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Kavanaugh LG, Dey D, Shafer WM, Conn GL. Structural and functional diversity of Resistance-Nodulation-Division (RND) efflux pump transporters with implications for antimicrobial resistance. Microbiol Mol Biol Rev 2024; 88:e0008923. [PMID: 39235227 PMCID: PMC11426026 DOI: 10.1128/mmbr.00089-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2024] Open
Abstract
SUMMARYThe discovery of bacterial efflux pumps significantly advanced our understanding of how bacteria can resist cytotoxic compounds that they encounter. Within the structurally and functionally distinct families of efflux pumps, those of the Resistance-Nodulation-Division (RND) superfamily are noteworthy for their ability to reduce the intracellular concentration of structurally diverse antimicrobials. RND systems are possessed by many Gram-negative bacteria, including those causing serious human disease, and frequently contribute to resistance to multiple antibiotics. Herein, we review the current literature on the structure-function relationships of representative transporter proteins of tripartite RND efflux pumps of clinically important pathogens. We emphasize their contribution to bacterial resistance to clinically used antibiotics, host defense antimicrobials and other biocides, as well as highlighting structural similarities and differences among efflux transporters that help bacteria survive in the face of antimicrobials. Furthermore, we discuss technical advances that have facilitated and advanced efflux pump research and suggest future areas of investigation that will advance antimicrobial development efforts.
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Affiliation(s)
- Logan G Kavanaugh
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
- Graduate Program in Microbiology and Molecular Genetics, Emory University, Atlanta, Georgia, USA
| | - Debayan Dey
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
| | - William M Shafer
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
- Laboratories of Microbial Pathogenesis, VA Medical Research Service, Veterans Affairs Medical Center, Decatur, Georgia, USA
- Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Graeme L Conn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
- Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
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Delaleau M, Figueroa-Bossi N, Do TD, Kerboriou P, Eveno E, Bossi L, Boudvillain M. Rho-dependent transcriptional switches regulate the bacterial response to cold shock. Mol Cell 2024; 84:3482-3496.e7. [PMID: 39178862 DOI: 10.1016/j.molcel.2024.07.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 06/17/2024] [Accepted: 07/31/2024] [Indexed: 08/26/2024]
Abstract
Binding of the bacterial Rho helicase to nascent transcripts triggers Rho-dependent transcription termination (RDTT) in response to cellular signals that modulate mRNA structure and accessibility of Rho utilization (Rut) sites. Despite the impact of temperature on RNA structure, RDTT was never linked to the bacterial response to temperature shifts. We show that Rho is a central player in the cold-shock response (CSR), challenging the current view that CSR is primarily a posttranscriptional program. We identify Rut sites in 5'-untranslated regions of key CSR genes/operons (cspA, cspB, cspG, and nsrR-rnr-yjfHI) that trigger premature RDTT at 37°C but not at 15°C. High concentrations of RNA chaperone CspA or nucleotide changes in the cspA mRNA leader reduce RDTT efficiency, revealing how RNA restructuring directs Rho to activate CSR genes during the cold shock and to silence them during cold acclimation. These findings establish a paradigm for how RNA thermosensors can modulate gene expression.
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Affiliation(s)
- Mildred Delaleau
- Centre de Biophysique Moléculaire, CNRS UPR4301, Affiliated with Université d'Orléans, rue Charles Sadron, 45071 Orléans Cedex 2, France
| | - Nara Figueroa-Bossi
- Université Paris-Saclay, CEA, CNRS, Institut de Biologie Intégrative de la Cellule (I2BC), 91190 Gif-sur-Yvette, France
| | - Thuy Duong Do
- Centre de Biophysique Moléculaire, CNRS UPR4301, Affiliated with Université d'Orléans, rue Charles Sadron, 45071 Orléans Cedex 2, France; ED 549, Sciences Biologiques & Chimie du Vivant, Université d'Orléans, Orléans, France
| | - Patricia Kerboriou
- Université Paris-Saclay, CEA, CNRS, Institut de Biologie Intégrative de la Cellule (I2BC), 91190 Gif-sur-Yvette, France
| | - Eric Eveno
- Centre de Biophysique Moléculaire, CNRS UPR4301, Affiliated with Université d'Orléans, rue Charles Sadron, 45071 Orléans Cedex 2, France
| | - Lionello Bossi
- Université Paris-Saclay, CEA, CNRS, Institut de Biologie Intégrative de la Cellule (I2BC), 91190 Gif-sur-Yvette, France
| | - Marc Boudvillain
- Centre de Biophysique Moléculaire, CNRS UPR4301, Affiliated with Université d'Orléans, rue Charles Sadron, 45071 Orléans Cedex 2, France; ED 549, Sciences Biologiques & Chimie du Vivant, Université d'Orléans, Orléans, France.
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Ikujuni AP, Dhar R, Cordova A, Bowman AM, Noga S, Slusky JSG. Discovery and Characterization of Two Folded Intermediates for Outer Membrane Protein TolC Biogenesis. J Mol Biol 2024; 436:168652. [PMID: 38871177 PMCID: PMC11297670 DOI: 10.1016/j.jmb.2024.168652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 05/12/2024] [Accepted: 06/06/2024] [Indexed: 06/15/2024]
Abstract
TolC is the outer membrane protein responsible for antibiotic efflux in E. coli. Compared to other outer membrane proteins it has an unusual fold and has been shown to fold independently of commonly used periplasmic chaperones, SurA and Skp. Here we find that the assembly of TolC involves the formation of two folded intermediates using circular dichroism, gel electrophoresis, site-specific disulfide bond formation and radioactive labeling. First the TolC monomer folds, and then TolC assembles into a trimer both in detergent-free buffer and in the presence of detergent micelles. We find that a TolC trimer also forms in the periplasm and is present in the periplasm before it inserts in the outer membrane. The monomeric and trimeric folding intermediates may be used in the future to develop a new approach to antibiotic efflux pump inhibition by targeting the assembly pathway of TolC.
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Affiliation(s)
- Ayotunde Paul Ikujuni
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Ave, Lawrence, KS 66045, United States
| | - Rik Dhar
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Ave, Lawrence, KS 66045, United States
| | - Andres Cordova
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Ave, Lawrence, KS 66045, United States
| | - Alexander M Bowman
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Ave, Lawrence, KS 66045, United States
| | - Sarah Noga
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Ave, Lawrence, KS 66045, United States
| | - Joanna S G Slusky
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Ave, Lawrence, KS 66045, United States; Computational Biology Program, The University of Kansas, 2030 Becker Dr., Lawrence, KS 66045-7534, United States.
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da Rosa EEB, Kremer FS. The mobilome landscape of biocide-resistance in Brazilian ESKAPE isolates. Braz J Microbiol 2024:10.1007/s42770-024-01450-7. [PMID: 39028534 DOI: 10.1007/s42770-024-01450-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Accepted: 07/03/2024] [Indexed: 07/20/2024] Open
Abstract
The increasing frequency of antibiotic-resistant bacteria is a constant threat to global human health. Therefore, the pathogens of the ESKAPE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, and Enterobacter spp.) are among the most relevant causes of hospital infections responsible for millions of deaths every year. However, little has been explored about the danger of microorganisms resistant to biocides such as antiseptics and disinfectants. Widely used in domestic, industrial, and hospital environments, these substances reach the environment and can cause selective pressure for resistance genes and induce cross-resistance to antibiotics, further aggravating the problem. Therefore, it is necessary to use innovative and efficient strategies to monitor the spread of genes related to resistance to biocides. Whole genome sequencing and bioinformatics analysis aiming to search for sequences encoding resistance mechanisms are essential to help monitor and combat these pathogens. Thus, this work describes the construction of a bioinformatics tool that integrates different databases to identify gene sequences that may confer some resistance advantage about biocides. Furthermore, the tool analyzed all the genomes of Brazilian ESKAPE isolates deposited at NCBI and found a series of different genes related to resistance to benzalkonium chloride, chlorhexidine, and triclosan, which were the focus of this work. As a result, the presence of resistance genes was identified in different types of biological samples, environments, and hosts. Regarding mobile genetic elements (MGEs), around 52% of isolates containing genes related to resistance to these compounds had their genes identified in plasmids, and 48.7% in prophages. These data show that resistance to biocides can be a silent, underestimated danger spreading across different environments and, therefore, requires greater attention.
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Affiliation(s)
- Elias Eduardo Barbosa da Rosa
- Laboratório de Bioinformática (Omixlab), Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Rio Grande Do Sul, Brazil
| | - Frederico Schmitt Kremer
- Laboratório de Bioinformática (Omixlab), Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Rio Grande Do Sul, Brazil.
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Li Y, Guo Y, Niu F, Gao H, Wang Q, Xu M. Regulation of oxidative stress response and antioxidant modification in Corynebacterium glutamicum. World J Microbiol Biotechnol 2024; 40:267. [PMID: 39004689 DOI: 10.1007/s11274-024-04066-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2024] [Accepted: 06/27/2024] [Indexed: 07/16/2024]
Abstract
As an efficient and safe industrial bacterium, Corynebacterium glutamicum has extensive application in amino acid production. However, it often faces oxidative stress induced by reactive oxygen species (ROS), leading to diminished production efficiency. To enhance the robustness of C. glutamicum, numerous studies have focused on elucidating its regulatory mechanisms under various stress conditions such as heat, acid, and sulfur stress. However, a comprehensive review of its defense mechanisms against oxidative stress is needed. This review offers an in-depth overview of the mechanisms C. glutamicum employs to manage oxidative stress. It covers both enzymatic and non-enzymatic systems, including antioxidant enzymes, regulatory protein families, sigma factors involved in transcription, and physiological redox reduction pathways. This review provides insights for advancing research on the antioxidant mechanisms of C. glutamicum and sheds light on its potential applications in industrial production.
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Affiliation(s)
- Yueshu Li
- The Key Laboratory of Industrial Biotechnology, School of Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Yuanyi Guo
- The Key Laboratory of Industrial Biotechnology, School of Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Fangyuan Niu
- The Key Laboratory of Industrial Biotechnology, School of Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Hui Gao
- The Key Laboratory of Industrial Biotechnology, School of Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Qing Wang
- The Key Laboratory of Industrial Biotechnology, School of Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Meijuan Xu
- The Key Laboratory of Industrial Biotechnology, School of Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China.
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Laborda P, Molin S, Johansen HK, Martínez JL, Hernando-Amado S. Role of bacterial multidrug efflux pumps during infection. World J Microbiol Biotechnol 2024; 40:226. [PMID: 38822187 DOI: 10.1007/s11274-024-04042-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Accepted: 05/29/2024] [Indexed: 06/02/2024]
Abstract
Multidrug efflux pumps are protein complexes located in the cell envelope that enable bacteria to expel, not only antibiotics, but also a wide array of molecules relevant for infection. Hence, they are important players in microbial pathogenesis. On the one hand, efflux pumps can extrude exogenous compounds, including host-produced antimicrobial molecules. Through this extrusion, pathogens can resist antimicrobial agents and evade host defenses. On the other hand, efflux pumps also have a role in the extrusion of endogenous compounds, such as bacterial intercommunication signaling molecules, virulence factors or metabolites. Therefore, efflux pumps are involved in the modulation of bacterial behavior and virulence, as well as in the maintenance of the bacterial homeostasis under different stresses found within the host. This review delves into the multifaceted roles that efflux pumps have, shedding light on their impact on bacterial virulence and their contribution to bacterial infection. These observations suggest that strategies targeting bacterial efflux pumps could both reinvigorate the efficacy of existing antibiotics and modulate the bacterial pathogenicity to the host. Thus, a comprehensive understanding of bacterial efflux pumps can be pivotal for the development of new effective strategies for the management of infectious diseases.
