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Li D, Li J, Xu Y, Ling C, Qiu Y, Zhu Z, Liu Z. Topical vancomycin powder for the prevention of surgical site infections in spinal deformity surgery: a systematic review and meta-analysis. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2024:10.1007/s00586-024-08494-1. [PMID: 39269667 DOI: 10.1007/s00586-024-08494-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2024] [Revised: 09/05/2024] [Accepted: 09/10/2024] [Indexed: 09/15/2024]
Abstract
PURPOSE To assess the effectiveness and safety of topical vancomycin powder (VP) in preventing surgical site infections (SSIs) in spinal deformity surgeries. METHODS A literature search was conducted on Web of Science, PubMed, and Cochrane Library databases for comparative studies of VP in spinal deformity surgeries published before February 2024. Two reviewers independently screened eligible articles based on the inclusion and exclusion criteria, assessed study quality, and extracted data. Data analysis was performed using Review Manager 5.4 software. RESULTS Of all 143 papers screened, a meta-analysis was conducted on 10 articles, which included a total of 8,166 surgeries. The results of the meta-analysis indicated that the incidence of deep SSI in VP group was 0.28 times that in non-VP group (p < 0.001). In the subgroup analysis, VP treatment significantly reduced the risk of deep SSI in both adult spinal deformity (ASD) (RR 0.40, 95% CI 0.21-0.77, p = 0.006) and pediatric scoliosis (PS) (RR 0.25, 95% CI 0.16-0.38, p < 0.001) surgeries. However, this effect was not observed in neuromuscular scoliosis (NMS) patients (RR 0.66, 95% CI 0.26-1.66, p = 0.38). Bacterial culture results indicated that VP treatment significantly reduced polymicrobial infections (p = 0.007) and gram-positive infections (p = 0.001). CONCLUSION From the literature available at present, VP was associated with reduced deep SSIs rates in spinal deformity patients. However, particular attention should be paid to the lack of the effectiveness of VP in NMS patients. The current literature did not report local cytotoxicity or renal toxicity related to VP in spinal deformity patients.
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Affiliation(s)
- Dong Li
- Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing University, Zhongshan Road 321, Nanjing, 210008, China
| | - Jie Li
- Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing University, Zhongshan Road 321, Nanjing, 210008, China
| | - Yanjie Xu
- Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing University, Zhongshan Road 321, Nanjing, 210008, China
| | - Chen Ling
- Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, Clinical College of Jiangsu University, Nanjing, 210008, China
| | - Yong Qiu
- Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing University, Zhongshan Road 321, Nanjing, 210008, China
| | - Zezhang Zhu
- Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing University, Zhongshan Road 321, Nanjing, 210008, China
| | - Zhen Liu
- Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing University, Zhongshan Road 321, Nanjing, 210008, China.
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Ramezanifard R, Golubeva YA, Palmer AD, Slauch JM. TamAB is regulated by PhoPQ and functions in outer membrane homeostasis during Salmonella pathogenesis. J Bacteriol 2023; 205:e0018323. [PMID: 37728604 PMCID: PMC10601761 DOI: 10.1128/jb.00183-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 07/12/2023] [Indexed: 09/21/2023] Open
Abstract
Salmonella survive and replicate in macrophages, which normally kill bacteria by exposing them to a variety of harsh conditions and antimicrobial effectors, many of which target the bacterial cell envelope. The PhoPQ two-component system responds to the phagosome environment and induces factors that protect the outer membrane, allowing adaptation and growth in the macrophage. We show that PhoPQ induces the transcription of the tamAB operon both in vitro and in macrophages. The TamA protein is structurally similar to BamA, an essential protein in the Bam complex that assembles β-barrel proteins in the outer membrane, while TamB is an AsmA-family protein implicated in lipid transport between the inner and outer membranes. We show that the Bam machinery is stressed in vitro under low Mg2+, low pH conditions that mimic the phagosome. Not surprisingly, mutations affecting Bam function confer significant virulence defects. Although loss of TamAB alone confers no virulence defect, a tamAB deletion confers a synthetic phenotype in bam mutant backgrounds in animals and macrophages, and in vitro upon treatment with vancomycin or sodium dodecyl sulfate. Mutations affecting YhdP, which functions in partial redundancy with TamB, also confer synthetic phenotypes with bam mutations in the animal, but this interaction is not evident in vitro. Thus, in the harsh phagocytic environment of the macrophage, the outer membrane Bam machinery is compromised, and the TamAB system, and perhaps other PhoPQ-regulated factors, is induced to compensate. It is most likely that TamAB and other systems assist the Bam complex indirectly by affecting outer membrane properties. IMPORTANCE The TamAB system has been implicated in both outer membrane protein localization and phospholipid transport between the inner and outer membranes. We show that the β-barrel protein assembly complex, Bam, is stressed under conditions thought to mimic the macrophage phagosome. TamAB expression is controlled by the PhoPQ two-component system and induced in macrophages. This system somehow compensates for the Bam complex as evidenced by the fact that mutations affecting the two systems confer synthetic phenotypes in animals, macrophages, and in vitro in the presence of vancomycin or SDS. This study has implications concerning the role of TamAB in outer membrane homeostasis. It also contributes to our understanding of the systems necessary for Salmonella to adapt and reproduce within the macrophage phagosome.
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Affiliation(s)
- Rouhallah Ramezanifard
- Department of Microbiology, University of Illinois at Urbana Champaign, Urbana, Illinois, USA
| | - Yekaterina A. Golubeva
- Department of Microbiology, University of Illinois at Urbana Champaign, Urbana, Illinois, USA
| | - Alexander D. Palmer
- Department of Microbiology, University of Illinois at Urbana Champaign, Urbana, Illinois, USA
| | - James M. Slauch
- Department of Microbiology, University of Illinois at Urbana Champaign, Urbana, Illinois, USA
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Harpaz D, Barhom H, Veltman B, Ginzburg P, Eltzov E. Biocompatibility characterization of vaterite with a bacterial whole-cell biosensor. Colloids Surf B Biointerfaces 2023; 222:113104. [PMID: 36584449 DOI: 10.1016/j.colsurfb.2022.113104] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 11/28/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022]
Abstract
The growing biomedical challenges impose the continuous development of novel platforms. Ensuring the biocompatibility of drug delivery and implantable biomedical devices is an essential requirement. Calcium carbonate (CaCO3) in the form of vaterite nanoparticles is a promising platform, which has demonstrated distinctive optical and biochemical properties, including high porosity and metastability. In this study, the biocompatibility of differently shaped CaCO3 vaterite particles (toroids, ellipsoids, and spheroids) are evaluated by bacterial toxicity mode-of-action with a whole-cell biosensor. Different Escherichia coli (E. coli) strains were used in the bioluminescent assay, including cytotoxicity, genotoxicity and quorum-sensing. Firstly, both scanning electron microscopy (SEM) and fluorescence microscopy characterizations were conducted. Bacterial cell death and aggregates were observed only in the highest tested concentration of the vaterite particles, especially in toroids 15-25 µm. After, the bioluminescent bacterial panel was exposed to the vaterite particles, and their bioluminescent signal reflected their toxicity mode-of-action. The vaterite particles resulted in an induction factor (IF > 1) on the bacterial panel, which was higher after exposure to the toroids (1.557 ≤ IF ≤ 2.271) and ellipsoids particles (1.712 ≤ IF ≤ 2.018), as compared to the spheroids particles (1.134 ≤ IF ≤ 1.494), in all the tested bacterial strains. Furthermore, the vaterite particles did not affect the viability of the bacterial cells. The bacterial monitoring demonstrated the biofriendly nature of especially spheroids vaterite nanoparticles.
