dealwis CG. Crystal structure of the anthrax drug target, Bacillus anthracis dihydrofolate reductase. J Med Chem 2007; 50:4374-81. [PMID: 17696333 DOI: 10.1021/jm070319v] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Spores of Bacillus anthracis are the infectious agent of anthrax. Current antibiotic treatments are limited due to resistance and patient age restrictions; thus, additional targets for therapeutic intervention are needed. One possible candidate is dihydrofolate reductase (DHFR), a biosynthetic enzyme necessary for anthrax pathogenicity. We determined the crystal structure of DHFR from B. anthracis (baDHFR) in complex with methotrexate (MTX; 1) at 2.4 Angstrom resolution. The structure reveals the crucial interactions required for MTX binding and a putative molecular basis for how baDHFR has natural resistance to trimethoprim (TMP; 2). The structure also allows insights for designing selective baDHFR inhibitors that will have weak affinities for the human enzyme. Additionally, we have found that 5-nitro-6-methylamino-isocytosine (MANIC; 3), which inhibits another B. anthracis folate synthesis enzyme, dihydropteroate synthase (DHPS), can also inhibit baDHFR. This provides a starting point for designing multi-target inhibitors that are less likely to induce drug resistance.
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Affiliation(s)
- Brad C Bennett
- Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, USA
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69
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Braga FG, Bouzada MLM, Fabri RL, de O Matos M, Moreira FO, Scio E, Coimbra ES. Antileishmanial and antifungal activity of plants used in traditional medicine in Brazil. JOURNAL OF ETHNOPHARMACOLOGY 2007; 111:396-402. [PMID: 17234373 DOI: 10.1016/j.jep.2006.12.006] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Revised: 11/25/2006] [Accepted: 12/02/2006] [Indexed: 05/09/2023]
Abstract
The antileishmanial and antifungal activity of 24 methanol extracts from 20 plants, all of them used in the Brazilian traditional medicine for the treatment of several infectious and inflammatory disorders, were evaluated against promastigotes forms of two species of Leishmania (L. amazonensis and L. chagasi) and two yeasts (Candida albicans and Cryptococcus neoformans). Among the 20 tested methanolic extracts, those of Vernonia polyanthes was the most active against L. amazonensis (IC(50) of 4 microg/ml), those of Ocimum gratissimum exhibited the best activity against L. chagasi (IC(50) of 71 microg/ml). Concerning antifungical activity, Schinus terebintifolius, O. gratissimum, Cajanus cajan, and Piper aduncum extracts were the most active against C. albicans (MIC of 1.25 mg/ml) whereas Bixa orellana, O. gratissimum and Syzygium cumini exhibited the best activity against C. neoformans (MIC of 0.078 mg/ml).
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Affiliation(s)
- Fernanda G Braga
- Departamento de Parasitologia, Microbiologia e Imunologia, ICB, Universidade Federal de Juiz de Fora, Juiz de Fora, MG, Brazil
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Esimone CO, Nworu CS, Udeogaranya OP. Utilization of antimicrobial agents with and without prescription by out-patients in selected pharmacies in South-eastern Nigeria. ACTA ACUST UNITED AC 2007; 29:655-60. [PMID: 17464572 DOI: 10.1007/s11096-007-9124-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2006] [Accepted: 03/25/2007] [Indexed: 10/23/2022]
Abstract
OBJECTIVE We conducted a study in out-patient pharmacies in South-eastern Nigeria in order to determine the extent of self-medication of antimicrobial agents in this area, assess the dosing error associated with this practice and to ascertain the extent of involvement of community pharmacies. METHOD A survey was carried out daily in selected community pharmacies for a period of 90 days. Data were collected on the number of patients visiting these shops for antimicrobial agents, the number getting their medication with a prescription, the number getting their order without prescription and on the type and dose of antimicrobial agents received. MAIN OUT-COME MEASURE: The percentage of patients with prescription and without prescription was compared. The percentage under-dosages or over-dosages associated with how each antimicrobial agent was obtained were compared. The total DDDs of antimicrobial agents dispensed within this period with and without prescription were compared. RESULTS A total of 4,128 outpatients visited the shops for antimicrobial agents within the period and were involved in the study. Of this number, 1,742 (42.2%) came with a prescription from qualified medical personnel and 2,386 (57.8%) came without a prescription. A total of 13,693.13 DDDs of antimicrobial agents was dispensed, of which 56.38% was dispensed with prescription and 43.62% was dispensed without prescription. The degrees of under-dosing were significantly (P < 0.05) higher in regimen filled without prescription when compared to those filled with prescription. CONCLUSION Majority of the patients in this region still obtains their antimicrobial agents without a proper prescription, which is associated with sub-therapeutic dosing of these agents. There is a need for better regulation of antimicrobial agents dispensing and utilization in the region.