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Affiliation(s)
- Pablo Laborda
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, 9301, Denmark.
| | - Søren Molin
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Helle Krogh Johansen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, 9301, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Numata Y, Kikuchi Y, Sato T, Okamoto-Shibayama K, Ando Y, Miyai-Murai Y, Kokubu E, Ishihara K. Novel transcriptional regulator OxtR1 regulates potential ferrodoxin in response to oxygen stress in Treponema denticola. Anaerobe 2024; 87:102852. [PMID: 38614291 DOI: 10.1016/j.anaerobe.2024.102852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 02/26/2024] [Accepted: 04/08/2024] [Indexed: 04/15/2024]
Abstract
OBJECTIVE Treponema denticola has been strongly implicated in the pathogenesis of chronic periodontitis. Previously, we reported that the potential transcriptional regulator TDE_0259 (oxtR1) is upregulated in the bacteriocin ABC transporter gene-deficient mutant. OxtR1 may regulate genes to adapt to environmental conditions during colonization; however, the exact role of the gene in T. denticola has not been reported. Therefore, we investigated its function using an oxtR1-deficient mutant. METHODS The growth rates of the wild-type and oxtR1 mutant were monitored under anaerobic conditions; their antibacterial agent susceptibility and gene expression were assessed using a liquid dilution assay and DNA microarray, respectively. An electrophoretic mobility shift assay was performed to investigate the binding of OxtR1 to promoter regions. RESULTS The growth rate of the bacterium was accelerated by the inactivation of oxtR1, and the mutant exhibited an increased minimum inhibitory concentration against ofloxacin. We observed a relative increase in the expression of genes associated with potential ferrodoxin (TDE_0260), flavodoxin, ABC transporters, heat-shock proteins, DNA helicase, iron compounds, and lipoproteins in the mutant. OxtR1 expression increased upon oxygen exposure, and oxtR1 complementation suppressed the expression of potential ferrodoxin. Our findings also suggested that OxtR1 binds to a potential promoter region of the TDE_0259-260 operon. Moreover, the mutant showed a marginal yet significantly faster growth rate than the wild-type strain under H2O2 exposure. CONCLUSION The oxygen-sensing regulator OxtR1 plays a role in regulating the expression of a potential ferrodoxin, which may contribute to the response of T. denticola to oxygen-induced stress.
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Affiliation(s)
- Yumi Numata
- Department of Crown and Bridge Prosthodontics, Tokyo Dental College, 2-9-18 Kanda-Misakicho, Chiyoda-ku, Tokyo 101-0061, Japan
| | - Yuichiro Kikuchi
- Department of Microbiology, Tokyo Dental College, 2-1-14 Kanda-Misakicho, Chiyoda-ku, Tokyo 101-0061, Japan; Oral Health Science Center, Tokyo Dental College, 2-9-18 Kanda-Misakicho Chiyoda-ku, Tokyo 101-0061, Japan
| | - Toru Sato
- Department of Crown and Bridge Prosthodontics, Tokyo Dental College, 2-9-18 Kanda-Misakicho, Chiyoda-ku, Tokyo 101-0061, Japan
| | - Kazuko Okamoto-Shibayama
- Department of Microbiology, Tokyo Dental College, 2-1-14 Kanda-Misakicho, Chiyoda-ku, Tokyo 101-0061, Japan; Oral Health Science Center, Tokyo Dental College, 2-9-18 Kanda-Misakicho Chiyoda-ku, Tokyo 101-0061, Japan
| | - Yutaro Ando
- Department of Microbiology, Tokyo Dental College, 2-1-14 Kanda-Misakicho, Chiyoda-ku, Tokyo 101-0061, Japan; Oral Health Science Center, Tokyo Dental College, 2-9-18 Kanda-Misakicho Chiyoda-ku, Tokyo 101-0061, Japan
| | - Yuri Miyai-Murai
- Department of Crown and Bridge Prosthodontics, Tokyo Dental College, 2-9-18 Kanda-Misakicho, Chiyoda-ku, Tokyo 101-0061, Japan
| | - Eitoyo Kokubu
- Department of Microbiology, Tokyo Dental College, 2-1-14 Kanda-Misakicho, Chiyoda-ku, Tokyo 101-0061, Japan; Oral Health Science Center, Tokyo Dental College, 2-9-18 Kanda-Misakicho Chiyoda-ku, Tokyo 101-0061, Japan
| | - Kazuyuki Ishihara
- Department of Microbiology, Tokyo Dental College, 2-1-14 Kanda-Misakicho, Chiyoda-ku, Tokyo 101-0061, Japan; Oral Health Science Center, Tokyo Dental College, 2-9-18 Kanda-Misakicho Chiyoda-ku, Tokyo 101-0061, Japan.
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Rihacek M, Kuthanova M, Splichal Z, Adam V, Hrazdilova K, Vesely R, Zurek L, Cihalova K. Escherichia coli from Human Wounds: Analysis of Resistance to β-Lactams and Expression of RND Efflux Pumps. Infect Drug Resist 2023; 16:7365-7375. [PMID: 38050628 PMCID: PMC10693772 DOI: 10.2147/idr.s435622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 11/04/2023] [Indexed: 12/06/2023] Open
Abstract
Purpose Resistance of pathogenic strains of Escherichia coli to β-lactams, particularly to ampicillin, is on the rise and it is attributed to intrinsic and acquired mechanisms. One important factor contributing to resistance, together with primarily resistance mechanisms, is a mutation and/or an over-expression of the intrinsic efflux pumps in the resistance-nodulation-division (RND) superfamily. Among these efflux pumps, AcrA, AcrB, TolC, and AcrD play an important role in antimicrobial co-resistance, including resistance to β-lactams. Materials and Methods Twelve E. coli isolates obtained from patients' wounds and the control strain of E. coli ATCC 25922 were analyzed. The phenotypic resistance of these isolates to selected β-lactams was assessed by determination of the minimal inhibitory concentration. Additionally, the prevalence of β-lactamase genes (blaTEM, blaCTX-M, blaSHV, and blaAmpC) was screened by PCR. Real-time qPCR was used to determine the expression of the selected efflux pumps acrA, acrB, tolC, and acrD and the repressor acrR after the exposure of E. coli to ampicillin. Results Phenotypic resistance to β-lactams was detected in seven isolates, mainly to ampicillin and piperacillin. This was corroborated by the presence of at least one acquired bla gene in each of these isolates. Although E. coli strains varied in the expression of RND-family efflux pumps after the ampicillin exposure, their gene expression indicated that these pumps did not play a major role in the phenotypic resistance to ampicillin. Conclusion Each E. coli isolate displayed unique characteristics, differing in minimum inhibitory concentration (MIC) values, prevalence of acquired blaTEM and blaCTX-M genes, and expression of the RND-family pumps. This together demonstrates that these clinical isolates employed distinct intrinsic or acquired resistance pathways for their defense against ampicillin. The prevalence and spread of ampicillin resistant E. coli has to be monitored and the search for ampicillin alternatives is needed.
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Affiliation(s)
- Martin Rihacek
- Department of Chemistry and Biochemistry, Mendel University in Brno, Brno, Czech Republic
| | - Michaela Kuthanova
- Department of Chemistry and Biochemistry, Mendel University in Brno, Brno, Czech Republic
| | - Zbynek Splichal
- Department of Chemistry and Biochemistry, Mendel University in Brno, Brno, Czech Republic
| | - Vojtech Adam
- Department of Chemistry and Biochemistry, Mendel University in Brno, Brno, Czech Republic
| | - Kristyna Hrazdilova
- Department of Chemistry and Biochemistry, Mendel University in Brno, Brno, Czech Republic
| | - Radek Vesely
- Department of Traumatology at the Medical Faculty, Masaryk University and Trauma Hospital Brno, Brno, Czech Republic
- Department of Traumatology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Ludek Zurek
- Department of Chemistry and Biochemistry, Mendel University in Brno, Brno, Czech Republic
| | - Kristyna Cihalova
- Department of Chemistry and Biochemistry, Mendel University in Brno, Brno, Czech Republic
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Zhang SP, Ye YP, Hou J, Ye ZR, Wang ZS, Yu XQ, Guo DD, Wang Y, He YX. Antitoxin MqsA decreases antibiotic susceptibility through the global regulator AgtR in Pseudomonas fluorescens. Antimicrob Agents Chemother 2023; 67:e0081223. [PMID: 37877694 PMCID: PMC10649091 DOI: 10.1128/aac.00812-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/31/2023] [Indexed: 10/26/2023] Open
Abstract
Type II toxin-antitoxin systems are highly prevalent in bacterial genomes and play crucial roles in the general stress response. Previously, we demonstrated that the type II antitoxin PfMqsA regulates biofilm formation through the global regulator AgtR in Pseudomonas fluorescens. Here, we found that both the C-terminal DNA-binding domain of PfMqsA and AgtR are involved in bacterial antibiotic susceptibility. Electrophoretic mobility shift assay (EMSA) analyses revealed that AgtR, rather than PfMqsA, binds to the intergenic region of emhABC-emhR, in which emhABC encodes an resistance-nodulation-cell division efflux pump and emhR encodes a repressor. Through quantitative real-time reverse-transcription PCR and EMSA analysis, we showed that AgtR directly activates the expression of the emhR by binding to the DNA motif [5´-CTAAGAAATATACTTAC-3´], leading to repression of the emhABC. Furthermore, we demonstrated that PfMqsA modulates the expression of EmhABC and EmhR. These findings enhance our understanding of the mechanism by which antitoxin PfMqsA contributes to antibiotic susceptibility.
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Affiliation(s)
- Si-Ping Zhang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Yi-Ping Ye
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Jun Hou
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Zi-Rui Ye
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Zhi-Song Wang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Xiao-Quan Yu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Ding-Ding Guo
- School of Pharmacy, Lanzhou University, Lanzhou, Gansu, China
| | - Yong Wang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Yong-Xing He
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
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Deneka M, Ostash I, Yalamanchili S, Bennett CS, Ostash B. Insights into the Biological Properties of Ligands and Identity of Operator Site for LanK Protein Involved in Landomycin Production. Curr Microbiol 2023; 81:5. [PMID: 37950074 DOI: 10.1007/s00284-023-03528-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 10/17/2023] [Indexed: 11/12/2023]
Abstract
LanK is a TetR type regulatory protein that coordinates the late steps of the biosynthesis of the landomycin family of antitumor angucyclic polyketides and their export from the cells of Streptomyces cyanogenus S136. We recently described the structure of LanK and showed that it is the carbohydrate portion of the landomycins that is responsible for abrogating the repressing effect of LanK on landomycin production and export. The effect has been established in a series of in vitro tests using synthetic analogs of the landomycin carbohydrate chains. Whether such synthetic compounds would function as effector molecules for LanK under in vivo conditions remained unknown. Furthermore, the location and identity of LanK operator sites within the lanK-lanJ intergenic region (lanKJp) was unknown. Here we report that methoxyphenyl analogs of tri- and hexasaccharide chains of landomycins cannot function as LanK ligands when applied externally to the reporter strain. The lability of these compounds to cellular media and/or their poor penetration into the cells could explain our observations. The LanK operator site has been mapped to a 14-bp region of lanKJp that includes a plausible -35 site upstream of the lanK start codon in a series of electrophoretic DNA mobility shift assays. This opens the door to studies of the DNA-LanK interaction at a single nucleotide resolution level.
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Affiliation(s)
- Maksym Deneka
- Department of Genetics and Biotechnology, Ivan Franko National University of Lviv, 4 Hrushevskoho St, Lviv, 79005, Ukraine
| | - Iryna Ostash
- Department of Genetics and Biotechnology, Ivan Franko National University of Lviv, 4 Hrushevskoho St, Lviv, 79005, Ukraine
| | | | - Clay S Bennett
- Department of Chemistry, Tufts University, 62 Talbot Ave, Medford, MA, 02155, USA
| | - Bohdan Ostash
- Department of Genetics and Biotechnology, Ivan Franko National University of Lviv, 4 Hrushevskoho St, Lviv, 79005, Ukraine.
- Department of Genetics and Biotechnology, Ivan Franko National University of Lviv, 4 Hrushevskoho St.,Rm 102, Lviv, 79005, Ukraine.