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Affiliation(s)
- Dorin Harpaz
- Institute of Postharvest and Food Science, Department of Postharvest Science, Volcani Institute, Agricultural Research Organization, Rishon LeZion 7505101, Israel; Institute of Biochemistry, Food Science and Nutrition, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
| | - Hani Barhom
- School of Electrical Engineering, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Boris Veltman
- Institute of Postharvest and Food Science, Department of Postharvest Science, Volcani Institute, Agricultural Research Organization, Rishon LeZion 7505101, Israel; Institute of Biochemistry, Food Science and Nutrition, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
| | - Pavel Ginzburg
- School of Electrical Engineering, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Evgeni Eltzov
- Institute of Postharvest and Food Science, Department of Postharvest Science, Volcani Institute, Agricultural Research Organization, Rishon LeZion 7505101, Israel; Agro-Nanotechnology and Advanced Materials Research Center, Volcani Institute, Agricultural Research Organization, Rishon LeZion 7505101, Israel.
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Harpaz D, Veltman B, Katz D, Eltzov E. Whole-cell bacterial biosensor with the capability to detect red palm weevil, Rhynchophorus ferrugineus, in date palm trees, Phoenix dactylifera: a proof of concept study. J Biotechnol 2022; 357:47-55. [PMID: 35963593 DOI: 10.1016/j.jbiotec.2022.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 08/09/2022] [Indexed: 11/16/2022]
Abstract
The red palm weevil (RPW), Rhynchophorus ferrugineus, is considered a severe pest of palms. Usually, the early stages of infection are without visible signs. An attractive early sensing approach of non-visible infections is based on volatile organic compounds (VOCs). In this study, a whole-cell bacterial biosensor was used for the identification of RPW in date palm (Phoenix dactylifera). The cells are genetically modified to produce light in the presence of general stresses. The bioluminescent bacterial panel is based on three genetically engineered Escherichia coli strains that are sensitive to cytotoxicity (TV1061), genotoxicity (DPD2794), or quorum-sensing (K802NR). The bioluminescent bacterial panel detects the presence of VOCs and a change in the light signal is then generated, reflecting the health status of the date palm tree. The bioreporter bacteria cells are immobilized in calcium alginate tablets and placed in a sealed jar without direct contact with the tested sample, thereby exposing them only to the VOCs in the surrounding air. The immobilized bacteria cells were exposed to the air near infected by RPW or uninfected sugar canes, date palm tree pieces, and on date palm trees. Commercial plate reader was used for signal measurement. The findings show that quorum-sensing was induced by all the tested samples of infected sugar canes, date palm tree pieces, and date palm trees. While, cytotoxicity was induced only by infected date palm tree pieces, and genotoxicity was induced only by infected date palm trees. The bacterial monitoring results enable the identification of specific signatures that will allow a quick and accurate diagnosis.
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Affiliation(s)
- Dorin Harpaz
- Institute of Postharvest and Food Science, Department of Postharvest Science, Volcani Institute, Agricultural Research Organization, Rishon LeZion 7505101, Israel; Institute of Biochemistry, Food Science and Nutrition, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
| | - Boris Veltman
- Institute of Postharvest and Food Science, Department of Postharvest Science, Volcani Institute, Agricultural Research Organization, Rishon LeZion 7505101, Israel; Institute of Biochemistry, Food Science and Nutrition, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
| | - Daniel Katz
- Eden Farm, Agricultural R&D center, Emek HaMa'ayanot Regional Council, Beit Shean Valley 171000, Israel.
| | - Evgeni Eltzov
- Institute of Postharvest and Food Science, Department of Postharvest Science, Volcani Institute, Agricultural Research Organization, Rishon LeZion 7505101, Israel.
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van Groesen E, Innocenti P, Martin NI. Recent Advances in the Development of Semisynthetic Glycopeptide Antibiotics: 2014-2022. ACS Infect Dis 2022; 8:1381-1407. [PMID: 35895325 PMCID: PMC9379927 DOI: 10.1021/acsinfecdis.2c00253] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The accelerated appearance of drug-resistant bacteria poses an ever-growing threat to modern medicine's capacity to fight infectious diseases. Gram-positive species such as methicillin-resistant Staphylococcus aureus (MRSA) and Streptococcus pneumoniae continue to contribute significantly to the global burden of antimicrobial resistance. For decades, the treatment of serious Gram-positive infections relied upon the glycopeptide family of antibiotics, typified by vancomycin, as a last line of defense. With the emergence of vancomycin resistance, the semisynthetic glycopeptides telavancin, dalbavancin, and oritavancin were developed. The clinical use of these compounds is somewhat limited due to toxicity concerns and their unusual pharmacokinetics, highlighting the importance of developing next-generation semisynthetic glycopeptides with enhanced antibacterial activities and improved safety profiles. This Review provides an updated overview of recent advancements made in the development of novel semisynthetic glycopeptides, spanning the period from 2014 to today. A wide range of approaches are covered, encompassing innovative strategies that have delivered semisynthetic glycopeptides with potent activities against Gram-positive bacteria, including drug-resistant strains. We also address recent efforts aimed at developing targeted therapies and advances made in extending the activity of the glycopeptides toward Gram-negative organisms.
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Affiliation(s)
- Emma van Groesen
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University 2333 BE Leiden, The Netherlands
| | - Paolo Innocenti
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University 2333 BE Leiden, The Netherlands
| | - Nathaniel I Martin
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University 2333 BE Leiden, The Netherlands
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Veltman B, Harpaz D, Melamed S, Tietel Z, Tsror L, Eltzov E. Whole-cell bacterial biosensor for volatile detection from Pectobacterium-infected potatoes enables early identification of potato tuber soft rot disease. Talanta 2022; 247:123545. [PMID: 35597022 DOI: 10.1016/j.talanta.2022.123545] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 05/08/2022] [Accepted: 05/10/2022] [Indexed: 11/26/2022]
Abstract
Half of the harvested food is lost due to rots caused by microorganisms. Plants emit various volatile organic compounds (VOCs) into their surrounding environment, and the VOC profiles of healthy crops are altered upon infection. In this study, a whole-cell bacterial biosensor was used for the early identification of potato tuber soft rot disease caused by the pectinolytic bacteria Pectobacterium in potato tubers. The detection is based on monitoring the luminescent responses of the bacteria panel to changes in the VOC profile following inoculation. First, gas chromatography-mass spectrometry (GC-MS) was used to specify the differences between the VOC patterns of the inoculated and non-inoculated potato tubers during early infection. Five VOCs were identified, 1-octanol, phenylethyl alcohol, 2-ethyl hexanol, nonanal, and 1-octen-3-ol. Then, the infection was detected by the bioreporter bacterial panel, firstly measured in a 96-well plate in solution, and then also tested in potato plugs and validated in whole tubers. Examination of the bacterial panel responses showed an extensive cytotoxic effect over the testing period, as seen by the elevated induction factor (IF) values in the bacterial strain TV1061 after exposure to both potato plugs and whole tubers. Moreover, quorum sensing influences were also observed by the elevated IF values in the bacterial strain K802NR. The developed whole-cell biosensor system based on bacterial detection will allow more efficient crop management during postharvest, storage, and transport of crops, to reduce food losses.