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Affiliation(s)
- Charles Okey Esimone
- Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, University of Nigeria, Nsukka, 410001, Enugu State, Nigeria
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71
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Abstract
Antibacterial discovery research has been driven, medically, commercially and intellectually, by the need for new therapeutics that are not subject to the resistance mechanisms that have evolved to combat previous generations of antibacterial agents. This need has often been equated with the identification and exploitation of novel targets. But efforts towards discovery and development of inhibitors of novel targets have proved frustrating. It might be that the 'good old targets' are qualitatively different from the crop of all possible novel targets. What has been learned from existing targets that can be applied to the quest for new antibacterials?
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Affiliation(s)
- Lynn L Silver
- LL Silver Consulting, Springfield, New Jersey 07081, USA.
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72
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De La Fuente R, Sonawane ND, Arumainayagam D, Verkman AS. Small molecules with antimicrobial activity against E. coli and P. aeruginosa identified by high-throughput screening. Br J Pharmacol 2006; 149:551-9. [PMID: 16981005 PMCID: PMC2014677 DOI: 10.1038/sj.bjp.0706873] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE New antimicrobials are needed because of the emergence of organisms that are resistant to available antimicrobials. The purpose of this study was to evaluate a high-throughput screening approach to identify antibacterials against two common disease-causing bacteria, and to determine the frequency, novelty, and potency of compounds with antibacterial activity. EXPERIMENTAL APPROACH A high-throughput, turbidometric assay of bacterial growth in a 96-well plate format was used to screen a diverse collection of 150,000 small molecules for antibacterial activity against E. coli and P. aeruginosa. The statistical Z'-factor for the assay was > or = 0.7. KEY RESULTS Screening for inhibition of E. coli growth gave a 'hit' rate (> 60% inhibition at 12.5 microM) of 0.025%, which was more than 5-fold reduced for P. aeruginosa. The most potent antibacterials (EC50 < 0.5 microM) were of the nitrofuran class followed by naphthalimide, salicylanilide, bipyridinium and quinoazolinediamine chemical classes. Screening of > 250 analogs of the most potent antibacterial classes established structure-activity data sets. CONCLUSIONS AND IMPLICATIONS Our results validate and demonstrate the utility of a growth-based phenotype screen for rapid identification of small-molecule antibacterials. The favourable efficacy and structure-activity data for several of the antibacterial classes suggests their potential development for clinical use.
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Affiliation(s)
- R De La Fuente
- Departments of Medicine and Physiology, Cardiovascular Research Institute, University of California San Francisco, CA, USA
| | - N D Sonawane
- Departments of Medicine and Physiology, Cardiovascular Research Institute, University of California San Francisco, CA, USA
| | - D Arumainayagam
- Departments of Medicine and Physiology, Cardiovascular Research Institute, University of California San Francisco, CA, USA
| | - A S Verkman
- Departments of Medicine and Physiology, Cardiovascular Research Institute, University of California San Francisco, CA, USA
- Author for correspondence: http://www.ucsf.edu/verklab
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73
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Janes D, Umek A, Kreft S. Evaluation of antibacterial activity of extracts of five species of wood-colonizing fungi. J Basic Microbiol 2006; 46:203-7. [PMID: 16721880 DOI: 10.1002/jobm.200510035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Screening new organisms for antibacterial activity and searching for new antibacterial drugs is important due to the constant generation of new antibiotic-resistant strains of pathogenic bacteria. An E. coli broth microdilution test was used to evaluate the results of the Vibrio fischeri bioluminescence test in five of the most antibacterially active species of wood-colonizing fungi. Serpula lacrymans was found to be a potential source of thermostable antibiotic(s) and the Vibrio fischeri bioluminescence test was confirmed to be a useful method for screening for antibacterial activity.
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Affiliation(s)
- Damjan Janes
- Faculty of Pharmacy, University of Ljubljana, Askerceva 7, SI-1000 Ljubljana, Slovenia.