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11
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Ding Y, Hao J, Xiao W, Ye C, Xiao X, Jian C, Tang M, Li G, Liu J, Zeng Z. Role of efflux pumps, their inhibitors, and regulators in colistin resistance. Front Microbiol 2023; 14:1207441. [PMID: 37601369 PMCID: PMC10436536 DOI: 10.3389/fmicb.2023.1207441] [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: 04/17/2023] [Accepted: 07/13/2023] [Indexed: 08/22/2023] Open
Abstract
Colistin is highly promising against multidrug-resistant and extensively drug-resistant bacteria clinically. Bacteria are resistant to colistin mainly through mcr and chromosome-mediated lipopolysaccharide (LPS) synthesis-related locus variation. However, the current understanding cannot fully explain the resistance mechanism in mcr-negative colistin-resistant strains. Significantly, the contribution of efflux pumps to colistin resistance remains to be clarified. This review aims to discuss the contribution of efflux pumps and their related transcriptional regulators to colistin resistance in various bacteria and the reversal effect of efflux pump inhibitors on colistin resistance. Previous studies suggested a complex regulatory relationship between the efflux pumps and their transcriptional regulators and LPS synthesis, transport, and modification. Carbonyl cyanide 3-chlorophenylhydrazone (CCCP), 1-(1-naphthylmethyl)-piperazine (NMP), and Phe-Arg-β-naphthylamide (PAβN) all achieved the reversal of colistin resistance, highlighting the role of efflux pumps in colistin resistance and their potential for adjuvant development. The contribution of the efflux pumps to colistin resistance might also be related to specific genetic backgrounds. They can participate in colistin tolerance and heterogeneous resistance to affect the treatment efficacy of colistin. These findings help understand the development of resistance in mcr-negative colistin-resistant strains.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Jinbo Liu
- Department of Laboratory Medicine, the Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Zhangrui Zeng
- Department of Laboratory Medicine, the Affiliated Hospital of Southwest Medical University, Luzhou, China
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12
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Yamasaki S, Zwama M, Yoneda T, Hayashi-Nishino M, Nishino K. Drug resistance and physiological roles of RND multidrug efflux pumps in Salmonella enterica, Escherichia coli and Pseudomonas aeruginosa. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001322. [PMID: 37319001 PMCID: PMC10333786 DOI: 10.1099/mic.0.001322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 03/18/2023] [Indexed: 06/17/2023]
Abstract
Drug efflux pumps transport antimicrobial agents out of bacteria, thereby reducing the intracellular antimicrobial concentration, which is associated with intrinsic and acquired bacterial resistance to these antimicrobials. As genome analysis has advanced, many drug efflux pump genes have been detected in the genomes of bacterial species. In addition to drug resistance, these pumps are involved in various essential physiological functions, such as bacterial adaptation to hostile environments, toxin and metabolite efflux, biofilm formation and quorum sensing. In Gram-negative bacteria, efflux pumps in the resistance–nodulation–division (RND) superfamily play a clinically important role. In this review, we focus on Gram-negative bacteria, including Salmonella enterica , Escherichia coli and Pseudomonas aeruginosa , and discuss the role of RND efflux pumps in drug resistance and physiological functions.
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Affiliation(s)
- Seiji Yamasaki
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
- Institute for Advanced Co-Creation Studies, Osaka University, 1-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Martijn Zwama
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - Tomohiro Yoneda
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Mitsuko Hayashi-Nishino
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Kunihiko Nishino
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
- Center for Infectious Disease Education and Research, 2-8 Yamadaoka, Osaka University, Suita, Osaka 565-0871, Japan
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13
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Sampath V. Use of a Role-Playing Activity To Increase Student Understanding of Bacterial Gene Regulation. JOURNAL OF MICROBIOLOGY & BIOLOGY EDUCATION 2023; 24:00006-23. [PMID: 37089225 PMCID: PMC10117148 DOI: 10.1128/jmbe.00006-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 03/02/2023] [Indexed: 05/03/2023]
Abstract
Undergraduate students often struggle to understand the basics of bacterial gene regulation, a key concept in microbiology. They find it hard to visualize the architecture of a bacterial operon or how the gene, RNA, and protein components interact with each other to regulate the operon. To better visualize the molecular interactions, students engaged in a role-playing exercise on bacterial gene regulation in the classroom. Before beginning the activity, they received a shortened, traditional lecture on the architecture and function of the lac operon under "on" and "off" conditions. Students chose one or more placards detailing a molecular role (such as promoter, repressor, RNA polymerase, gene X, gene Y, etc.). Upon receiving instructor prompts, they assembled in linear order to mimic correct genomic locations of genes and regulatory elements on the operon. When given a prompt for "operon on" or "operon off" condition, students identified all the necessary components (roles) for that condition, assembled in the correct order, and then moved through the assembled operon to mimic what happens inside the cell under that condition. Students were tested before and after the activity using a set of eight multiple-choice questions. Students showed significant gains in their ability to answer these questions correctly immediately after the activity. More importantly, the improved understanding was also reflected in a high median score on summative assessments given a few weeks after the completion of the activity. This activity can also be readily adapted to online or a hybrid mode of teaching to benefit larger student populations.
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Affiliation(s)
- Vinaya Sampath
- Department of Diagnostic Health Professions, Long Island University-Post, Brookville, New York, USA
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14
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Hernando-Amado S, Laborda P, Martínez JL. Tackling antibiotic resistance by inducing transient and robust collateral sensitivity. Nat Commun 2023; 14:1723. [PMID: 36997518 PMCID: PMC10063638 DOI: 10.1038/s41467-023-37357-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 03/13/2023] [Indexed: 04/03/2023] Open
Abstract
Collateral sensitivity (CS) is an evolutionary trade-off traditionally linked to the mutational acquisition of antibiotic resistance (AR). However, AR can be temporally induced, and the possibility that this causes transient, non-inherited CS, has not been addressed. Mutational acquisition of ciprofloxacin resistance leads to robust CS to tobramycin in pre-existing antibiotic-resistant mutants of Pseudomonas aeruginosa. Further, the strength of this phenotype is higher when nfxB mutants, over-producing the efflux pump MexCD-OprJ, are selected. Here, we induce transient nfxB-mediated ciprofloxacin resistance by using the antiseptic dequalinium chloride. Notably, non-inherited induction of AR renders transient tobramycin CS in the analyzed antibiotic-resistant mutants and clinical isolates, including tobramycin-resistant isolates. Further, by combining tobramycin with dequalinium chloride we drive these strains to extinction. Our results support that transient CS could allow the design of new evolutionary strategies to tackle antibiotic-resistant infections, avoiding the acquisition of AR mutations on which inherited CS depends.
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Affiliation(s)
| | - Pablo Laborda
- Centro Nacional de Biotecnología, CSIC, 28049, Madrid, Spain
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark
- Department of Clinical Microbiology 9301, Rigshospitalet, 2100, Copenhagen, Denmark
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15
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Chauviat A, Meyer T, Favre-Bonté S. Versatility of Stenotrophomonas maltophilia: Ecological roles of RND efflux pumps. Heliyon 2023; 9:e14639. [PMID: 37089375 PMCID: PMC10113797 DOI: 10.1016/j.heliyon.2023.e14639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/13/2023] [Accepted: 03/14/2023] [Indexed: 03/30/2023] Open
Abstract
S. maltophilia is a widely distributed bacterium found in natural, anthropized and clinical environments. The genome of this opportunistic pathogen of environmental origin includes a large number of genes encoding RND efflux pumps independently of the clinical or environmental origin of the strains. These pumps have been historically associated with the uptake of antibiotics and clinically relevant molecules because they confer resistance to many antibiotics. However, considering the environmental origin of S. maltophilia, the ecological role of these pumps needs to be clarified. RND efflux systems are highly conserved within bacteria and encountered both in pathogenic and non-pathogenic species. Moreover, their evolutionary origin, conservation and multiple copies in bacterial genomes suggest a primordial role in cellular functions and environmental adaptation. This review is aimed at elucidating the ecological role of S. maltophilia RND efflux pumps in the environmental context and providing an exhaustive description of the environmental niches of S. maltophilia. By looking at the substrates and functions of the pumps, we propose different involvements and roles according to the adaptation of the bacterium to various niches. We highlight that i°) regulatory mechanisms and inducer molecules help to understand the conditions leading to their expression, and ii°) association and functional redundancy of RND pumps and other efflux systems demonstrate their complex role within S. maltophilia cells. These observations emphasize that RND efflux pumps play a role in the versatility of S. maltophilia.
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Yadav H, Mahalvar A, Pradhan M, Yadav K, Kumar Sahu K, Yadav R. Exploring the potential of phytochemicals and nanomaterial: a boon to antimicrobial treatment. MEDICINE IN DRUG DISCOVERY 2023. [DOI: 10.1016/j.medidd.2023.100151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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17
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Chetri S. The culmination of multidrug-resistant efflux pumps vs. meager antibiotic arsenal era: Urgent need for an improved new generation of EPIs. Front Microbiol 2023; 14:1149418. [PMID: 37138605 PMCID: PMC10149990 DOI: 10.3389/fmicb.2023.1149418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 03/13/2023] [Indexed: 05/05/2023] Open
Abstract
Efflux pumps function as an advanced defense system against antimicrobials by reducing the concentration of drugs inside the bacteria and extruding the substances outside. Various extraneous substances, including antimicrobials, toxic heavy metals, dyes, and detergents, have been removed by this protective barrier composed of diverse transporter proteins found in between the cell membrane and the periplasm within the bacterial cell. In this review, multiple efflux pump families have been analytically and widely outlined, and their potential applications have been discussed in detail. Additionally, this review also discusses a variety of biological functions of efflux pumps, including their role in the formation of biofilms, quorum sensing, their survivability, and the virulence in bacteria, and the genes/proteins associated with efflux pumps have also been explored for their potential relevance to antimicrobial resistance and antibiotic residue detection. A final discussion centers around efflux pump inhibitors, particularly those derived from plants.
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18
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Kotecka K, Kawalek A, Modrzejewska-Balcerek M, Gawor J, Zuchniewicz K, Gromadka R, Bartosik AA. Functional Characterization of TetR-like Transcriptional Regulator PA3973 from Pseudomonas aeruginosa. Int J Mol Sci 2022; 23:ijms232314584. [PMID: 36498910 PMCID: PMC9736018 DOI: 10.3390/ijms232314584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/17/2022] [Accepted: 11/19/2022] [Indexed: 11/24/2022] Open
Abstract
Pseudomonas aeruginosa, a human opportunistic pathogen, is a common cause of nosocomial infections. Its ability to survive under different conditions relies on a complex regulatory network engaging transcriptional regulators controlling metabolic pathways and capabilities to efficiently use the available resources. P. aeruginosa PA3973 encodes an uncharacterized TetR family transcriptional regulator. In this study, we applied a transcriptome profiling (RNA-seq), genome-wide identification of binding sites using ChIP-seq, as well as the phenotype analyses to unravel the biological role of PA3973. Transcriptional profiling of P. aeruginosa PAO1161 overexpressing PA3973 showed changes in the mRNA level of 648 genes. Concomitantly, ChIP-seq analysis identified more than 300 PA3973 binding sites in the P. aeruginosa genome. A 13 bp sequence motif was indicated as the binding site of PA3973. The PA3973 regulon encompasses the PA3972-PA3971 genes encoding a probable acyl-CoA dehydrogenase and a thioesterase. In vitro analysis showed PA3973 binding to PA3973p. Accordingly, the lack of PA3973 triggered increased expression of PA3972 and PA3971. The ∆PA3972-71 PAO1161 strain demonstrated impaired growth in the presence of stress-inducing agents hydroxylamine or hydroxyurea, thus suggesting the role of PA3972-71 in pathogen survival upon stress. Overall our results showed that TetR-type transcriptional regulator PA3973 has multiple binding sites in the P. aeruginosa genome and influences the expression of diverse genes, including PA3972-PA3971, encoding proteins with a proposed role in stress response.