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Affiliation(s)
- Boris Veltman
- Institute of Postharvest and Food Science, Department of Postharvest Science, Volcani Institute, Agricultural Research Organization, Rishon LeZion, 7505101, Israel; Institute of Biochemistry, Food Science and Nutrition, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel.
| | - Dorin Harpaz
- Institute of Postharvest and Food Science, Department of Postharvest Science, Volcani Institute, Agricultural Research Organization, Rishon LeZion, 7505101, Israel; Institute of Biochemistry, Food Science and Nutrition, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel.
| | - Sarit Melamed
- Department of Food Science, Gilat Research Center, Agricultural Research Organization, M.P, Negev, 8531100, Israel.
| | - Zipora Tietel
- Department of Food Science, Gilat Research Center, Agricultural Research Organization, M.P, Negev, 8531100, Israel.
| | - Leah Tsror
- Department of Plant Pathology and Weed Research, Institute of Plant Protection, Gilat Research Center, Agricultural Research Organization, M.P, Negev, 8531100, Israel.
| | - Evgeni Eltzov
- Institute of Postharvest and Food Science, Department of Postharvest Science, Volcani Institute, Agricultural Research Organization, Rishon LeZion, 7505101, Israel.
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7
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Newman DJ. Old and modern antibiotic structures with potential for today's infections. ADMET AND DMPK 2022; 10:131-146. [PMID: 35350115 PMCID: PMC8957243 DOI: 10.5599/admet.1272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/13/2022] [Indexed: 11/21/2022] Open
Abstract
Due to the lack of new antibiotics with efficacy against the ESKAPE and other resistant microbes, coupled to the demise of major pharmaceutical company antibiotic discovery programs, due to a number of factors but mainly ROI calculations and the lack of efficacy of combinatorial chemistry as a substitute, the search for novel antibiotics may well have moved to the utilization of older structures with significant synthetic chemistry input. This short review demonstrates how modern synthetic chemistry, when applied to either modification of current resistant antibiotics such as glycopeptides, or production of novel peptidic agents based on natural product sourced antimicrobial peptides (AMPs) and other potential initial peptide-based agents from genomic searches and baiting techniques, have produced active agents of significant utility. In addition, synthetic chemistry practitioners have now shown that they can produce bioactive molecules of greater than 800 Daltons in kilogram quantities under cGMP conditions.
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Lertsuphotvanit N, Santimaleeworagun W, Narakornwit W, Chuenbarn T, Mahadlek J, Chantadee T, Phaechamud T. Borneol-based antisolvent-induced in situ forming matrix for crevicular pocket delivery of vancomycin hydrochloride. Int J Pharm 2022; 617:121603. [DOI: 10.1016/j.ijpharm.2022.121603] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 01/23/2022] [Accepted: 02/16/2022] [Indexed: 01/31/2023]
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9
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van Groesen E, Slingerland CJ, Innocenti P, Mihajlovic M, Masereeuw R, Martin NI. Vancomyxins: Vancomycin-Polymyxin Nonapeptide Conjugates That Retain Anti-Gram-Positive Activity with Enhanced Potency against Gram-Negative Strains. ACS Infect Dis 2021; 7:2746-2754. [PMID: 34387988 PMCID: PMC8438664 DOI: 10.1021/acsinfecdis.1c00318] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
![]()
Vancomycin functions
by binding to lipid II, the penultimate bacterial
cell wall building block used by both Gram-positive and Gram-negative
species. However, vancomycin is generally only able to exert its antimicrobial
effect against Gram-positive strains as it cannot pass the outer membrane
(OM) of Gram-negative bacteria. To address this challenge, we here
describe efforts to conjugate vancomycin to the OM disrupting polymyxin
E nonapeptide (PMEN) to yield the hybrid “vancomyxins”.
In designing these hybrid antibiotics, different spacers and conjugation
sites were explored for connecting vancomycin and PMEN. The vancomyxins
show improved activity against Gram-negative strains compared with
the activity of vancomycin or vancomycin supplemented with PMEN separately.
In addition, the vancomyxins maintain the antimicrobial effect of
vancomycin against Gram-positive strains and, in some cases, show
enhanced activity against vancomycin-resistant strains. The hybrid
antibiotics described here have reduced nephrotoxicity when compared
with clinically used polymyxin antibiotics. This study demonstrates
that covalent conjugation to an OM disruptor contributes to sensitizing
Gram-negative strains to vancomycin while retaining anti-Gram-positive
activity.
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Affiliation(s)
- Emma van Groesen
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Cornelis J. Slingerland
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Paolo Innocenti
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Milos Mihajlovic
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Rosalinde Masereeuw
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Nathaniel I. Martin
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
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Hou YM, Masuda I, Foster LJ. tRNA methylation: An unexpected link to bacterial resistance and persistence to antibiotics and beyond. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 11:e1609. [PMID: 32533808 DOI: 10.1002/wrna.1609] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/06/2020] [Accepted: 05/07/2020] [Indexed: 02/02/2023]
Abstract
A major threat to public health is the resistance and persistence of Gram-negative bacteria to multiple drugs during antibiotic treatment. The resistance is due to the ability of these bacteria to block antibiotics from permeating into and accumulating inside the cell, while the persistence is due to the ability of these bacteria to enter into a nonreplicating state that shuts down major metabolic pathways but remains active in drug efflux. Resistance and persistence are permitted by the unique cell envelope structure of Gram-negative bacteria, which consists of both an outer and an inner membrane (OM and IM, respectively) that lay above and below the cell wall. Unexpectedly, recent work reveals that m1 G37 methylation of tRNA, at the N1 of guanosine at position 37 on the 3'-side of the tRNA anticodon, controls biosynthesis of both membranes and determines the integrity of cell envelope structure, thus providing a novel link to the development of bacterial resistance and persistence to antibiotics. The impact of m1 G37-tRNA methylation on Gram-negative bacteria can reach further, by determining the ability of these bacteria to exit from the persistence state when the antibiotic treatment is removed. These conceptual advances raise the possibility that successful targeting of m1 G37-tRNA methylation can provide new approaches for treating acute and chronic infections caused by Gram-negative bacteria. This article is categorized under: Translation > Translation Regulation RNA Processing > RNA Editing and Modification RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems.