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74
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Schmid MB. Crystallizing new approaches for antimicrobial drug discovery. Biochem Pharmacol 2006; 71:1048-56. [PMID: 16458857 DOI: 10.1016/j.bcp.2005.12.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Revised: 12/07/2005] [Accepted: 12/09/2005] [Indexed: 11/29/2022]
Abstract
Over the past decade, the sequences of microbial genomes have accumulated, changing the strategies for the discovery of novel anti-infective agents. Targets have become plentiful, yet new antimicrobial agents have been slow to emerge from this effort. In part, this reflects the long discovery and development times needed to bring new drugs to market. In addition, bottlenecks have been revealed in the antimicrobial drug discovery process at the steps of identifying good leads, and optimizing those leads into drug candidates. The fruit of structural genomics may provide opportunities to overcome these bottlenecks and fill the antimicrobial pipeline, by using the tools of structure guided drug discovery (SGDD).
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Affiliation(s)
- Molly B Schmid
- Keck Graduate Institute, 535 Watson Drive, Claremont, CA 91711, USA.
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75
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76
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Tanji Y, Shimada T, Fukudomi H, Miyanaga K, Nakai Y, Unno H. Therapeutic use of phage cocktail for controlling Escherichia coli O157:H7 in gastrointestinal tract of mice. J Biosci Bioeng 2005; 100:280-7. [PMID: 16243277 DOI: 10.1263/jbb.100.280] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2005] [Accepted: 05/24/2005] [Indexed: 11/17/2022]
Abstract
To investigate the therapeutical use of phage mixture for controlling gastrointestinal Escherichia coli O157:H7 cells, in vitro and in vivo experiments were conducted. Three phages, SP15, SP21, and SP22 were selected from 26 phage stock screened from feces of stock animals and sewage influent. Addition of single or binary phage to the E. coli cell batch-culture reduced the turbidity of the culture. However, reascend of the turbidity due to the appearance of phage resistance cell was observed. On the other hand, addition of three phage mixture (SP15-21-22) did not produce reascend of culture turbidity under aerobic condition. Under anaerobic condition, slight reascend of culture turbidity was observed after SP15-21-22 addition. Chemostat continuous culture was operated under anaerobic condition to optimize the titer of phage cocktail and frequency of the addition for controlling E. coli cells. Five-log decrease of E. coli cell concentration after addition of phage cocktail of 10(9) Plaque forming unit (PFU)/ml was observed. However, reascend of cell concentration was observed after 1 d incubation. Repeated addition of phage cocktail was effective to reduce the cell concentration. Suspension of phage cocktail in the buffer containing 0.25% CaCO3 neutralized 9 times much more buffer of pH 2. Based on this in vitro experiment, phage cocktail (SP15-21-22) suspended in the buffer containing 0.25% CaCO3 was orally administrated to the mice in which E. coli O157:H7 cells was administrated in 2-d advance. E. coli and phage concentration in the feces was monitored for 9 d after phage addition. High titer of phage was detected in the feces when the phage cocktail administrated daily. E. coli O157:H7 concentration in the feces has been reduced according to the time period. However, difference of E. coli concentration in the feces of mice administrates with phage and in the control mice without phage addition became slight after 9-d test period. High titer of the phage settled down in the gastrointestinal tracts and reduced the concentration of E. coli cell. Repeated oral administration of SP15-21-22 was effective for rapid evacuation of E. coli O157:H7 from the feces and gastrointestinal tract of mice.
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Affiliation(s)
- Yasunori Tanji
- Department of Bioengineering, Tokyo Institute of Technology, 4259 B-41 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
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77
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Affiliation(s)
- Dan Kahne
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA.
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78
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Gallant P, Finn J, Keith D, Wendler P. The identification of quality antibacterial drug discovery targets: a case study with aminoacyl-tRNA synthetases. ACTA ACUST UNITED AC 2005. [DOI: 10.1517/14728222.4.1.1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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79
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Schmourlo G, Mendonça-Filho RR, Alviano CS, Costa SS. Screening of antifungal agents using ethanol precipitation and bioautography of medicinal and food plants. JOURNAL OF ETHNOPHARMACOLOGY 2005; 96:563-8. [PMID: 15619579 DOI: 10.1016/j.jep.2004.10.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2004] [Revised: 09/03/2004] [Accepted: 10/06/2004] [Indexed: 05/09/2023]
Abstract
In the search for bioactive compounds, bioautography and ethanol precipitation of macromolecules (proteins, polysaccharides, etc.) of plant aqueous extracts were associated in an antifungal screening. Thus, the supernatants, precipitates (obtained by ethanol precipitation) and aqueous extracts were investigated of medicinal and fruit bearing plants used against skin diseases by the Brazilian population. The agar diffusion and broth dilution methods were used to assess the activity against three fungi: Candida albicans, Trichophyton rubrum and Cryptococcus neoformans. The results, evaluated by the diameter of the inhibition zone of fungal growth, indicate that six plant species, among the 16 investigated, showed significant antifungal activity. The minimal inhibitory concentration (MIC) was determined on plant extracts that showed high efficacy against the tested microorganisms. The most susceptible yeast was Trichophyton rubrum and the best antifungal activity was shown by Xanthosoma sagittifolium supernatant. The bioautography was performed only for the aqueous extracts and supernatants of those plants that showed antifungal activity against Candida albicans and Cryptococcus neoformans, using n-butanol/acetic acid/water (BAW) 8:1:1 to develop silica gel TLC plates. Clear inhibition zones were observed for aqueous extracts of Schinus molle (R(f) 0.89) and Schinus terebinthifolius (R(f) 0.80) against Candida albicans, as for supernatant of Anacardium occidentale (R(f) 0.31) against Cryptococcus neoformans. The separation of macromolecules from metabolites, as in the case of Anacardium occidentale, Solanum sp. and Xanthosoma sagittifolium, enhances antifungal activity. In other cases, the antifungal activity is destroyed, as observed for Momordica charantia, Schinus molle and Schinus terebinthifolius.