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19
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Meyer C, Lucaβen K, Gerson S, Xanthopoulou K, Wille T, Seifert H, Higgins PG. Contribution of RND-Type Efflux Pumps in Reduced Susceptibility to Biocides in Acinetobacter baumannii. Antibiotics (Basel) 2022; 11:1635. [PMID: 36421279 PMCID: PMC9686468 DOI: 10.3390/antibiotics11111635] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/11/2022] [Accepted: 11/15/2022] [Indexed: 07/30/2023] Open
Abstract
Bacterial efflux pumps are among the key mechanisms of resistance against antibiotics and biocides. We investigated whether differential expression levels of the RND-type efflux pumps AdeABC and AdeIJK impacted the susceptibility to commonly used biocides in multidrug-resistant Acinetobacter baumannii. Susceptibility testing and time-kill assays of defined laboratory and clinical A. baumannii strains with different levels of efflux pump expression were performed after exposure to the biocides benzalkonium chloride, chlorhexidine digluconate, ethanol, glucoprotamin, octenidine dihydrochloride, and triclosan. While the impact of efflux pump expression on susceptibility to the biocides was limited, noticeable differences were found in kill curves, where AdeABC expression correlated with greater survival after exposure to benzalkonium chloride, chlorhexidine digluconate, glucoprotamin, and octenidine dihydrochloride. AdeABC expression levels did not impact kill kinetics with ethanol nor triclosan. In conclusion, these data indicate that the overexpression of the RND-type efflux pumps AdeABC and AdeIJK contributes to the survival of A. baumannii when exposed to residual concentrations of biocides.
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Affiliation(s)
- Christina Meyer
- Institute for Medical Microbiology, Immunology and Hygiene, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50935 Cologne, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, 50935 Cologne, Germany
| | - Kai Lucaβen
- Institute for Medical Microbiology, Immunology and Hygiene, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50935 Cologne, Germany
| | - Stefanie Gerson
- Institute for Medical Microbiology, Immunology and Hygiene, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50935 Cologne, Germany
| | - Kyriaki Xanthopoulou
- Institute for Medical Microbiology, Immunology and Hygiene, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50935 Cologne, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, 50935 Cologne, Germany
| | - Thorsten Wille
- Institute for Medical Microbiology, Immunology and Hygiene, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50935 Cologne, Germany
| | - Harald Seifert
- Institute for Medical Microbiology, Immunology and Hygiene, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50935 Cologne, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, 50935 Cologne, Germany
| | - Paul G. Higgins
- Institute for Medical Microbiology, Immunology and Hygiene, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50935 Cologne, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, 50935 Cologne, Germany
- Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50935 Cologne, Germany
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Barnabas V, Kashyap A, Raja R, Newar K, Rai D, Dixit NM, Mehra S. The Extent of Antimicrobial Resistance Due to Efflux Pump Regulation. ACS Infect Dis 2022; 8:2374-2388. [PMID: 36264222 DOI: 10.1021/acsinfecdis.2c00460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A key mechanism driving antimicrobial resistance (AMR) stems from the ability of bacteria to up-regulate efflux pumps upon exposure to drugs. The resistance gained by this up-regulation is pliable because of the tight regulation of efflux pump levels. This leads to temporary enhancement in survivability of bacteria due to higher efflux pump levels in the presence of antibiotics, which can be reversed when the cells are no longer exposed to the drug. Knowledge of the extent of resistance thus gained would inform intervention strategies aimed at mitigating AMR. Here, we combine mathematical modeling and experiments to quantify the maximum extent of resistance that efflux pump up-regulation can confer via phenotypic induction in the presence of drugs and genotypic abrogation of regulation. Our model describes the dynamics of drug transport in and out of cells coupled with the associated regulation of efflux pump levels and predicts the increase in the minimum inhibitory concentration (MIC) of drugs due to such regulation. To test the model, we measured the uptake and efflux as well as the MIC of the compound ethidium bromide (EtBr), a substrate of the efflux pump LfrA, in wild-type Mycobacterium smegmatis mc2155, as well as in two laboratory-generated strains. Our model captured the observed EtBr levels and MIC fold-changes quantitatively. Further, the model identified key parameters associated with the resulting resistance, variations in which could underlie the extent to which such resistance arises across different drug-bacteria combinations, potentially offering tunable handles to optimize interventions aimed at minimizing AMR.
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Affiliation(s)
- Vinay Barnabas
- Department of Chemical Engineering, Indian Institute of Technology, Mumbai400076, India
| | - Akanksha Kashyap
- Department of Chemical Engineering, Indian Institute of Technology, Mumbai400076, India
| | - Rubesh Raja
- Department of Chemical Engineering, Indian Institute of Science, Bangalore560012, India
| | - Kapil Newar
- Department of Chemical Engineering, Indian Institute of Science, Bangalore560012, India
| | - Deepika Rai
- Department of Chemical Engineering, Indian Institute of Technology, Mumbai400076, India
| | - Narendra M Dixit
- Department of Chemical Engineering, Indian Institute of Science, Bangalore560012, India.,Centre for Biosystems Science and Engineering, Indian Institute of Science, Bangalore560012, India
| | - Sarika Mehra
- Department of Chemical Engineering, Indian Institute of Technology, Mumbai400076, India
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Su T, Che C, Han J, Zhao Y, Zhang Z, An G, Si M, Chen C. The TetR-type regulator AtsR is involved in multidrug response in Corynebacterium glutamicum. Microb Cell Fact 2022; 21:123. [PMID: 35729563 PMCID: PMC9210681 DOI: 10.1186/s12934-022-01850-0] [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: 03/22/2022] [Accepted: 06/05/2022] [Indexed: 11/10/2022] Open
Abstract
Background The TetR (tetracycline repressor) family is one of the major transcription factor families that regulate expression of genes involved in bacterial antimicrobial resistance systems. NCgl0886 protein, designated as AtsR, is a member of the TetR family identified in Corynebacterium glutamicum, which is conserved in several species of the genera Corynebacterium, also including the well-known pathogen C. diphtheriae. AtsR is located at no far upstream of the identically oriented ncgl0884 gene, encoding a putative multidrug efflux pump protein, and in the same operon with ncgl0887, encoding a resistance, nodulation and cell division (RND) superfamily drug exporter. However, the role of AtsR is not clearly understood. Results Here we showed that dimeric AtsR directly repressed the expression of the ncgl0887-atsR operon, as well as indirectly controlled the ncgl0884 transcription. Antibiotics and toxic compounds induced the expression of ncgl0887-atsR operon. A perfect palindromic motif (5΄-TGCAA-N2-TTGCA-3΄; 12 bp) was identified in the upstream region of ncgl0887-atsR operon. Electrophoretic mobility shift assays (EMSAs) demonstrated specific binding of AtsR to this motif, and hydrogen peroxide (H2O2) blocked binding. H2O2 oxidized cysteine residues to form Cys123-Cys187 intermolecular disulfide bonds between two subunits in AtsR dimer, which altered its DNA-binding characteristics and caused its dissociation, thereby leading to derepression of the drug efflux protein. Deletion of ncgl0884 and ncgl0887 increased the susceptibilities of C. glutamicum for several toxic compounds, but overexpression of atsR decreased the drug tolerance of C. glutamicum. Conclusions Our study revealed that AtsR was a redox regulator that sensed oxidative stress via thiol modification. The results obtained here will contribute to our understanding of the drug response mechanism not only in C. glutamicum but also in the related bacteria C. diphtheriae. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-022-01850-0.
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Affiliation(s)
- Tao Su
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, 273165, China.
| | - Chengchuan Che
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, 273165, China
| | - Jiyu Han
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, 273165, China
| | - Yuying Zhao
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, 273165, China
| | - Zihan Zhang
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, 273165, China
| | - Guangdi An
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, 273165, China
| | - Meiru Si
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, 273165, China
| | - Can Chen
- Key Laboratory of Plant Genetics and Molecular Breeding, College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou, Henan, 466001, China.
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Xu S, Wang X, Zhang F, Jiang Y, Zhang Y, Cheng M, Yan X, Hong Q, He J, Qiu J. PicR as a MarR Family Transcriptional Repressor Multiply Controls the Transcription of Picolinic Acid Degradation Gene Cluster pic in Alcaligenes faecalis JQ135. Appl Environ Microbiol 2022; 88:e0017222. [PMID: 35604228 PMCID: PMC9195942 DOI: 10.1128/aem.00172-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 04/29/2022] [Indexed: 11/20/2022] Open
Abstract
Picolinic acid (PA) is a natural toxic pyridine derivative as well as an important intermediate used in the chemical industry. In a previous study, we identified a gene cluster, pic, that responsible for the catabolism of PA in Alcaligenes faecalis JQ135. However, the transcriptional regulation of the pic cluster remains known. This study showed that the entire pic cluster was composed of 17 genes and transcribed as four operons: picR, picCDEF, picB4B3B2B1, and picT1A1A2A3T2T3MN. Deletion of picR, encoding a putative MarR-type regulator, greatly shortened the lag phase of PA degradation. An electrophoretic mobility shift assay and DNase I footprinting showed that PicR has one binding site in the picR-picC intergenic region and two binding sites in the picB-picT1 intergenic region. The DNA sequences of the three binding sites have the palindromic characteristics of TCAG-N4-CTNN: the space consists of four nonspecific bases, and the four palindromic bases on the left and the first two palindromic bases on the right are strictly conserved, while the last two bases on the right vary among the three binding sites. An in vivo β-galactosidase activity reporter assay indicated that 6-hydroxypicolinic acid but not PA acted as a ligand of PicR, preventing PicR from binding to promoter regions and thus derepressing the transcription of the pic cluster. This study revealed the negative transcriptional regulation mechanism of PA degradation by PicR in A. faecalis JQ135 and provides new insights into the structure and function of the MarR-type regulator. IMPORTANCE The pic gene cluster was found to be responsible for PA degradation and widely distributed in Alpha-, Beta-, and Gammaproteobacteria. Thus, it is very necessary to understand the regulation mechanism of the pic cluster in these strains. This study revealed that PicR binds to three sites of the promoter regions of the pic cluster to multiply regulate the transcription of the pic cluster, which enables A. faecalis JQ135 to efficiently utilize PA. Furthermore, the study also found a unique palindrome sequence for binding of the MarR-type regulator. This study enhanced our understanding of microbial catabolism of environmental toxic pyridine derivatives.
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Affiliation(s)
- Siqiong Xu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Xiao Wang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Fuyin Zhang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Yinhu Jiang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Yanting Zhang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Minggen Cheng
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Xin Yan
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Qing Hong
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Jian He
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Jiguo Qiu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
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Dashtbani-Roozbehani A, Brown MH. Efflux Pump Mediated Antimicrobial Resistance by Staphylococci in Health-Related Environments: Challenges and the Quest for Inhibition. Antibiotics (Basel) 2021; 10:antibiotics10121502. [PMID: 34943714 PMCID: PMC8698293 DOI: 10.3390/antibiotics10121502] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 11/30/2021] [Accepted: 11/30/2021] [Indexed: 01/04/2023] Open
Abstract
The increasing emergence of antimicrobial resistance in staphylococcal bacteria is a major health threat worldwide due to significant morbidity and mortality resulting from their associated hospital- or community-acquired infections. Dramatic decrease in the discovery of new antibiotics from the pharmaceutical industry coupled with increased use of sanitisers and disinfectants due to the ongoing COVID-19 pandemic can further aggravate the problem of antimicrobial resistance. Staphylococci utilise multiple mechanisms to circumvent the effects of antimicrobials. One of these resistance mechanisms is the export of antimicrobial agents through the activity of membrane-embedded multidrug efflux pump proteins. The use of efflux pump inhibitors in combination with currently approved antimicrobials is a promising strategy to potentiate their clinical efficacy against resistant strains of staphylococci, and simultaneously reduce the selection of resistant mutants. This review presents an overview of the current knowledge of staphylococcal efflux pumps, discusses their clinical impact, and summarises compounds found in the last decade from plant and synthetic origin that have the potential to be used as adjuvants to antibiotic therapy against multidrug resistant staphylococci. Critically, future high-resolution structures of staphylococcal efflux pumps could aid in design and development of safer, more target-specific and highly potent efflux pump inhibitors to progress into clinical use.