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Affiliation(s)
- Ya-Ming Hou
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Isao Masuda
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Leonard J Foster
- Department of Biochemistry & Molecular Biology, and Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
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Klobucar K, French S, Côté JP, Howes JR, Brown ED. Genetic and Chemical-Genetic Interactions Map Biogenesis and Permeability Determinants of the Outer Membrane of Escherichia coli. mBio 2020; 11:e00161-20. [PMID: 32156814 PMCID: PMC7064757 DOI: 10.1128/mbio.00161-20] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 01/29/2020] [Indexed: 02/08/2023] Open
Abstract
Gram-negative bacteria are intrinsically resistant to many antibiotics due to their outer membrane barrier. Although the outer membrane has been studied for decades, there is much to uncover about the biology and permeability of this complex structure. Investigating synthetic genetic interactions can reveal a great deal of information about genetic function and pathway interconnectivity. Here, we performed synthetic genetic arrays (SGAs) in Escherichia coli by crossing a subset of gene deletion strains implicated in outer membrane permeability with nonessential gene and small RNA (sRNA) deletion collections. Some 155,400 double-deletion strains were grown on rich microbiological medium with and without subinhibitory concentrations of two antibiotics excluded by the outer membrane, vancomycin and rifampin, to probe both genetic interactions and permeability. The genetic interactions of interest were synthetic sick or lethal (SSL) gene deletions that were detrimental to the cell in combination but had a negligible impact on viability individually. On average, there were ∼30, ∼36, and ∼40 SSL interactions per gene under no-drug, rifampin, and vancomycin conditions, respectively; however, many of these involved frequent interactors. Our data sets have been compiled into an interactive database called the Outer Membrane Interaction (OMI) Explorer, where genetic interactions can be searched, visualized across the genome, compared between conditions, and enriched for gene ontology (GO) terms. A set of SSL interactions revealed connectivity and permeability links between enterobacterial common antigen (ECA) and lipopolysaccharide (LPS) of the outer membrane. This data set provides a novel platform to generate hypotheses about outer membrane biology and permeability.IMPORTANCE Gram-negative bacteria are a major concern for public health, particularly due to the rise of antibiotic resistance. It is important to understand the biology and permeability of the outer membrane of these bacteria in order to increase the efficacy of antibiotics that have difficulty penetrating this structure. Here, we studied the genetic interactions of a subset of outer membrane-related gene deletions in the model Gram-negative bacterium E. coli We systematically combined these mutants with 3,985 nonessential gene and small RNA deletion mutations in the genome. We examined the viability of these double-deletion strains and probed their permeability characteristics using two antibiotics that have difficulty crossing the outer membrane barrier. An understanding of the genetic basis for outer membrane integrity can assist in the development of new antibiotics with favorable permeability properties and the discovery of compounds capable of increasing outer membrane permeability to enhance the activity of existing antibiotics.
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Affiliation(s)
- Kristina Klobucar
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Shawn French
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Jean-Philippe Côté
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - James R Howes
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Eric D Brown
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
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12
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Kim S, Jo S, Kim MS, Shin DH. A Study of a Potent Inhibitor Against a GDP-6-Deoxy-α-d- Manno-Heptose Biosynthesis Pathway as Antibiotic Candidates. Microb Drug Resist 2019; 26:385-390. [PMID: 31613705 DOI: 10.1089/mdr.2019.0144] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The GDP-6-deoxy-α-d-manno-heptose is a key building block molecule in constructing lipopolysaccharide of Gram-negative bacteria. Therefore, blockage of the biosynthesis pathway of GDP-6-deoxy-α-d-manno-heptose is lethal or increases antibiotics susceptibility to pathogens. In this study, we assayed d-glycero-α-d-manno-heptose-1-phosphate guanylyltransferase (HddC) from Yersinia pseudotuberculosis (Yp) using an efficient assay method supplying its natural substrate. Using the method, 102 chemical compounds were tested to search inhibitory compounds and electrospray ionization mass spectrometry was used to detect the HddC from Y. pseudotuberculosis (YpHddC) reaction product, GDP-d-glycero-α-d-manno-heptose. Interestingly, one promising lead, ethyl 5-({[(5-benzyl-1, 3, 4-oxadiazol-2-yl) thio] acetyl} amino)-4-cyano-3-methyl-2-thiophenecarboxylate (Chembridge 7929959), was discovered. The inhibitory activity of the lead compound against YpHddC has been proven by blocking its nucleotidyltransferase activity transferring the GMP moiety to α-d-mannose-1-phosphate (αM1P). Chembridge 7929959 shows that the half maximal inhibitory concentration (IC50) is 0.222 μM indicating its affinity with αM1P.
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Affiliation(s)
- Suwon Kim
- Department of pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, Republic of Korea
| | - Seri Jo
- Department of pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, Republic of Korea
| | - Mi-Sun Kim
- Department of pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, Republic of Korea
| | - Dong Hae Shin
- Department of pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, Republic of Korea
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13
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Masuda I, Matsubara R, Christian T, Rojas ER, Yadavalli SS, Zhang L, Goulian M, Foster LJ, Huang KC, Hou YM. tRNA Methylation Is a Global Determinant of Bacterial Multi-drug Resistance. Cell Syst 2019; 8:302-314.e8. [PMID: 30981730 PMCID: PMC6483872 DOI: 10.1016/j.cels.2019.03.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 12/19/2018] [Accepted: 03/15/2019] [Indexed: 10/27/2022]
Abstract
Gram-negative bacteria are intrinsically resistant to drugs because of their double-membrane envelope structure that acts as a permeability barrier and as an anchor for efflux pumps. Antibiotics are blocked and expelled from cells and cannot reach high-enough intracellular concentrations to exert a therapeutic effect. Efforts to target one membrane protein at a time have been ineffective. Here, we show that m1G37-tRNA methylation determines the synthesis of a multitude of membrane proteins via its control of translation at proline codons near the start of open reading frames. Decreases in m1G37 levels in Escherichia coli and Salmonella impair membrane structure and sensitize these bacteria to multiple classes of antibiotics, rendering them incapable of developing resistance or persistence. Codon engineering of membrane-associated genes reduces their translational dependence on m1G37 and confers resistance. These findings highlight the potential of tRNA methylation in codon-specific translation to control the development of multi-drug resistance in Gram-negative bacteria.