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Affiliation(s)
- Gracilene Schmourlo
- Núcleo de Pesquisas de Produtos Naturais, Universidade Federal do Rio de Janeiro (UFRJ), Centro de Ciências da Saúde (CCS), Bloco H, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ 21941-590, Brazil
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80
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81
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Chopra I, Hesse L, O'Neill A. Exploiting current understanding of antibiotic action for discovery of new drugs. J Appl Microbiol 2002. [DOI: 10.1046/j.1365-2672.92.5s1.13.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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82
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DeVito JA, Mills JA, Liu VG, Agarwal A, Sizemore CF, Yao Z, Stoughton DM, Cappiello MG, Barbosa MDFS, Foster LA, Pompliano DL. An array of target-specific screening strains for antibacterial discovery. Nat Biotechnol 2002; 20:478-83. [PMID: 11981561 DOI: 10.1038/nbt0502-478] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
As the global threat of drug- and antibiotic-resistant bacteria continues to rise, new strategies are required to advance the drug discovery process. This work describes the construction of an array of Escherichia coli strains for use in whole-cell screens to identify new antimicrobial compounds. We used the recombination systems from bacteriophages lambda and P1 to engineer each strain in the array for low-level expression of a single, essential gene product, thus making each strain hypersusceptible to specific inhibitors of that gene target. Screening of nine strains from the array in parallel against a large chemical library permitted identification of new inhibitors of bacterial growth. As an example of the target specificity of the approach, compounds identified in the whole-cell screen for MurA inhibitors were also found to block the biochemical function of the target when tested in vitro.
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Affiliation(s)
- Joseph A DeVito
- Department of Antimicrobial Research, Bristol-Myers Squibb Company, Wilmington, DE 19880, USA
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83
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Mandal M, Nagaraj R. Antibacterial activities and conformations of synthetic alpha-defensin HNP-1 and analogs with one, two and three disulfide bridges. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 2002; 59:95-104. [PMID: 11985703 DOI: 10.1034/j.1399-3011.2002.01945.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Structure and biological activities of synthetic peptides corresponding to human alpha-defensin HNP-1, AC1YC2RIPAC3IAGERRYGTC4IYQGRLWAFC5C6 with the S-S connectivities: C1-C6, C2-C4, C3-C5, and its variants with one, two and three disulfide bridges were investigated. Oxidation of synthetic, reduced HNP-1 yielded a peptide with S-S connectivities C1-C3, C2-C4 and C5-C6, and not with the S-S linkages as in naturally occurring HNP-1. Selective protection of cysteine sulfhydryls was necessary for the formation of S-S bridges as in native HNP-1. Likewise, oxidation of peptide encompassing the segment from C2 to C5, resulted in the S-S linkages C2-C3 and C4-C5 instead of the expected linkage C2-C4 and C3-C5. Antibacterial activities were observed for all peptides, irrespective of how the S-S bridges were linked. Linear peptides without S-S bridges were inactive. Circular dichroism (CD) spectra suggest that peptides constrained by one and two S-S bridges do not form rigid beta-sheet structures in an aqueous environment. The spectrum of HNP-1 in an aqueous environment suggests the presence of a beta-hairpin conformation. In the presence of lipid vesicles, the S-S constrained peptides tend to adopt a beta-structure. Although the S-S connectivities observed in HNP-1 may be necessary for other physiological activities, such as chemotaxis, they are clearly not essential for antibacterial activity.