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Pswarayi F, Qiao N, Gaur G, Gänzle M. Antimicrobial plant secondary metabolites, MDR transporters and antimicrobial resistance in cereal-associated lactobacilli: is there a connection? Food Microbiol 2021; 102:103917. [PMID: 34809942 DOI: 10.1016/j.fm.2021.103917] [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: 07/09/2021] [Revised: 09/19/2021] [Accepted: 09/24/2021] [Indexed: 11/27/2022]
Abstract
Cereal-associated lactobacilli resist antimicrobial plant secondary metabolites. This study aimed to identify multi-drug-resistance (MDR) transporters in isolates from mahewu, a Zimbabwean fermented cereal beverage, and to determine whether these MDR-transporters relate to resistance against phenolic compounds and antibiotics. Comparative genomic analyses indicated that all seven mahewu isolates harbored multiple MATE and MFS MDR proteins. Strains of Lactiplantibacillus plantarum and Limosilactobacillus fermentum encoded for the same gene, termed mahewu phenolics resistance gene mprA, with more than 99% nucleotide identity, suggesting horizontal gene transfer. Strains of Lp. plantarum were more resistant than strains of Lm. fermentum to phenolic acids, other antimicrobials and antibiotics but the origins of strains were not related to resistance. The resistance of several strains exceeded EFSA thresholds for several antibiotics. Analysis of gene expression in one strain each of Lp. plantarum and Lm. fermentum revealed that at least one MDR gene in each strain was over-expressed during growth in wheat, sorghum and millet relative to growth in MRS5 broth. In addition, both strains over-expressed a phenolic acid reductase. The results suggest that diverse lactobacilli in mahewu share MDR transporters acquired by lateral gene transfer, and that these transporters mediate resistance to secondary plant metabolites and antibiotics.
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Affiliation(s)
- Felicitas Pswarayi
- University of Alberta, Department of Agricultural, Food and Nutritional Science, Edmonton, Canada
| | - Nanzhen Qiao
- University of Alberta, Department of Agricultural, Food and Nutritional Science, Edmonton, Canada
| | - Gautam Gaur
- University of Alberta, Department of Agricultural, Food and Nutritional Science, Edmonton, Canada
| | - Michael Gänzle
- University of Alberta, Department of Agricultural, Food and Nutritional Science, Edmonton, Canada.
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Rusu A, Lungu IA, Moldovan OL, Tanase C, Hancu G. Structural Characterization of the Millennial Antibacterial (Fluoro)Quinolones-Shaping the Fifth Generation. Pharmaceutics 2021; 13:pharmaceutics13081289. [PMID: 34452252 PMCID: PMC8399897 DOI: 10.3390/pharmaceutics13081289] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 08/12/2021] [Accepted: 08/14/2021] [Indexed: 12/12/2022] Open
Abstract
The evolution of the class of antibacterial quinolones includes the introduction in therapy of highly successful compounds. Although many representatives were withdrawn due to severe adverse reactions, a few representatives have proven their therapeutical value over time. The classification of antibacterial quinolones into generations is a valuable tool for physicians, pharmacists, and researchers. In addition, the transition from one generation to another has brought new representatives with improved properties. In the last two decades, several representatives of antibacterial quinolones received approval for therapy. This review sets out to chronologically outline the group of approved antibacterial quinolones since 2000. Special attention is given to eight representatives: besifloxacin, delafoxacin, finafloxacin, lascufloxacin, nadifloxacin and levonadifloxacin, nemonoxacin, and zabofloxacin. These compounds have been characterized regarding physicochemical properties, formulations, antibacterial activity spectrum and advantageous structural characteristics related to antibacterial efficiency. At present these new compounds (with the exception of nadifloxacin) are reported differently, most often in the fourth generation and less frequently in a new generation (the fifth). Although these new compounds' mechanism does not contain essential new elements, the question of shaping a new generation (the fifth) arises, based on higher potency and broad spectrum of activity, including resistant bacterial strains. The functional groups that ensured the biological activity, good pharmacokinetic properties and a safety profile were highlighted. In addition, these new representatives have a low risk of determining bacterial resistance. Several positive aspects are added to the fourth fluoroquinolones generation, characteristics that can be the basis of the fifth generation. Antibacterial quinolones class continues to acquire new compounds with antibacterial potential, among other effects. Numerous derivatives, hybrids or conjugates are currently in various stages of research.
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Affiliation(s)
- Aura Rusu
- Pharmaceutical and Therapeutical Chemistry Department, Faculty of Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540142 Targu Mures, Romania; (A.R.); (G.H.)
| | - Ioana-Andreea Lungu
- The Doctoral School of Medicine and Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540142 Targu Mures, Romania; (I.-A.L.); (O.-L.M.)
| | - Octavia-Laura Moldovan
- The Doctoral School of Medicine and Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540142 Targu Mures, Romania; (I.-A.L.); (O.-L.M.)
| | - Corneliu Tanase
- Pharmaceutical Botany Department, Faculty of Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540142 Targu Mures, Romania
- Correspondence: ; Tel.: +40-744-215-543
| | - Gabriel Hancu
- Pharmaceutical and Therapeutical Chemistry Department, Faculty of Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540142 Targu Mures, Romania; (A.R.); (G.H.)
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Pasqua M, Bonaccorsi di Patti MC, Fanelli G, Utsumi R, Eguchi Y, Trirocco R, Prosseda G, Grossi M, Colonna B. Host - Bacterial Pathogen Communication: The Wily Role of the Multidrug Efflux Pumps of the MFS Family. Front Mol Biosci 2021; 8:723274. [PMID: 34381818 PMCID: PMC8350985 DOI: 10.3389/fmolb.2021.723274] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 07/13/2021] [Indexed: 12/23/2022] Open
Abstract
Bacterial pathogens are able to survive within diverse habitats. The dynamic adaptation to the surroundings depends on their ability to sense environmental variations and to respond in an appropriate manner. This involves, among others, the activation of various cell-to-cell communication strategies. The capability of the bacterial cells to rapidly and co-ordinately set up an interplay with the host cells and/or with other bacteria facilitates their survival in the new niche. Efflux pumps are ubiquitous transmembrane transporters, able to extrude a large set of different molecules. They are strongly implicated in antibiotic resistance since they are able to efficiently expel most of the clinically relevant antibiotics from the bacterial cytoplasm. Besides antibiotic resistance, multidrug efflux pumps take part in several important processes of bacterial cell physiology, including cell to cell communication, and contribute to increase the virulence potential of several bacterial pathogens. Here, we focus on the structural and functional role of multidrug efflux pumps belonging to the Major Facilitator Superfamily (MFS), the largest family of transporters, highlighting their involvement in the colonization of host cells, in virulence and in biofilm formation. We will offer an overview on how MFS multidrug transporters contribute to bacterial survival, adaptation and pathogenicity through the export of diverse molecules. This will be done by presenting the functions of several relevant MFS multidrug efflux pumps in human life-threatening bacterial pathogens as Staphylococcus aureus, Listeria monocytogenes, Klebsiella pneumoniae, Shigella/E. coli, Acinetobacter baumannii.
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Affiliation(s)
- Martina Pasqua
- Department of Biology and Biotechnology "C. Darwin", Istituto Pasteur Italia, Sapienza Università di Roma, Rome, Italy
| | | | - Giulia Fanelli
- Department of Biology and Biotechnology "C. Darwin", Istituto Pasteur Italia, Sapienza Università di Roma, Rome, Italy
| | - Ryutaro Utsumi
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Osaka, Japan
| | - Yoko Eguchi
- Department of Science and Technology on Food Safety, Kindai University, Kinokawa, Japan
| | - Rita Trirocco
- Department of Biology and Biotechnology "C. Darwin", Istituto Pasteur Italia, Sapienza Università di Roma, Rome, Italy
| | - Gianni Prosseda
- Department of Biology and Biotechnology "C. Darwin", Istituto Pasteur Italia, Sapienza Università di Roma, Rome, Italy
| | - Milena Grossi
- Department of Biology and Biotechnology "C. Darwin", Istituto Pasteur Italia, Sapienza Università di Roma, Rome, Italy
| | - Bianca Colonna
- Department of Biology and Biotechnology "C. Darwin", Istituto Pasteur Italia, Sapienza Università di Roma, Rome, Italy
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Praski Alzrigat L, Huseby DL, Brandis G, Hughes D. Resistance/fitness trade-off is a barrier to the evolution of MarR inactivation mutants in Escherichia coli. J Antimicrob Chemother 2021; 76:77-83. [PMID: 33089314 PMCID: PMC7729382 DOI: 10.1093/jac/dkaa417] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 09/09/2020] [Indexed: 12/23/2022] Open
Abstract
Background Mutations that inactivate MarR reduce susceptibility to ciprofloxacin and competitive growth fitness in Escherichia coli. Both phenotypes are caused by overexpression of the MarA regulon, which includes the AcrAB-TolC drug efflux pump. Objectives We asked whether compensatory evolution could reduce the fitness cost of MarR-inactivating mutations without affecting resistance to ciprofloxacin. Methods The cost of overexpressing the AcrAB-TolC efflux pump was measured independently of MarA overexpression. Experimental evolution of MarR-inactive strains was used to select mutants with increased fitness. The acquired mutations were identified and their effects on drug susceptibility were measured. Results Overexpression of the AcrAB-TolC efflux pump was found not to contribute to the fitness cost of MarA regulon overexpression. Fitness-compensatory mutations were selected in marA and lon. The mutations reduced the level of MarA protein thus reducing expression of the MarA regulon. They restored growth fitness but also reduced resistance to ciprofloxacin. Conclusions The fitness cost caused by overexpression of the MarA regulon has multiple contributing factors. Experimental evolution did not identify any single pump-independent cost factor. Instead, efficient fitness compensation occurred only by mechanisms that reduce MarA concentration, which simultaneously reduce the drug resistance phenotype. This resistance/fitness trade-off is a barrier to the successful spread of MarR inactivation mutations in clinical isolates where growth fitness is essential.
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Affiliation(s)
- Lisa Praski Alzrigat
- Department of Medical Biochemistry and Microbiology, Box 582 Biomedical Center, Uppsala University, Sweden
| | - Douglas L Huseby
- Department of Medical Biochemistry and Microbiology, Box 582 Biomedical Center, Uppsala University, Sweden
| | - Gerrit Brandis
- Department of Medical Biochemistry and Microbiology, Box 582 Biomedical Center, Uppsala University, Sweden
| | - Diarmaid Hughes
- Department of Medical Biochemistry and Microbiology, Box 582 Biomedical Center, Uppsala University, Sweden
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Liu Y, Yang W, Su T, Che C, Li G, Chen C, Si M. The cssR gene of Corynebacterium glutamicum plays a negative regulatory role in stress responses. Microb Cell Fact 2021; 20:110. [PMID: 34082775 PMCID: PMC8176726 DOI: 10.1186/s12934-021-01600-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 05/25/2021] [Indexed: 12/19/2022] Open
Abstract
Background CssR, the product of the Corynebacterium glutamicum ncgl1578 gene cotranscribed with ncgl1579, is a TetR (tetracycline regulator) family repressor. Although many TetR-type regulators in C. glutamicum have been extensively described, members of the TetR family involved in the stress response remain unidentified. Results In this study, we found that CssR regulated the transcription of its own gene and the ncgl1576-ncgl1577 operon. The ncgl1576-ncgl1577 operon, which is located upstream of cssR in the orientation opposite that of the cssR operon, encodes an ATP-binding cassette (ABC), some of which are involved in the export of a wide range of antimicrobial compounds. The cssR-deletion (ΔcssR) mutant displayed increased resistance to various stresses. An imperfect palindromic motif (5′-TAA(G)TGN13CA(G)TTA-3′; 25 bp) located at the intergenic region between cssR and ncgl1577 was identified as the sole binding site for CssR. Expression of cssR and ncgl1577 was induced by antibiotics and heavy metals but not H2O2 or diamide, and the DNA-binding activity of CssR was impaired by antibiotics and heavy metals but not H2O2. Antibiotics and heavy metals caused CssR dissociation from target gene promoters, thus derepressing their transcription. Oxidant treatment neither altered the conformation of CssR nor modified its cysteine residues, indicating that the cysteine residues in CssR have no redox activity. In the ΔcssR mutant strain, genes involved in redox homeostasis also showed increased transcription levels, and the NADPH/NADP+ ratio was higher than that of the parental strain. Conclusion The stress response mechanism of CssR in C. glutamicum is realized via ligand-induced conformational changes of the protein, not via cysteine oxidation-based thiol modification. Moreover, the crucial role of CssR in the stress response was demonstrated by negatively controlling the expression of the ncgl1576-ncgl1577 operon, its structural gene, and/or redox homeostasis-related genes. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-021-01600-8.