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Affiliation(s)
- Isao Masuda
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Ryuma Matsubara
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Thomas Christian
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Enrique R Rojas
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Srujana S Yadavalli
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA
| | - Lisheng Zhang
- Department of Chemistry, University of Chicago, Chicago, IL 60637, USA
| | - Mark Goulian
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Leonard J Foster
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
| | - Ya-Ming Hou
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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14
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Park J, Kim H, Kim S, Lee D, Kim MS, Shin DH. Crystal structure of D-glycero-Β-D-manno-heptose-1-phosphate adenylyltransferase fromBurkholderia pseudomallei. Proteins 2017; 86:124-131. [DOI: 10.1002/prot.25398] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 10/02/2017] [Accepted: 10/04/2017] [Indexed: 12/17/2022]
Affiliation(s)
- Jimin Park
- College of Pharmacy; Ewha W. University; Seoul Republic of Korea
| | - Hyojin Kim
- College of Pharmacy; Ewha W. University; Seoul Republic of Korea
| | - Suwon Kim
- College of Pharmacy; Ewha W. University; Seoul Republic of Korea
| | - Daeun Lee
- College of Pharmacy; Ewha W. University; Seoul Republic of Korea
| | - Mi-Sun Kim
- College of Pharmacy; Ewha W. University; Seoul Republic of Korea
| | - Dong Hae Shin
- College of Pharmacy; Ewha W. University; Seoul Republic of Korea
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15
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General assay for enzymes in the heptose biosynthesis pathways using electrospray ionization mass spectrometry. Appl Microbiol Biotechnol 2017; 101:4521-4532. [DOI: 10.1007/s00253-017-8148-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 01/12/2017] [Accepted: 01/25/2017] [Indexed: 10/20/2022]
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16
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A Transposon Screen Identifies Genetic Determinants of Vibrio cholerae Resistance to High-Molecular-Weight Antibiotics. Antimicrob Agents Chemother 2016; 60:4757-63. [PMID: 27216069 DOI: 10.1128/aac.00576-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Accepted: 05/19/2016] [Indexed: 12/22/2022] Open
Abstract
Gram-negative bacteria are notoriously resistant to a variety of high-molecular-weight antibiotics due to the limited permeability of their outer membrane (OM). The basis of OM barrier function and the genetic factors required for its maintenance remain incompletely understood. Here, we employed transposon insertion sequencing to identify genes required for Vibrio cholerae resistance to vancomycin and bacitracin, antibiotics that are thought to be too large to efficiently penetrate the OM. The screen yielded several genes whose protein products are predicted to participate in processes important for OM barrier functions and for biofilm formation. In addition, we identified a novel factor, designated vigA (for vancomycin inhibits growth), that has not previously been characterized or linked to outer membrane function. The vigA open reading frame (ORF) codes for an inner membrane protein, and in its absence, cells became highly sensitive to glycopeptide antibiotics (vancomycin and ramoplanin) and bacitracin but not to other large antibiotics or detergents. In contrast to wild-type (WT) cells, the vigA mutant was stained with fluorescent vancomycin. These observations suggest that VigA specifically prevents the periplasmic accumulation of certain large antibiotics without exerting a general role in the maintenance of OM integrity. We also observed marked interspecies variability in the susceptibilities of Gram-negative pathogens to glycopeptides and bacitracin. Collectively, our findings suggest that the OM barrier is not absolute but rather depends on specific OM-antibiotic interactions.
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17
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Roy C, Alam M, Mandal S, Haldar PK, Bhattacharya S, Mukherjee T, Roy R, Rameez MJ, Misra AK, Chakraborty R, Nanda AK, Mukhopadhyay SK, Ghosh W. Global Association between Thermophilicity and Vancomycin Susceptibility in Bacteria. Front Microbiol 2016; 7:412. [PMID: 27065976 PMCID: PMC4814524 DOI: 10.3389/fmicb.2016.00412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 03/14/2016] [Indexed: 11/13/2022] Open
Abstract
Exploration of the aquatic microbiota of several circum-neutral (6.0-8.5 pH) mid-temperature (55-85°C) springs revealed rich diversities of phylogenetic relatives of mesophilic bacteria, which surpassed the diversity of the truly-thermophilic taxa. To gain insight into the potentially-thermophilic adaptations of the phylogenetic relatives of Gram-negative mesophilic bacteria detected in culture-independent investigations we attempted pure-culture isolation by supplementing the enrichment media with 50 μg ml(-1) vancomycin. Surprisingly, this Gram-positive-specific antibiotic eliminated the entire culturable-diversity of chemoorganotrophic and sulfur-chemolithotrophic bacteria present in the tested hot water inocula. Moreover, it also killed all the Gram-negative hot-spring isolates that were obtained in vancomycin-free media. Concurrent literature search for the description of Gram-negative thermophilic bacteria revealed that at least 16 of them were reportedly vancomycin-susceptible. While these data suggested that vancomycin-susceptibility could be a global trait of thermophilic bacteria (irrespective of their taxonomy, biogeography and Gram-character), MALDI Mass Spectroscopy of the peptidoglycans of a few Gram-negative thermophilic bacteria revealed that tandem alanines were present in the fourth and fifth positions of their muropeptide precursors (MPPs). Subsequent phylogenetic analyses revealed a close affinity between the D-alanine-D-alanine ligases (Ddl) of taxonomically-diverse Gram-negative thermophiles and the thermostable Ddl protein of Thermotoga maritima, which is well-known for its high specificity for alanine over other amino acids. The Ddl tree further illustrated a divergence between the homologs of Gram-negative thermophiles and mesophiles, which broadly coincided with vancomycin-susceptibility and vancomycin-resistance respectively. It was thus hypothesized that thermophilic Ddls have been evolutionarily selected to favor a D-ala-D-ala bonding. However, preference for D-ala-D-ala-terminated MPPs does not singlehandedly guarantee vancomycin susceptibility of thermophilic bacteria as the large and relatively-hydrophilic vancomycin molecule has to cross the outer membrane before it can inhibit peptidoglycan biosynthesis. Literature shows that many mesophilic Gram-negative bacteria also have D-ala-D-ala-terminated MPPs, but they still remain resistant to vancomycin due to the relative impermeability of their membranes. But the global vancomycin-susceptibility phenotype of thermophilic bacteria itself testifies that the drug crosses the membrane in all these cases. As a corollary, it seems quite likely that the outer membranes of thermophilic bacteria have some yet-unknown characteristic feature(s) that invariably ensures the entry of vancomycin.