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Affiliation(s)
- M Mandal
- Centre for Cellular and Molecular Biology, Hyderabad, India
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84
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Mandal M, Jagannadham MV, Nagaraj R. Antibacterial activities and conformations of bovine beta-defensin BNBD-12 and analogs:structural and disulfide bridge requirements for activity. Peptides 2002; 23:413-8. [PMID: 11835989 DOI: 10.1016/s0196-9781(01)00628-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Structure and biological activities of synthetic peptides corresponding to bovine neutrophil beta-defensin BNBD-12, GPLSC(1)GRNGGVC(2)IPIRC(3) PVPMRQIGTC(4) FGRPVKC(5) C(6)RSW with disulfide connectivities C(1)-C(5), C(2)-C(4) and C(3)-C(6) and its variants with one, two and three disulfide bridges have been investigated. Selective protection of cysteine thiols was necessary in the four and six cysteine containing peptides for the formation of disulfide connectivities as observed in BNBD-12. Circular dichroism (CD) spectra indicate that in aqueous medium, only a small fraction of molecules populate turn-like conformations. In the presence of micelles and lipid vesicles, the single, two and three disulfide containing peptides adopt beta-hairpin or beta-sheet structures. Antibacterial activity was observed for all the peptides, irrespective of the number of disulfide bridges or how they were connected. Our results suggest that a rigid beta-sheet structure or the presence of three disulfide bridges does not appear to be stringent requirements for antibacterial activity in beta-defensins.
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Affiliation(s)
- M Mandal
- Centre for Cellular and Molecular Biology, Uppal Road, 500 007, Hyderabad, India
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85
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Discovery and development of new anti-bacterial drugs. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s0165-7208(02)80022-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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86
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Mateu E, Martin M. Why is anti-microbial resistance a veterinary problem as well? JOURNAL OF VETERINARY MEDICINE. B, INFECTIOUS DISEASES AND VETERINARY PUBLIC HEALTH 2001; 48:569-81. [PMID: 11708676 DOI: 10.1046/j.1439-0450.2001.00475.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Resistance to anti-microbial agents has become one of the main issues in public health strategies world-wide. Much attention has been paid to the emergence of pathogenic micro-organisms such as enterococci or Salmonella that have developed resistance mechanisms that render them almost untreatable with current antibiotics. One of the alleged reasons for such an emergence is the non-medical use of antibiotics, especially in animals. However, only recently have veterinary forums and journals begun to discuss this topic. On the other hand, anti-microbial resistance has also become a problem in veterinary medicine and the number of reports indicating high rates of resistance among animal-originated micro-organisms is considerable. The present review deals with the mechanisms of resistance known for antibiotics in common veterinary use, the problem of anti-microbial resistance in veterinary medicine and the links between the use of antibiotics in animals and the emergence of anti-microbial resistance in humans.
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Affiliation(s)
- E Mateu
- Departament de Sanitat i Anatomia Animals, UAB, Bellaterra, Spain
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87
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Kawase M, Motohashi N, Sakagami H, Kanamoto T, Nakashima H, Ferenczy L, Wolfard K, Miskolci C, Molnár J. Antimicrobial activity of trifluoromethyl ketones and their synergism with promethazine. Int J Antimicrob Agents 2001; 18:161-5. [PMID: 11516939 DOI: 10.1016/s0924-8579(01)00340-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The antimicrobial effects of 30 trifluoromethyl ketones [1-30] were studied on various representative bacteria. Of the ketones, 4,4,4-trifluoro-1-phenyl-1,3-butanedione [10], 1,1,1-trifluoro-3-(4,5-dimethyloxazol-2-yl)-2-propanone [11] and 1-(2-benzoxazolyl)-3,3,3-trifluoro-2-propanone [18] were found to exhibit potent antibacterial activity against the Gram-positive Bacillus megaterium and Corynebacterium michiganese, but not against Gram-negative bacteria such as Pseudomonas aeruginosa and Serratia marcescens. Compounds 11 and 18 inhibited the Escherichia coli. Compound 18 was also effective against yeasts. The combination of promethazine with 18 was significantly synergistic against E. coli strains, especially the proton pump deficient mutant. The results suggest that membrane transporters are the target of trifluoromethyl ketones. The inhibition was more marked in the proton pump deficient E. coli mutant than in the wild type, which suggested that the antibacterial effect of trifluoromethyl ketones is partly prevented by the proton pump system.
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Affiliation(s)
- M Kawase
- Faculty of Pharmaceutical Sciences, Josai University, Sakado, Saitama 350-0295, Japan.