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Affiliation(s)
- Yang Liu
- College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China
| | - Wenzhi Yang
- School of Food Science and Nutrition, University of Leeds, Leeds, LS2 9JT, UK
| | - Tao Su
- College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China
| | - Chengchuan Che
- College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China
| | - Guizhi Li
- College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China
| | - Can Chen
- Key Laboratory of Plant Genetics and Molecular Breeding, Henan Key Laboratory of Crop Molecular Breeding & Bioreactor, College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou, 466001, Henan, China.
| | - Meiru Si
- College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China.
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The thiol oxidation-based sensing and regulation mechanism for the OasR-mediated organic peroxide and antibiotic resistance in C. glutamicum. Biochem J 2021; 477:3709-3727. [PMID: 32926092 DOI: 10.1042/bcj20200533] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/07/2020] [Accepted: 09/14/2020] [Indexed: 12/19/2022]
Abstract
Corynebacterium glutamicum, an important industrial and model microorganism, inevitably encountered stress environment during fermentative process. Therefore, the ability of C. glutamicum to withstand stress and maintain the cellular redox balance was vital for cell survival and enhancing fermentation efficiency. To robustly survive, C. glutamicum has been equipped with many types of redox sensors. Although cysteine oxidation-based peroxide-sensing regulators have been well described in C. glutamicum, redox sensors involving in multiple environmental stress response remained elusive. Here, we reported an organic peroxide- and antibiotic-sensing MarR (multiple antibiotics resistance regulators)-type regulator, called OasR (organic peroxide- and antibiotic-sensing regulator). The OasR regulator used Cys95 oxidation to sense oxidative stress to form S-mycothiolated monomer or inter-molecular disulfide-containing dimer, resulting in its dissociation from the target DNA promoter. Transcriptomics uncovered the strong up-regulation of many multidrug efflux pump genes and organic peroxide stress-involving genes in oasR mutant, consistent with the phenomenon that oasR mutant showed a reduction in sensitivity to antibiotic and organic peroxide. Importantly, the addition of stress-associated ligands such as cumene hydroperoxide and streptomycin induced oasR and multidrug efflux pump protein NCgl1020 expression in vivo. We speculated that cell resistance to antibiotics and organic peroxide correlated with stress response-induced up-regulation of genes expression. Together, the results revealed that OasR was a key MarR-type redox stress-responsive transcriptional repressor, and sensed oxidative stress generated through hydroxyl radical formation to mediate antibiotic resistance in C. glutamicum.
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Pan X, Cen Y, Kuang M, Li B, Qin R, Zhou H. Artesunate interrupts the self-transcriptional activation of MarA to inhibit RND family pumps of Escherichia coli. Int J Med Microbiol 2020; 310:151465. [PMID: 33238228 DOI: 10.1016/j.ijmm.2020.151465] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 10/14/2020] [Accepted: 11/05/2020] [Indexed: 11/25/2022] Open
Abstract
Resistance-Nodulation-Division (RND) family pumps are responsible for producing multidrug resistance in Escherichia coli; however, there has been little study of targeted inhibitors of RNDs. In the present study, we investigated the inhibition of RND pumps by artesunate (AS) in E. coli, and further investigated the mechanism with respect to MarA, a regulator of RNDs. Although AS had no direct antibacterial effect, it showed a synergistic effect in combination with β-lactams against E. coli ATCC35218 in vitro and in vivo, suggesting it possesses antibacterial enhancement activity. Notably, AS, alone or in combination with β-lactams, downregulated the mRNA expression levels of marA, soxS, and rob, known as the marA-soxS-rob regulon, which then decreased the expression levels of RNDs, thereby increased ampicillin accumulation within ATCC35218. Using gene-deletion strains, we found that the antibacterial sensitization effect of AS persisted in wildtype bacteria, but was completely lost in the strain lacking marA, and decreased in the strain lacking soxS or rob, suggesting marA plays a crucial role in the sensitization of AS. Critically, we showed that AS inhibited the binding of MarA to the promoter of marA itself, not acrB, resulting in decreased mRNA expression of both acrB and marA. Mechanistically, we found AS directly bound to the central cavity of MarA through the R59 and K62 residues, and thus altered the charge distribution of MarA to interrupt the recognition between MarA and its promoter. We concluded that AS interrupts the self-transcriptional activation of MarA, thereby inhibits MarA-dependent mRNA expression of marA, acrAB, and tolC, and also certain other RNDs and regulatory genes related to MarA. Therefore, AS is a novel inhibitor of RND pumps that acts on the regulator MarA.
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Affiliation(s)
- Xichun Pan
- Department of Pharmacology, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing 400038, PR China
| | - Yanyan Cen
- Department of Pharmacology, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing 400038, PR China
| | - Mei Kuang
- Department of Pharmacology, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing 400038, PR China
| | - Bin Li
- Department of Pharmacology, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing 400038, PR China
| | - Rongxin Qin
- Department of Pharmacology, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing 400038, PR China
| | - Hong Zhou
- Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, 563003, PR China.
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Flores-Bautista E, Hernandez-Guerrero R, Huerta-Saquero A, Tenorio-Salgado S, Rivera-Gomez N, Romero A, Ibarra JA, Perez-Rueda E. Deciphering the functional diversity of DNA-binding transcription factors in Bacteria and Archaea organisms. PLoS One 2020; 15:e0237135. [PMID: 32822422 PMCID: PMC7446807 DOI: 10.1371/journal.pone.0237135] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 07/20/2020] [Indexed: 11/18/2022] Open
Abstract
DNA-binding Transcription Factors (TFs) play a central role in regulation of gene expression in prokaryotic organisms, and similarities at the sequence level have been reported. These proteins are predicted with different abundances as a consequence of genome size, where small organisms contain a low proportion of TFs and large genomes contain a high proportion of TFs. In this work, we analyzed a collection of 668 experimentally validated TFs across 30 different species from diverse taxonomical classes, including Escherichia coli K-12, Bacillus subtilis 168, Corynebacterium glutamicum, and Streptomyces coelicolor, among others. This collection of TFs, together with 111 hidden Markov model profiles associated with DNA-binding TFs collected from diverse databases such as PFAM and DBD, was used to identify the repertoire of proteins putatively devoted to gene regulation in 1321 representative genomes of Archaea and Bacteria. The predicted regulatory proteins were posteriorly analyzed in terms of their genomic context, allowing the prediction of functions for TFs and their neighbor genes, such as genes involved in virulence, enzymatic functions, phosphorylation mechanisms, and antibiotic resistance. The functional analysis associated with PFAM groups showed diverse functional categories were significantly enriched in the collection of TFs and the proteins encoded by the neighbor genes, in particular, small-molecule binding and amino acid transmembrane transporter activities associated with the LysR family and proteins devoted to cellular aromatic compound metabolic processes or responses to drugs, stress, or abiotic stimuli in the MarR family. We consider that with the increasing data derived from new technologies, novel TFs can be identified and help improve the predictions for this class of proteins in complete genomes. The complete collection of experimentally characterized and predicted TFs is available at http://web.pcyt.unam.mx/EntrafDB/.
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Affiliation(s)
- Emanuel Flores-Bautista
- Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas, Universidad Nacional Autónoma de México, Unidad Académica Yucatán, Mérida, Yucatán, México
| | - Rafael Hernandez-Guerrero
- Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas, Universidad Nacional Autónoma de México, Unidad Académica Yucatán, Mérida, Yucatán, México
| | - Alejandro Huerta-Saquero
- Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Ensenada, Baja California, México
| | - Silvia Tenorio-Salgado
- Tecnológico Nacional de México, Instituto Tecnológico de Mérida, Mérida, Yucatán, México
| | | | - Alba Romero
- Microbiota Host Interactions and Clostridia Research Group, Universidad Nacional Andrés Bello, Santiago de Chile, Chile
| | - Jose Antonio Ibarra
- Laboratorio de Genética Microbiana, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, México
| | - Ernesto Perez-Rueda
- Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas, Universidad Nacional Autónoma de México, Unidad Académica Yucatán, Mérida, Yucatán, México
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
- * E-mail:
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Ferrand A, Vergalli J, Pagès JM, Davin-Regli A. An Intertwined Network of Regulation Controls Membrane Permeability Including Drug Influx and Efflux in Enterobacteriaceae. Microorganisms 2020; 8:E833. [PMID: 32492979 PMCID: PMC7355843 DOI: 10.3390/microorganisms8060833] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 05/29/2020] [Accepted: 05/31/2020] [Indexed: 12/19/2022] Open
Abstract
The transport of small molecules across membranes is a pivotal step for controlling the drug concentration into the bacterial cell and it efficiently contributes to the antibiotic susceptibility in Enterobacteriaceae. Two types of membrane transports, passive and active, usually represented by porins and efflux pumps, are involved in this process. Importantly, the expression of these transporters and channels are modulated by an armamentarium of tangled regulatory systems. Among them, Helix-turn-Helix (HTH) family regulators (including the AraC/XylS family) and the two-component systems (TCS) play a key role in bacterial adaptation to environmental stresses and can manage a decrease of porin expression associated with an increase of efflux transporters expression. In the present review, we highlight some recent genetic and functional studies that have substantially contributed to our better understanding of the sophisticated mechanisms controlling the transport of small solutes (antibiotics) across the membrane of Enterobacteriaceae. This information is discussed, taking into account the worrying context of clinical antibiotic resistance and fitness of bacterial pathogens. The localization and relevance of mutations identified in the respective regulation cascades in clinical resistant strains are discussed. The possible way to bypass the membrane/transport barriers is described in the perspective of developing new therapeutic targets to combat bacterial resistance.
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Affiliation(s)
| | | | | | - Anne Davin-Regli
- UMR_MD1, U-1261, Aix-Marseille University, INSERM, SSA, IRBA, MCT, Faculté de Pharmacie, 27 Bd Jean Moulin, 13385 Marseille CEDEX 05, France; (A.F.); (J.V.); (J.-M.P.)
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Alkhalifa S, Jennings MC, Granata D, Klein M, Wuest WM, Minbiole KPC, Carnevale V. Analysis of the Destabilization of Bacterial Membranes by Quaternary Ammonium Compounds: A Combined Experimental and Computational Study. Chembiochem 2020; 21:1510-1516. [PMID: 31859426 PMCID: PMC7237276 DOI: 10.1002/cbic.201900698] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Indexed: 12/24/2022]
Abstract
The mechanism of action of quaternary ammonium compound (QAC) antiseptics has long been assumed to be straightforward membrane disruption, although the process of approaching and entering the membrane has little modeling precedent. Furthermore, questions have more recently arisen regarding bacterial resistance mechanisms, and why select classes of QACs (specifically, multicationic QACs) are less prone to resistance. In order to better understand such subtleties, a series of molecular dynamics simulations were utilized to help identify these molecular determinants, directly comparing mono-, bis-, and triscationic QACs in simulated membrane intercalation models. Three distinct membranes were simulated, mimicking the surfaces of Escherichia coli and Staphylococcus aureus, as well as a neutral phospholipid control. By analyzing the resulting trajectories in the form of a timeseries analysis, insight was gleaned regarding the significant steps and interactions involved in the destabilization of phospholipid bilayers within the bacterial membranes. Finally, to more specifically probe the effect of the hydrophobic section of the amphiphile that presumably penetrates the membrane, a series of alkyl- and ester-based biscationic quaternary ammonium compounds were prepared, tested for antimicrobial activity against both Gram-positive and Gram-negative bacteria, and modeled.