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Affiliation(s)
- Chayan Roy
- Department of Microbiology, Bose Institute Kolkata, India
| | - Masrure Alam
- Department of Microbiology, Bose Institute Kolkata, India
| | | | | | | | | | - Rimi Roy
- Department of Microbiology, Bose Institute Kolkata, India
| | - Moidu J Rameez
- Department of Microbiology, Bose Institute Kolkata, India
| | - Anup K Misra
- Division of Molecular Medicine, Bose Institute Kolkata, India
| | | | - Ashish K Nanda
- Department of Chemistry, University of North Bengal Siliguri, India
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18
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Cold Stress Makes Escherichia coli Susceptible to Glycopeptide Antibiotics by Altering Outer Membrane Integrity. Cell Chem Biol 2016; 23:267-277. [DOI: 10.1016/j.chembiol.2015.12.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 12/02/2015] [Accepted: 12/22/2015] [Indexed: 11/20/2022]
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19
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Ebbensgaard A, Mordhorst H, Overgaard MT, Nielsen CG, Aarestrup FM, Hansen EB. Comparative Evaluation of the Antimicrobial Activity of Different Antimicrobial Peptides against a Range of Pathogenic Bacteria. PLoS One 2015; 10:e0144611. [PMID: 26656394 PMCID: PMC4684357 DOI: 10.1371/journal.pone.0144611] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 11/20/2015] [Indexed: 12/19/2022] Open
Abstract
ANALYSIS OF A SELECTED SET OF ANTIMICROBIAL PEPTIDES The rapid emergence of resistance to classical antibiotics has increased the interest in novel antimicrobial compounds. Antimicrobial peptides (AMPs) represent an attractive alternative to classical antibiotics and a number of different studies have reported antimicrobial activity data of various AMPs, but there is only limited comparative data available. The mode of action for many AMPs is largely unknown even though several models have suggested that the lipopolysaccharides (LPS) play a crucial role in the attraction and attachment of the AMP to the bacterial membrane in Gram-negative bacteria. We compared the potency of Cap18, Cap11, Cap11-1-18m2, Cecropin P1, Cecropin B, Bac2A, Bac2A-NH2, Sub5-NH2, Indolicidin, Melittin, Myxinidin, Myxinidin-NH2, Pyrrhocoricin, Apidaecin and Metalnikowin I towards Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Escherichia coli, Aeromonas salmonicida, Listeria monocytogenes, Campylobacter jejuni, Flavobacterium psychrophilum, Salmonella typhimurium and Yersinia ruckeri by minimal inhibitory concentration (MIC) determinations. Additional characteristics such as cytotoxicity, thermo and protease stability were measured and compared among the different peptides. Further, the antimicrobial activity of a selection of cationic AMPs was investigated in various E. coli LPS mutants. CAP18 SHOWS A HIGH BROAD SPECTRUM ANTIMICROBIAL ACTIVITY Of all the tested AMPs, Cap18 showed the most efficient antimicrobial activity, in particular against Gram-negative bacteria. In addition, Cap18 is highly thermostable and showed no cytotoxic effect in a hemolytic assay, measured at the concentration used. However, Cap18 is, as most of the tested AMPs, sensitive to proteolytic digestion in vitro. Thus, Cap18 is an excellent candidate for further development into practical use; however, modifications that should reduce the protease sensitivity would be needed. In addition, our findings from analyzing LPS mutant strains suggest that the core oligosaccharide of the LPS molecule is not essential for the antimicrobial activity of cationic AMPs, but in fact has a protective role against AMPs.
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Affiliation(s)
- Anna Ebbensgaard
- National Food Institute, Technical University of Denmark, Søltofts Plads, 2800 Kgs, Lyngby, Denmark
| | - Hanne Mordhorst
- National Food Institute, Technical University of Denmark, Søltofts Plads, 2800 Kgs, Lyngby, Denmark
| | - Michael Toft Overgaard
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220, Aalborg, Denmark
| | - Claus Gyrup Nielsen
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220, Aalborg, Denmark
| | - Frank Møller Aarestrup
- National Food Institute, Technical University of Denmark, Søltofts Plads, 2800 Kgs, Lyngby, Denmark
| | - Egon Bech Hansen
- National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, 2860, Søborg, Denmark
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20
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Small-molecule inhibitors of gram-negative lipoprotein trafficking discovered by phenotypic screening. J Bacteriol 2015; 197:1075-82. [PMID: 25583975 DOI: 10.1128/jb.02352-14] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
In Gram-negative bacteria, lipoproteins are transported to the outer membrane by the Lol system. In this process, lipoproteins are released from the inner membrane by the ABC transporter LolCDE and passed to LolA, a diffusible periplasmic molecular chaperone. Lipoproteins are then transferred to the outer membrane receptor protein, LolB, for insertion in the outer membrane. Here we describe the discovery and characterization of novel pyridineimidazole compounds that inhibit this process. Escherichia coli mutants resistant to the pyridineimidazoles show no cross-resistance to other classes of antibiotics and map to either the LolC or LolE protein of the LolCDE transporter complex. The pyridineimidazoles were shown to inhibit the LolA-dependent release of the lipoprotein Lpp from E. coli spheroplasts. These results combined with bacterial cytological profiling are consistent with LolCDE-mediated disruption of lipoprotein targeting to the outer membrane as the mode of action of these pyridineimidazoles. The pyridineimidazoles are the first reported inhibitors of the LolCDE complex, a target which has never been exploited for therapeutic intervention. These compounds open the door to further interrogation of the outer membrane lipoprotein transport pathway as a target for antimicrobial therapy.
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21
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Potent synergy and sustained bactericidal activity of a vancomycin-colistin combination versus multidrug-resistant strains of Acinetobacter baumannii. Antimicrob Agents Chemother 2010; 54:5316-22. [PMID: 20876375 DOI: 10.1128/aac.00922-10] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Multidrug-resistant Acinetobacter baumannii (MDRAB) presents an increasing challenge to health care. Although colistin has been used as a treatment of last resort, there is concern regarding its potential for toxicity and the emergence of resistance. The mechanism of action of colistin, however, raises the possibility of synergy with compounds that are normally inactive against Gram-negative organisms by virtue of the impermeability of the bacterial outer membrane. This study evaluated the effect of colistin combined with vancomycin on 5 previously characterized epidemic strains and 34 MDRAB clinical isolates by using time-kill assay, microdilution, and Etest methods. For all the isolates, significant synergy was demonstrated by at least one method, with reductions in the MIC of vancomycin from >256 μg/ml to ≤48 μg/ml for all strains after exposure to 0.5 μg/ml colistin. This raises the possibility of the clinical use of this combination for infections due to MDRAB, with the potential for doses lower than those currently used.
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Abstract
The emergence of mutations in nucleic acids is one of the major factors underlying evolution, providing the working material for natural selection. Most bacteria are haploid for the vast majority of their genes and, coupled with typically short generation times, this allows mutations to emerge and accumulate rapidly, and to effect significant phenotypic changes in what is perceived to be real-time. Not least among these phenotypic changes are those associated with antibiotic resistance. Mechanisms of horizontal gene spread among bacterial strains or species are often considered to be the main mediators of antibiotic resistance. However, mutational resistance has been invaluable in studies of bacterial genetics, and also has primary clinical importance in certain bacterial species, such as Mycobacterium tuberculosis and Helicobacter pylori, or when considering resistance to particular antibiotics, especially to synthetic agents such as fluoroquinolones and oxazolidinones. In addition, mutation is essential for the continued evolution of acquired resistance genes and has, e.g., given rise to over 100 variants of the TEM family of beta-lactamases. Hypermutator strains of bacteria, which have mutations in genes affecting DNA repair and replication fidelity, have elevated mutation rates. Mutational resistance emerges de novo more readily in these hypermutable strains, and they also provide a suitable host background for the evolution of acquired resistance genes in vitro. In the clinical setting, hypermutator strains of Pseudomonas aeruginosa have been isolated from the lungs of cystic fibrosis patients, but a more general role for hypermutators in the emergence of clinically relevant antibiotic resistance in a wider variety of bacterial pathogens has not yet been proven.