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88
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Morency H, Mota-Meira M, LaPointe G, Lacroix C, Lavoie MC. Comparison of the activity spectra against pathogens of bacterial strains producing a mutacin or a lantibiotic. Can J Microbiol 2001. [DOI: 10.1139/w01-013] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The increase of drug resistance among bacterial pathogens is currently a major threat in hospital settings. New and more efficient antibiotic compounds have to be developed to fight infectious diseases. In the present work, a deferred antagonism test was used to determine the activity of different bacterial strains producing either a mutacin or a lantibiotic against bacterial pathogens. The mutacins A, B, C, D, I, K, L, M, and nisins A and Z were active against all enterococci tested. Mutacins A and B, and nisins A and Z inhibited all the staphylococci tested. Except for the strains producing mutacins P, Q, and X, all the other producing strains inhibited the streptococci tested. Mutacins A, B, I, J, T, nisins A and Z, and epidermin inhibited the two antibiotic-resistant strains of Neisseria gonorrhoeae tested. Mutacins A, B, C, D, and nisins A and Z inhibited Campylobacter jejuni and Helicobacter pylori. Thus, the wide activity spectra of nisin A and Z are confirmed. These results also indicate that many of the mutacins, especially those of groups A, B, C, D, I, J, K, L, M, and T, could be candidates for further development as useful antibiotics.Key words: mutacin, lantibiotic, bacteriocin, antibiotic.
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89
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Hershberger PM, Demuth TP. Concept, design, and preclinical evaluation of quinolonyl lactam antibacterials. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2001; 456:239-67. [PMID: 10549372 DOI: 10.1007/978-1-4615-4897-3_13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- P M Hershberger
- Procter & Gamble Pharmaceuticals, Health Care Research Center Mason, Ohio 45040, USA
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90
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Affiliation(s)
- A Sulakvelidze
- Division of Molecular Epidemiology, Department of Epidemiology and Preventive Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
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91
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Abstract
So far, two strategies have been applied to develop new anti-infective agents: (a) the synthesis of analogs of classical antibiotics with enhanced activity against resistant pathogens and (b) the screening of naturally occurring substances and libraries of synthetic compounds for antimicrobial activity in whole-cell assays. Today, the same principles are being used; however, the search for antimicrobial compounds with novel modes of action is based on targeting specific resistance and virulence factors. Novel targets for anti-infective agents are currently being discovered as a consequence of a better understanding of cell biology, the molecular basis of bacterial resistance, the gene-pathogenicity relationship and the mechanism of the infection process.
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Affiliation(s)
- E L Setti
- Axys Pharmaceuticals, Inc., South San Francisco, California 94080, USA
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92
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Subbalakshmi C, Nagaraj R, Sitaram N. Biological activities of retro and diastereo analogs of a 13-residue peptide with antimicrobial and hemolytic activities. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 2001; 57:59-67. [PMID: 11168889 DOI: 10.1034/j.1399-3011.2001.00800.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The biological activities of synthetic retro and diastereo analogs of PKLLKTFLSKWIG (SPFK), a 13-residue peptide with antimicrobial and hemolytic activities, have been investigated. Retro peptides with C-terminal acid and amide exhibited antibacterial activities comparable with those of SPFK. Their hemolytic activities were, however, only marginally lower. The diastereo analog with C-terminal acid was not antibacterial and was weakly hemolytic. Amidation of this analog could restore antibacterial activity. Both retro analogs were unordered in aqueous medium but had a propensity for a helical structure in trifluoroethanol. However, diastereo analogs were unordered in both aqueous medium and trifluoroethanol. Thus, reversing the sequence in a short amphiphilic peptide may not always result in the selective loss of biological activity such as hemolytic activity. Also, introduction of enantiomeric amino acids in a short peptide to generate a diastereomer may result in loss of structure as well as antimicrobial and hemolytic activities, unless compensated by an increase in positive charges.
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Affiliation(s)
- C Subbalakshmi
- Centre for Cellular and Molecular Biology, Hyderabad, India
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93
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Houndt T, Ochman H. Long-term shifts in patterns of antibiotic resistance in enteric bacteria. Appl Environ Microbiol 2000; 66:5406-9. [PMID: 11097921 PMCID: PMC92475 DOI: 10.1128/aem.66.12.5406-5409.2000] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Several mechanisms are responsible for the ability of microorganisms to tolerate antibiotics, and the incidence of resistance to these compounds within bacterial species has increased since the commercial use of antibiotics became widespread. To establish the extent of and changes in the diversity of antibiotic resistance patterns in natural populations, we determined the MICs of five antibiotics for collections of enteric bacteria isolated from diverse hosts and geographic locations and during periods before and after commercial application of antibiotics began. All of the pre-antibiotic era strains were susceptible to high levels of these antibiotics, whereas 20% of strains from contemporary populations of Escherichia coli and Salmonella enterica displayed high-level resistance to at least one of the antibiotics. In addition to the increase in the frequency of high-level resistance, background levels, conferred by genes providing nonspecific low-level resistance to multiple antibiotics, were significantly higher among contemporary strains. Changes in the incidence and levels of antibiotic resistance are not confined to particular segments of the bacterial population and reflect responses to the increased exposure of bacteria to antimicrobial compounds over the past several decades.