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Affiliation(s)
- Saleh Alkhalifa
- Department of Chemistry, Villanova University, 800 East Lancaster Avenue, Villanova, PA, 19085, USA
| | - Megan C Jennings
- Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, PA, 19122, USA
| | - Daniele Granata
- Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, PA, 19122, USA
| | - Michael Klein
- Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, PA, 19122, USA
| | - William M Wuest
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, GA, 30322, USA
- Emory Antibiotic Resistance Center, Emory University School of Medicine, 201 Dowman Drive, Atlanta, GA, 30322, USA
| | - Kevin P C Minbiole
- Department of Chemistry, Villanova University, 800 East Lancaster Avenue, Villanova, PA, 19085, USA
| | - Vincenzo Carnevale
- Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, PA, 19122, USA
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Ullrich T, Weirich S, Jeltsch A. Development of an epigenetic tetracycline sensor system based on DNA methylation. PLoS One 2020; 15:e0232701. [PMID: 32379807 PMCID: PMC7205209 DOI: 10.1371/journal.pone.0232701] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 04/19/2020] [Indexed: 12/17/2022] Open
Abstract
Bacterial live cell sensors are potentially powerful tools for the detection of environmental toxins. In this work, we have established and validated a flow cytometry readout for an existing bacterial arabinose sensor system with DNA methylation based memory function (Maier et al., 2017, Nat. Comm., 8:15336). Flow cytometry readout is convenient and enables a multiparameter analysis providing information about single-cell variability, which is beneficial for further development of sensor systems of this type in the future. We then designed a tetracycline sensor system, because of the importance of antibiotics pollution in the light of multi-resistant pathogens. To this end, a tetracycline trigger plasmid was constructed by replacing the araC repressor gene and the ara operator of the arabinose trigger plasmid with the tetR gene coding for the tetracycline repressor and the tet operon. After combination with the memory plasmid, the tetracycline sensor system was shown to be functional in E. coli allowing to detect and memorize the presence of tetracycline. Due to a positive feedback between the trigger and memory systems, the combined whole-cell biosensor showed a very high sensitivity for tetracycline with a detection threshold at 0.1 ng/ml tetracycline, which may be a general property of sensors of this type. Moreover, acute presence of tetracycline and past exposure can be detected by this sensor using the dual readout of two reporter fluorophores.
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Affiliation(s)
- Timo Ullrich
- Department of Biochemistry, Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, Stuttgart, Germany
| | - Sara Weirich
- Department of Biochemistry, Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, Stuttgart, Germany
| | - Albert Jeltsch
- Department of Biochemistry, Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, Stuttgart, Germany
- * E-mail:
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35
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Leveson-Gower RB, Mayer C, Roelfes G. The importance of catalytic promiscuity for enzyme design and evolution. Nat Rev Chem 2019. [DOI: 10.1038/s41570-019-0143-x] [Citation(s) in RCA: 121] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Veloo ACM, Chlebowicz M, Winter HLJ, Bathoorn D, Rossen JWA. Three metronidazole-resistant Prevotella bivia strains harbour a mobile element, encoding a novel nim gene, nimK, and an efflux small MDR transporter. J Antimicrob Chemother 2019; 73:2687-2690. [PMID: 29982676 PMCID: PMC6148209 DOI: 10.1093/jac/dky236] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 05/24/2018] [Indexed: 01/05/2023] Open
Abstract
Objectives In this study we assess the antibiotic resistance genes in three metronidazole-resistant Prevotella bivia clinical isolates. Methods Strains were whole-genome sequenced. De novo assembly was performed and genes were annotated in RAST. Manual adjustments were made, when required, to the annotation and length of the genes. Results In all three strains a novel nim gene, nimK, was encountered located on a mobile genetic element (MGE). The nimK gene was associated with an IS1380 family transposase. On the same MGE, genes encoding an efflux small MDR (SMR) transporter were present and were associated with a crp/fnr regulator. Conclusions This is the first description of the presence of a novel nim gene in metronidazole-resistant P. bivia clinical isolates. This gene is co-located with an efflux SMR transporter on an MGE, which has been named Tn6456 (MG827401). The identification of these resistance genes on an MGE is worrisome, since this indicates the horizontal gene transfer of antibiotic and/or biocide resistance from one strain to the other.
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Affiliation(s)
- A C M Veloo
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - M Chlebowicz
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - H L J Winter
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - D Bathoorn
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - J W A Rossen
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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Pasqua M, Grossi M, Zennaro A, Fanelli G, Micheli G, Barras F, Colonna B, Prosseda G. The Varied Role of Efflux Pumps of the MFS Family in the Interplay of Bacteria with Animal and Plant Cells. Microorganisms 2019; 7:microorganisms7090285. [PMID: 31443538 PMCID: PMC6780985 DOI: 10.3390/microorganisms7090285] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 08/19/2019] [Accepted: 08/21/2019] [Indexed: 12/20/2022] Open
Abstract
Efflux pumps represent an important and large group of transporter proteins found in all organisms. The importance of efflux pumps resides in their ability to extrude a wide range of antibiotics, resulting in the emergence of multidrug resistance in many bacteria. Besides antibiotics, multidrug efflux pumps can also extrude a large variety of compounds: Bacterial metabolites, plant-produced compounds, quorum-sensing molecules, and virulence factors. This versatility makes efflux pumps relevant players in interactions not only with other bacteria, but also with plant or animal cells. The multidrug efflux pumps belonging to the major facilitator superfamily (MFS) are widely distributed in microbial genomes and exhibit a large spectrum of substrate specificities. Multidrug MFS efflux pumps are present either as single-component transporters or as tripartite complexes. In this review, we will summarize how the multidrug MFS efflux pumps contribute to the interplay between bacteria and targeted host cells, with emphasis on their role in bacterial virulence, in the colonization of plant and animal host cells and in biofilm formation. We will also address the complexity of these interactions in the light of the underlying regulatory networks required for the effective activation of efflux pump genes.
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Affiliation(s)
- Martina Pasqua
- Istituto Pasteur Italia, Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Via dei Sardi 70, 00185 Rome, Italy
| | - Milena Grossi
- Istituto Pasteur Italia, Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Via dei Sardi 70, 00185 Rome, Italy
| | - Alessandro Zennaro
- Istituto Pasteur Italia, Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Via dei Sardi 70, 00185 Rome, Italy
| | - Giulia Fanelli
- Istituto Pasteur Italia, Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Via dei Sardi 70, 00185 Rome, Italy
| | - Gioacchino Micheli
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche (CNR), P.le A. Moro 5, 00185 Roma, Italy
| | - Frederic Barras
- Département de Microbiologie, Institut Pasteur, 75015 Paris, France
- Équipe de Recherche Labellisée (ERL) Microbiology, Centre National de la Recherche Scientifique (CNRS), 13009 Marseille, France
| | - Bianca Colonna
- Istituto Pasteur Italia, Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Via dei Sardi 70, 00185 Rome, Italy
| | - Gianni Prosseda
- Istituto Pasteur Italia, Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Via dei Sardi 70, 00185 Rome, Italy.
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McManus JB, Emanuel PA, Murray RM, Lux MW. A method for cost-effective and rapid characterization of engineered T7-based transcription factors by cell-free protein synthesis reveals insights into the regulation of T7 RNA polymerase-driven expression. Arch Biochem Biophys 2019; 674:108045. [PMID: 31326518 DOI: 10.1016/j.abb.2019.07.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 06/26/2019] [Accepted: 07/13/2019] [Indexed: 12/20/2022]
Abstract
The T7 bacteriophage RNA polymerase (T7 RNAP) serves as a model for understanding RNA synthesis, as a tool for protein expression, and as an actuator for synthetic gene circuit design in bacterial cells and cell-free extract. T7 RNAP is an attractive tool for orthogonal protein expression in bacteria owing to its compact single subunit structure and orthogonal promoter specificity. Understanding the mechanisms underlying T7 RNAP regulation is important to the design of engineered T7-based transcription factors, which can be used in gene circuit design. To explore regulatory mechanisms for T7 RNAP-driven expression, we developed a rapid and cost-effective method to characterize engineered T7-based transcription factors using cell-free protein synthesis and an acoustic liquid handler. Using this method, we investigated the effects of the tetracycline operator's proximity to the T7 promoter on the regulation of T7 RNAP-driven expression. Our results reveal a mechanism for regulation that functions by interfering with the transition of T7 RNAP from initiation to elongation and validates the use of the method described here to engineer future T7-based transcription factors.
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Affiliation(s)
- John B McManus
- Army Research Laboratory - West Campus, California Institute of Technology, 1200 East California Blvd, Pasadena, CA, 91125, USA
| | - Peter A Emanuel
- US Army Combat Capabilities Development Command Chemical Biological Center, 8198 Blackhawk Rd, APG, MD, 21010, USA
| | - Richard M Murray
- California Institute of Technology, Biology and Biological Engineering, 1200 East California Blvd, Pasadena, CA, 91125, USA
| | - Matthew W Lux
- US Army Combat Capabilities Development Command Chemical Biological Center, 8198 Blackhawk Rd, APG, MD, 21010, USA.
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Wang T, Kunze C, Dunlop MJ. Salicylate Increases Fitness Cost Associated with MarA-Mediated Antibiotic Resistance. Biophys J 2019; 117:563-571. [PMID: 31349991 DOI: 10.1016/j.bpj.2019.07.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 06/21/2019] [Accepted: 07/02/2019] [Indexed: 01/12/2023] Open
Abstract
Antibiotic resistance is generally associated with a fitness deficit resulting from the burden of producing and maintaining resistance machinery. This additional cost suggests that resistant bacteria will be outcompeted by susceptible bacteria in conditions without antibiotics. However, in practice, this process is slow in part because of regulation that minimizes expression of these genes in the absence of antibiotics. This suggests that if it were possible to turn on their expression, the cost would increase, thereby accelerating removal of resistant strains. Experimental and theoretical studies have shown that environmental chemicals can change the fitness cost associated with resistance and therefore have a significant impact on population dynamics. The multiple antibiotic resistance activator (MarA) is a clinically important regulator in Escherichia coli that activates downstream genes to increase resistance against multiple classes of antibiotics. Salicylate is an inducer of MarA that can be found in the environment and derepresses marA's expression. In this study, we sought to unravel the interplay between salicylate and the fitness cost of MarA-mediated antibiotic resistance. Using salicylate as an inducer of MarA, we found that a wide spectrum of concentrations can increase burden in resistant strains compared to susceptible strains. Induction resulted in rapid exclusion of resistant bacteria from mixed populations of antibiotic-resistant and susceptible cells. A mathematical model captures the process and predicts its effect in various environmental conditions. Our work provides a quantitative understanding of salicylate exposure on the fitness of different MarA variants and suggests that salicylate can lead to selection against MarA-mediated resistant strains. More generally, our findings show that natural inducers may serve to bias population membership and could impact antibiotic resistance and other important phenotypes.
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Affiliation(s)
- Tiebin Wang
- Molecular Biology, Cell Biology & Biochemistry Program, Boston University, Boston, Massachusetts; Biological Design Center, Boston University, Boston, Massachusetts
| | - Colin Kunze
- Biological Design Center, Boston University, Boston, Massachusetts; Department of Biomedical Engineering, Boston University, Boston, Massachusetts
| | - Mary J Dunlop
- Molecular Biology, Cell Biology & Biochemistry Program, Boston University, Boston, Massachusetts; Biological Design Center, Boston University, Boston, Massachusetts; Department of Biomedical Engineering, Boston University, Boston, Massachusetts.