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Affiliation(s)
- N Woodford
- Antibiotic Resistance Monitoring and Reference Laboratory, Centre for Infections, Health Protection Agency, London, UK.
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23
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Loll PJ, Axelsen PH. The structural biology of molecular recognition by vancomycin. ANNUAL REVIEW OF BIOPHYSICS AND BIOMOLECULAR STRUCTURE 2001; 29:265-89. [PMID: 10940250 DOI: 10.1146/annurev.biophys.29.1.265] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Vancomycin is the archetype among naturally occurring compounds known as glycopeptide antibiotics. Because it is a vital therapeutic agent used world-wide for the treatment of infections with gram-positive bacteria, emerging bacterial resistance to vancomycin is a major public health threat. Recent investigations into the mechanisms of action of glycopeptide antibiotics are driven by a need to understand their detailed mechanism of action so that new agents can be developed to overcome resistance. These investigations have revealed that glycopeptide antibiotics exhibit a rich array of complex cooperative phenomena when they bind target ligands, making them valuable model systems for the study of molecular recognition.
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Affiliation(s)
- P J Loll
- Department of Pharmacology, Johnson Foundation for Molecular Biophysics, University of Pennsylvania School of Medicine, Philadelphia 19104-6084, USA.
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24
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Quesada AR, Cañedo A, Moreno MA, Fernández-Puentes JL. A microtitre plate-based assay for the screening of beta-lactams. Lett Appl Microbiol 1996; 22:303-6. [PMID: 8934791 DOI: 10.1111/j.1472-765x.1996.tb01166.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A simple, rapid, sensitive and automatizable method for the detection and quantification of bacterial cell wall inhibitors has been developed. The procedure is characterized by the use of a micro-organism hypersensitive to beta-lactam antibiotics that contains an inducible cytosolic beta-galactosidase; this enzyme is released when the micro-organism cell wall is disrupted by the antibiotic action, and then measured by the use of a chromogenic substrate. The present method allows the detection of beta-lactam traces in other non-beta-lactam antibiotics, and has been successfully applied in the detection of small amounts of beta-lactams in biological fluids such as milk and Actinomycetes fermentation broths. The easy automatization of this method makes it specially suitable for the screening of new antibiotics of natural origin.
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Affiliation(s)
- A R Quesada
- Departamento de Investigación, Antibióticos S.A., León, Spain
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25
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Rida S, Caillet J, Alix JH. Amplification of a novel gene, sanA, abolishes a vancomycin-sensitive defect in Escherichia coli. J Bacteriol 1996; 178:94-102. [PMID: 8550448 PMCID: PMC177625 DOI: 10.1128/jb.178.1.94-102.1996] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
We have isolated an Escherichia coli gene which, when overexpressed, is able to complement the permeability defects of a vancomycin-susceptible mutant. This gene, designated sanA, is located at min 47 of the E. coli chromosome and codes for a 20-kDa protein with a highly hydrophobic amino-terminal segment. A strain carrying a null mutation of the sanA gene, transferred to the E. coli chromosome by homologous recombination, is perfectly viable, but after two generations at high temperature (43 degrees C), the barrier function of its envelope towards vancomycin is defective.
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Affiliation(s)
- S Rida
- Institut de Biologie Physico-Chimique, Paris, France
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26
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Menninger JR, Coleman RA, Tsai LN. Erythromycin, lincosamides, peptidyl-tRNA dissociation, and ribosome editing. MOLECULAR & GENERAL GENETICS : MGG 1994; 243:225-33. [PMID: 8177219 DOI: 10.1007/bf00280320] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Inaccurate protein synthesis produces unstable beta-galactosidase, whose activity is rapidly lost at high temperature. Erythromycin, lincomycin, clindamycin, and celesticetin were shown to counteract the error-inducing effects of streptomycin on beta-galactosidase synthesized in the antibiotic-hypersensitive Escherichia coli strain DB-11 Met-. Newly synthesized beta-galactosidase was more easily inactivated by high temperatures when synthesized by bacteria partially starved for arginine, threonine, or methionine. Simultaneous treatment with erythromycin or lincomycin yielded beta-galactosidase that was inactivated by high temperatures less easily than during starvation alone, an effect attributed to stimulation of ribosome editing. When synthesized in the presence of canavanine, beta-galactosidase was inactivated by high temperature more easily but this effect could not be reversed by erythromycin. The first arginine in beta-galactosidase occurs at residue 13, so the effect of erythromycin during arginine starvation is probably to stimulate dissociation of erroneous peptidyl-tRNAs of at least that length. Correction of errors induced by methionine starvation is probably due to stimulation of dissociation of erroneous peptidyl-tRNAs bearing peptides at least 92 residues in length. All the effects of erythromycin or the tested lincosamides on protein synthesis are probably the result of stimulating the dissociation from ribosomes of peptidyl-tRNAs that are erroneous or short.
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Affiliation(s)
- J R Menninger
- Department of Biological Sciences, University of Iowa, Iowa City 52242-1324
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27
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Vaara M. Antibiotic-supersusceptible mutants of Escherichia coli and Salmonella typhimurium. Antimicrob Agents Chemother 1993; 37:2255-60. [PMID: 8285603 PMCID: PMC192375 DOI: 10.1128/aac.37.11.2255] [Citation(s) in RCA: 132] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Affiliation(s)
- M Vaara
- Department of Bacteriology and Immunology, University of Helsinki, Finland
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28
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Abstract
The outer membrane of gram-negative bacteria provides the cell with an effective permeability barrier against external noxious agents, including antibiotics, but is itself a target for antibacterial agents such as polycations and chelators. Both groups of agents weaken the molecular interactions of the lipopolysaccharide constituent of the outer membrane. Various polycations are able, at least under certain conditions, to bind to the anionic sites of lipopolysaccharide. Many of these disorganize and cross the outer membrane and render it permeable to drugs which permeate the intact membrane very poorly. These polycations include polymyxins and their derivatives, protamine, polymers of basic amino acids, compound 48/80, insect cecropins, reptilian magainins, various cationic leukocyte peptides (defensins, bactenecins, bactericidal/permeability-increasing protein, and others), aminoglycosides, and many more. However, the cationic character is not the sole determinant required for the permeabilizing activity, and therefore some of the agents are much more effective permeabilizers than others. They are useful tools in studies in which the poor permeability of the outer membrane poses problems. Some of them undoubtedly have a role as natural antibiotic substances, and they or their derivatives might have some potential as pharmaceutical agents in antibacterial therapy as well. Also, chelators (such as EDTA, nitrilotriacetic acid, and sodium hexametaphosphate), which disintegrate the outer membrane by removing Mg2+ and Ca2+, are effective and valuable permeabilizers.