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Affiliation(s)
- T Houndt
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona 85721, USA
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94
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Russell AD. Mechanisms of bacterial resistance to antibiotics and biocides. PROGRESS IN MEDICINAL CHEMISTRY 2000; 35:133-97. [PMID: 10795401 DOI: 10.1016/s0079-6468(08)70036-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- A D Russell
- Welsh School of Pharmacy, University of Wales, Cardiff, UK
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95
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Alves TM, Silva AF, Brandão M, Grandi TS, Smânia E, Smânia Júnior A, Zani CL. Biological screening of Brazilian medicinal plants. Mem Inst Oswaldo Cruz 2000; 95:367-73. [PMID: 10800195 DOI: 10.1590/s0074-02762000000300012] [Citation(s) in RCA: 185] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In this study, we screened sixty medicinal plant species from the Brazilian savanna ("cerrado") that could contain useful compounds for the control of tropical diseases. The plant selection was based on existing ethnobotanic information and interviews with local healers. Plant extracts were screened for: (a) molluscicidal activity against Biomphalaria glabrata, (b) toxicity to brine shrimp (Artemia salina L.), (c) antifungal activity in the bioautographic assay with Cladosporium sphaerospermum and (d) antibacterial activity in the agar diffusion assay against Staphylococcus aureus, Escherichia coli, Bacillus cereus and Pseudomonas aeruginosa. Forty-two species afforded extracts that showed some degree of activity in one or more of these bioassays.
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Affiliation(s)
- T M Alves
- Laboratório de Química de Produtos Naturais, Centro de Pesquisas René Rachou, Fundação Instituto Oswaldo Cruz, Belo Horizonte, MG, 30190-002, Brasil
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96
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Mota-Meira M, LaPointe G, Lacroix C, Lavoie MC. MICs of mutacin B-Ny266, nisin A, vancomycin, and oxacillin against bacterial pathogens. Antimicrob Agents Chemother 2000; 44:24-9. [PMID: 10602718 PMCID: PMC89623 DOI: 10.1128/aac.44.1.24-29.2000] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Peptide antibiotics, particularly lantibiotics, are good candidates for replacing antibiotics to which bacteria have become resistant. In order to compare two such lantibiotics with two antibiotics, the MICs of nisin A, mutacin B-Ny266, vancomycin, and oxacillin against various bacterial pathogens were determined. The results indicate that nisin A and mutacin B-Ny266 are as active as vancomycin and oxacillin against most of the strains tested. Furthermore, mutacin B-Ny266 remains active against strains that are resistant to nisin A, oxacillin, or vancomycin. The wide spectrum of activity of mutacin B-Ny266, its low MICs against bacterial pathogens, and its activity against bacteria resistant to other inhibitors support the development of this substance for therapeutic use.
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Affiliation(s)
- M Mota-Meira
- Centre de Recherche en Sciences et Technologie du Lait (STELA), Faculté des Sciences de l'Agriculture et de l'Alimentation, Université Laval, Cité Universitaire, Québec, Québec, Canada G1K 7P4
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97
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Ho II, Chan CY, Cheng AF. Aminoglycoside resistance in Mycobacterium kansasii, Mycobacterium avium-M. intracellulare, and Mycobacterium fortuitum: are aminoglycoside-modifying enzymes responsible? Antimicrob Agents Chemother 2000; 44:39-42. [PMID: 10602720 PMCID: PMC89625 DOI: 10.1128/aac.44.1.39-42.2000] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aminoglycoside acetyltransferase was detected in Mycobacterium kansasii and M. fortuitum but not in M. avium-M. intracellulare when they were screened by a radioassay. Aminoglycoside phosphotransferase and nucleotidyltransferase activities were absent from all three species tested. Acetyltransferases from both M. kansasii and M. fortuitum displayed relatively high K(m)s, all at the millimolar level, for substrates including tobramycin, neomycin, and kanamycin A. The K(m) of each substrate was well above the corresponding maximum achievable level in serum. The low affinities of these enzymes for their substrates suggested that drug modification in vivo was very unlikely. Among the various substrates tested, no apparent positive correlation was found between substrate affinity and resistance level. The presence of aminoglycoside-modifying enzymes in these mycobacterial species was therefore not shown to confer resistance to aminoglycosides.