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Affiliation(s)
- M Vaara
- Department of Bacteriology and Immunology, University of Helsinki, Finland
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29
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Abstract
The outer membrane of gram-negative bacteria provides the cell with an effective permeability barrier against external noxious agents, including antibiotics, but is itself a target for antibacterial agents such as polycations and chelators. Both groups of agents weaken the molecular interactions of the lipopolysaccharide constituent of the outer membrane. Various polycations are able, at least under certain conditions, to bind to the anionic sites of lipopolysaccharide. Many of these disorganize and cross the outer membrane and render it permeable to drugs which permeate the intact membrane very poorly. These polycations include polymyxins and their derivatives, protamine, polymers of basic amino acids, compound 48/80, insect cecropins, reptilian magainins, various cationic leukocyte peptides (defensins, bactenecins, bactericidal/permeability-increasing protein, and others), aminoglycosides, and many more. However, the cationic character is not the sole determinant required for the permeabilizing activity, and therefore some of the agents are much more effective permeabilizers than others. They are useful tools in studies in which the poor permeability of the outer membrane poses problems. Some of them undoubtedly have a role as natural antibiotic substances, and they or their derivatives might have some potential as pharmaceutical agents in antibacterial therapy as well. Also, chelators (such as EDTA, nitrilotriacetic acid, and sodium hexametaphosphate), which disintegrate the outer membrane by removing Mg2+ and Ca2+, are effective and valuable permeabilizers.
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Affiliation(s)
- M Vaara
- Department of Bacteriology and Immunology, University of Helsinki, Finland
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Vuorio R, Vaara M. The lipid A biosynthesis mutation lpxA2 of Escherichia coli results in drastic antibiotic supersusceptibility. Antimicrob Agents Chemother 1992; 36:826-9. [PMID: 1503445 PMCID: PMC189438 DOI: 10.1128/aac.36.4.826] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The conditionally lethal lpxA2 mutant of Escherichia coli, which lacks detectable UDP-N-acetylglucosamine acyltransferase activity and which produces greatly reduced amounts of lipid A after a shift to 42 degrees C (S. Galloway and C. R. H. Raetz, J. Biol. Chem. 265:6394-6402, 1990), was found to be, at conditions which promote normal growth, remarkably susceptible to a number of antibiotics. The MICs of hydrophobic antibiotics, such as rifampin, erythromycin, clindamycin, and fusidic acid, were 32- to greater than 128-fold lower for the lpxA2 strain than for the parent type strain, and those of the peptide antibiotics vancomycin and bacitracin were 32- and 256-fold lower, respectively. Futhermore, the lpxA2 strain was found to be sensitive to hypoosmotic conditions. Comparisons with the other characterized outer membrane permeability mutants, such as the heptose-deficient strains of E. coli and Salmonella typhimurium, the acrA and abs mutants of E. coli, and the ssc-1 and class SS-B mutants of S. typhimurium, indicated that the lpxA2 mutant had characteristically the most antibiotic-supersusceptible phenotype. These findings advocate the possible use of the lpxA2 strain as a tool in various fields of basic and applied bacterial research in which the impermeability of the outer membrane currently poses problems.
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Affiliation(s)
- R Vuorio
- Department of Bacteriology and Immunology, University of Helsinki, Finland
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Hirvas L, Vaara M. Effect of Ssc protein mutations on the outer membrane permeability barrier function inSalmonella typhimurium: a study usingsscmutant alleles made by site-directed mutagenesis. FEMS Microbiol Lett 1992. [DOI: 10.1111/j.1574-6968.1992.tb05168.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Qi SY, Sukupolvi S, O'Connor CD. Outer membrane permeability of Escherichia coli K12: isolation, cloning and mapping of suppressors of a defined antibiotic-hypersensitive mutant. MOLECULAR & GENERAL GENETICS : MGG 1991; 229:421-7. [PMID: 1944231 DOI: 10.1007/bf00267465] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We have previously described defined mutants of the TraT protein, an outer membrane lipoprotein specified by F-like plasmids, which sensitize Escherichia coli and Salmonella typhimurium to antibiotics that are normally excluded from the cell. In this paper, the isolation, characterization and molecular cloning of suppressors of one such mutant (pDOC40) is reported. The suppressors, which were isolated by selection for vancomycin-resistant revertants, also restored resistance to several hydrophobic antibiotics although there were no detectable changes in lipopolysaccharides (LPS), phospholipids or outer membrane proteins. Three suppressor loci, provisionally designated sip, for suppression of increased permeability, were cloned in cosmids and mapped by a novel approach involving random sequencing of cloned DNA to identify flanking genes with known map positions. Our results indicate that the sipB locus is located in the 11 min region (485-510 kb) whereas sipC and sipD both map to 82 min (3850-3885 kb). Additionally, the previously sequenced nlpA gene was also mapped to the 82 min region. The cloned suppressor loci were specific for the permeability phenotype caused by the mutant R6-5 TraT protein and had no effect on the permeability phenotype caused by a related TraT mutant of S. typhimurium.
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Affiliation(s)
- S Y Qi
- Department of Biochemistry, University of Southampton, UK
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Brisson-Noël A, Dutka-Malen S, Molinas C, Leclercq R, Courvalin P. Cloning and heterospecific expression of the resistance determinant vanA encoding high-level resistance to glycopeptides in Enterococcus faecium BM4147. Antimicrob Agents Chemother 1990; 34:924-7. [PMID: 2360831 PMCID: PMC171723 DOI: 10.1128/aac.34.5.924] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Fragments of plasmid pIP816, which confers high-level glycopeptide resistance in Enterococcus faecium BM4147, were cloned into a conjugative gram-negative-gram-positive shuttle vector. The resulting hybrids were transferred by conjugation from Escherichia coli to Enterococcus faecalis and Bacillus thuringiensis. A 4-kilobase EcoRI fragment from pIP816 was found to confer vancomycin resistance in these hosts but not in E. coli or Bacillus subtilis.
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Affiliation(s)
- A Brisson-Noël
- Unité des Agents Antibactériens, Unité Associée Centre National de la Recherche Scientifique 271, Institut Pasteur, Paris, France
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Shlaes DM, Binczewski B. Enterococcal resistance to vancomycin and related cyclic glycopeptide antibiotics. Eur J Clin Microbiol Infect Dis 1990; 9:106-10. [PMID: 2318215 DOI: 10.1007/bf01963634] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Enterococci belonging to various species resistant to vancomycin and related cyclic glycopeptide antibiotics have been isolated from hospitalized patients in France, the UK and the USA. All such strains examined display inducible synthesis of a membrane protein associated with resistance. The mechanism by which the membrane protein acts has not been definitively established, but it may block the access of the antibiotic to its peptidoglycan target. That the protein could be a bypass enzyme has not been ruled out. Transfer of glycopeptide resistance by conjugation to either Enterococcus faecium or Enterococcus faecalis and by transformation of Streptococcus sanguis Challis has been reported. The structural and regulatory genes encoding this resistance can be localized on plasmid and, apparently, chromosomal DNA. The plasmids encoding this resistance appear to differ from each other and have variable host ranges, but share at least some DNA sequence homology.
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Affiliation(s)
- D M Shlaes
- Infectious Diseases Section, Veterans Administration Medical Center, Cleveland, Ohio
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