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Affiliation(s)
- I I Ho
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, N.T., Hong Kong, China
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98
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Barbachyn MR, Brickner SJ, Gadwood RC, Garmon SA, Grega KC, Hutchinson DK, Munesada K, Reischer RJ, Taniguchi M, Thomasco LM, Toops DS, Yamada H, Ford CW, Zurenko GE. Design, synthesis, and evaluation of novel oxazolidinone antibacterial agents active against multidrug-resistant bacteria. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1999; 456:219-38. [PMID: 10549371 DOI: 10.1007/978-1-4615-4897-3_12] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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99
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Barros JC, Pinheiro SR, Bozza M, Gueiros-Filho FJ, Bello AR, Lopes UG, Pereira JA. Evidences of gentamicin resistance amplification in Klebsiella pneumoniae isolated from faeces of hospitalized newborns. Mem Inst Oswaldo Cruz 1999; 94:795-802. [PMID: 10585658 DOI: 10.1590/s0074-02761999000600016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The intestinal microbiota, a barrier to the establishment of pathogenic bacteria, is also an important reservoir of opportunistic pathogens. It plays a key role in the process of resistance-genes dissemination, commonly carried by specialized genetic elements, like plasmids, phages, and conjugative transposons. We obtained from strains of enterobacteria, isolated from faeces of newborns in a university hospital nursery, indication of phenotypical gentamicin resistance amplification (frequencies of 10(-3) to 10(-5), compatible with transposition frequencies). Southern blotting assays showed strong hybridization signals for both plasmidial and chromosomal regions in DNA extracted from variants selected at high gentamicin concentrations, using as a probe a labeled cloned insert containing aminoglycoside modifying enzyme (AME) gene sequence originated from a plasmid of a Klebsiella pneumoniae strain previously isolated in the same hospital. Further, we found indications of inactivation to other resistance genes in variants selected under similar conditions, as well as, indications of co-amplification of other AME markers (amikacin). Since the intestinal environment is a scenario of selective processes due to the therapeutic and prophylactic use of antimicrobial agents, the processes of amplification of low level antimicrobial resistance (not usually detected or sought by common methods used for antibiotic resistance surveillance) might compromise the effectiveness of antibiotic chemotherapy.
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Affiliation(s)
- J C Barros
- Departamento de Patologia e Laboratórios, Faculdade de Ciências Médicas, UERJ, Rio de Janeiro, RJ, 20551-030, Brasil
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100
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Araque M, Velazco E. In vitro activity of fleroxacin against multiresistant gram-negative bacilli isolated from patients with nosocomial infections. Intensive Care Med 1998; 24:839-44. [PMID: 9757930 DOI: 10.1007/s001340050675] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In order to evaluate the in vitro activity of fleroxacin against nosocomial gram-negative organisms, 263 multiresistant gram-negative bacilli (203 Enterobacteriaceae and 60 non-fermenting gram-negative bacilli) were isolated from adult patients with nosocomial infections. The different patterns of resistance to eight different antimicrobial agents (ampicillin, carbenicillin, piperacillin, cephalothin, cefamandole, ceftazidime, gentamicin and amikacin) were determined by minimum inhibitory concentration (MIC), using the agar dilution method. The most prevalent multiresistant species isolated were Klebsiella pneumoniae (28.9%), Escherichia coli (24%) and Pseudomonas aeruginosa (12.2%). All these bacterial strains showed three to five resistance patterns to at least three different antibiotics. Resistance to ceftazidime was observed in at least one of the resistance patterns of isolated bacteria. The activity of fleroxacin against multiresistant enteric bacteria was excellent; these strains showed a susceptibility of 79-100%. The susceptibility of P. aeruginosa to antipseudomonal agents was low; however, the activity of fleroxacin against these strains was higher than 60% (MIC < or = 2 microg/ ml), broadly comparable with ciprofloxacin. The resistance to fluoroquinolones detected in this study was no cause for alarm (3%). Consequently, fleroxacin maintains a remarkable activity against Enterobacteriaceae and remains highly active against other gram-negative bacilli. Nevertheless, actions directed at preventing or limiting resistance will be crucial to maintain the viability of fluoroquinolones as important therapeutic agents.
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Affiliation(s)
- M Araque
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of The Andes, Mérida, Venezuela
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