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Santamaría-Hernando S, Senovilla M, González-Mula A, Martínez-García PM, Nebreda S, Rodríguez-Palenzuela P, López-Solanilla E, Rodríguez-Herva JJ. The Pseudomonas syringae pv. tomato DC3000 PSPTO_0820 multidrug transporter is involved in resistance to plant antimicrobials and bacterial survival during tomato plant infection. PLoS One 2019; 14:e0218815. [PMID: 31237890 PMCID: PMC6592562 DOI: 10.1371/journal.pone.0218815] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Accepted: 06/10/2019] [Indexed: 01/25/2023] Open
Abstract
Multidrug resistance efflux pumps protect bacterial cells against a wide spectrum of antimicrobial compounds. PSPTO_0820 is a predicted multidrug transporter from the phytopathogenic bacterium Pseudomonas syringae pv. tomato DC3000. Orthologs of this protein are conserved within many Pseudomonas species that interact with plants. To study the potential role of PSPTO_0820 in plant-bacteria interaction, a mutant in this gene was isolated and characterized. In addition, with the aim to find the outer membrane channel for this efflux system, a mutant in PSPTO_4977, a TolC-like gene, was also analyzed. Both mutants were more susceptible to trans-cinnamic and chlorogenic acids and to the flavonoid (+)-catechin, when added to the culture medium. The expression level of both genes increased in the presence of (+)-catechin and, in the case of PSPTO_0820, also in response to trans-cinnamic acid. PSPTO_0820 and PSPTO_4977 mutants were unable to colonize tomato at high population levels. This work evidences the involvement of these two proteins in the resistance to plant antimicrobials, supporting also the importance of chlorogenic acid, trans-cinnamic acid, and (+)-catechin in the tomato plant defense response against P. syringae pv. tomato DC3000 infection.
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Affiliation(s)
- Saray Santamaría-Hernando
- Centro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Pozuelo de Alarcón, Madrid, Spain
| | - Marta Senovilla
- Centro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Pozuelo de Alarcón, Madrid, Spain
| | - Almudena González-Mula
- Centro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Pozuelo de Alarcón, Madrid, Spain
| | - Pedro Manuel Martínez-García
- Centro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Pozuelo de Alarcón, Madrid, Spain
| | - Sandra Nebreda
- Centro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Pozuelo de Alarcón, Madrid, Spain
| | - Pablo Rodríguez-Palenzuela
- Centro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Pozuelo de Alarcón, Madrid, Spain
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, Madrid, Spain
| | - Emilia López-Solanilla
- Centro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Pozuelo de Alarcón, Madrid, Spain
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, Madrid, Spain
| | - José Juan Rodríguez-Herva
- Centro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Pozuelo de Alarcón, Madrid, Spain
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, Madrid, Spain
- * E-mail:
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Palmer AC, Chait R, Kishony R. Nonoptimal Gene Expression Creates Latent Potential for Antibiotic Resistance. Mol Biol Evol 2019; 35:2669-2684. [PMID: 30169679 PMCID: PMC6231494 DOI: 10.1093/molbev/msy163] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Bacteria regulate genes to survive antibiotic stress, but regulation can be far from perfect. When regulation is not optimal, mutations that change gene expression can contribute to antibiotic resistance. It is not systematically understood to what extent natural gene regulation is or is not optimal for distinct antibiotics, and how changes in expression of specific genes quantitatively affect antibiotic resistance. Here we discover a simple quantitative relation between fitness, gene expression, and antibiotic potency, which rationalizes our observation that a multitude of genes and even innate antibiotic defense mechanisms have expression that is critically nonoptimal under antibiotic treatment. First, we developed a pooled-strain drug-diffusion assay and screened Escherichia coli overexpression and knockout libraries, finding that resistance to a range of 31 antibiotics could result from changing expression of a large and functionally diverse set of genes, in a primarily but not exclusively drug-specific manner. Second, by synthetically controlling the expression of single-drug and multidrug resistance genes, we observed that their fitness–expression functions changed dramatically under antibiotic treatment in accordance with a log-sensitivity relation. Thus, because many genes are nonoptimally expressed under antibiotic treatment, many regulatory mutations can contribute to resistance by altering expression and by activating latent defenses.
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Affiliation(s)
- Adam C Palmer
- Department of Systems Biology, Harvard Medical School, Boston, MA.,Laboratory of Systems Pharmacology, Harvard Medical School, Boston, MA
| | - Remy Chait
- Department of Systems Biology, Harvard Medical School, Boston, MA.,Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Roy Kishony
- Department of Systems Biology, Harvard Medical School, Boston, MA.,Departments of Biology and Computer Science, Technion-Israel Institute of Technology, Haifa, Israel
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Laudy AE. Non-antibiotics, Efflux Pumps and Drug Resistance of Gram-negative Rods. Pol J Microbiol 2019; 67:129-135. [PMID: 30015451 PMCID: PMC7256865 DOI: 10.21307/pjm-2018-017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2018] [Indexed: 01/27/2023] Open
Abstract
Non-antibiotic medicinal products consist of drugs with diverse activity against bacteria. Many non-antibiotics demonstrate direct anti-bacterial activity against Gram-positive cocci. The activity observed against Gram-negative rods is much lower and non-antibiotics primarily from the following groups: non-steroidal anti-inflammatory drugs, cardiovascular and antidepressant medicinal products demonstrate this activity. It has been shown that the low activity of some non-antibiotics or the absence of activity against Gram-negative rods is related, among other things, to the extrusion of these compounds from bacterial cells by multi-drug resistance efflux pumps. Substrates for the resistance-nodulation-division efflux systems include the following non-antibiotics: salicylate, diclofenac, ibuprofen, mefenamic acid, naproxen, amitriptyline, alendronate sodium, nicergoline, and ticlopidine. In addition, interactions between non-antibiotics and multi-drug resistance efflux pumps have been observed. It has also been revealed that depending on the concentration, salicylate induces expression of multi-drug resistance efflux pumps in Escherichia coli, Salmonella enterica subsp. enterica serotype Typhimurium, and Burkholderia cenocepacia. However, salicylate does not affect the expression of the resistance-nodulation-division efflux systems in Stenotrophomonas maltophilia and Acinetobacter baumannii. Most importantly, there were no effects of medicinal products containing some non-antibiotic active substances, except salicylate, as substrates of multi-drug resistance efflux pumps, on the induction of Gram-negative rod resistance to quinolones.
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Affiliation(s)
- Agnieszka Ewa Laudy
- Department of Pharmaceutical Microbiology, Medical University of Warsaw,Warsaw,Poland
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Davies R, Wales A. Antimicrobial Resistance on Farms: A Review Including Biosecurity and the Potential Role of Disinfectants in Resistance Selection. Compr Rev Food Sci Food Saf 2019; 18:753-774. [PMID: 33336931 DOI: 10.1111/1541-4337.12438] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/04/2019] [Accepted: 02/05/2019] [Indexed: 12/11/2022]
Abstract
Resistance to therapeutic antimicrobial agents is recognized as a growing problem for both human and veterinary medicine, and the need to address the issue in both of these linked domains is a current priority in public policy. Efforts to limit antimicrobial resistance (AMR) on farms have so far focused on control of the supply and use of antimicrobial drugs, plus husbandry measures to reduce infectious disease. In the United Kingdom and some other countries, substantial progress has been made recently against targets on agricultural antimicrobial drug use. However, evidence suggests that resistant pathogenic and commensal bacteria can persist and spread within and between premises despite declining or zero antimicrobial drug use. Reasons for this are likely complex and varied but may include: bacterial adaptations to ameliorate fitness costs associated with maintenance and replication of resistance genes and associated proteins, horizontal transmission of genetic resistance determinants between bacteria, physical transfer of bacteria via movement (of animals, workers, and equipment), ineffective cleaning and disinfection, and co-selection of resistance to certain drugs by use of other antimicrobials, heavy metals, or biocides. Areas of particular concern for public health include extended-spectrum cephalosporinases and fluoroquinolone resistance among Enterobacteriaceae, livestock-associated methicillin-resistant Staphylococcus aureus, and the emergence of transmissible colistin resistance. Aspects of biosecurity have repeatedly been identified as risk factors for the presence of AMR on farm premises, but there are large gaps in our understanding of the most important risk factors and the most effective interventions. The present review aims to summarize the present state of knowledge in this area, from a European perspective.
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Affiliation(s)
- Robert Davies
- Bacteriology and Food Safety Dept., Animal and Plant Health Agency (APHA - Weybridge), Woodham Lane, New Haw, Addlestone, KT15 3NB, UK
| | - Andrew Wales
- Pathology and Infectious Diseases Dept., School of Veterinary Medicine, Faculty of Health and Medical Sciences, Vet School Main Building, Daphne Jackson Rd., Univ. of Surrey, Guildford, GU2 7AL, UK
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Selenocompounds as Novel Antibacterial Agents and Bacterial Efflux Pump Inhibitors. Molecules 2019; 24:molecules24081487. [PMID: 31014009 PMCID: PMC6514980 DOI: 10.3390/molecules24081487] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/02/2019] [Accepted: 04/13/2019] [Indexed: 11/17/2022] Open
Abstract
Bacterial multidrug resistance is becoming a growing problem for public health, due to the development and spreading of bacterial strains resistant to antimicrobials. In this study, the antibacterial and multidrug resistance reversing activity of a series of seleno-carbonyl compounds has been evaluated. The effects of eleven selenocompounds on bacterial growth were evaluated in Staphylococcus aureus, methicillin resistant S. aureus (MRSA), Enterococcus faecalis, Escherichia coli, and Chlamydia trachomatis D. The combination effect of compounds with antibiotics was examined by the minimum inhibitory concentration reduction assay. Their efflux pump (EP) inhibitory properties were assessed using real-time fluorimetry. Relative expressions of EP and quorum-sensing genes were studied by quantitative PCR. Results showed that a methylketone selenoester had remarkable antibacterial activity against Gram-positive bacteria and potentiated the activity of oxacillin in MRSA. Most of the selenocompounds showed significant anti-chlamydial effects. The selenoanhydride and the diselenodiester were active inhibitors of the AcrAB-TolC system. Based on these results it can be concluded that this group of selenocompounds can be attractive potential antibacterials and EP inhibitors. The discovery of new derivatives with a significant antibacterial activity as novel selenocompounds, is of high impact in the fight against resistant pathogens.
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Abstract
![]()
The biotechnological revolution has made it
possible to create
enzymes for many reactions by directed evolution. However, because
of the immense number of possibilities, the availability of enzymes
that possess a basal level of the desired catalytic activity is a
prerequisite for success. For new-to-nature reactions, artificial
metalloenzymes (ARMs), which are rationally designed hybrids of proteins
and catalytically active transition-metal complexes, can be such a
starting point. This Account details our efforts toward the
creation of ARMs for
the catalysis of new-to-nature reactions. Key to our approach is the
notion that the binding of substrates, that is, effective molarity,
is a key component to achieving large accelerations in catalysis.
For this reason, our designs are based on the multidrug resistance
regulator LmrR, a dimeric transcription factor with a large, hydrophobic
binding pocket at its dimer interface. In this pocket, there are two
tryptophan moieties, which are important for promiscuous binding of
planar hydrophobic conjugated compounds by π-stacking. The catalytic
machinery is introduced either by the covalent linkage of a catalytically
active metal complex or via the ligand or supramolecular assembly,
taking advantage of the two central tryptophan moieties for noncovalent
binding of transition-metal complexes. Designs based on the
chemical modification of LmrR were successful
in catalysis, but this approach proved too laborious to be practical.
Therefore, expanded genetic code methodologies were used to introduce
metal binding unnatural amino acids during LmrR biosynthesis in vivo.
These ARMs have been successfully applied in Cu(II) catalyzed Friedel–Crafts
alkylation of indoles. The extension to MDRs from the TetR family
resulted in ARMs capable of providing the opposite enantiomer of the
Friedel–Crafts product. We have employed a computationally
assisted redesign of these ARMs to create a more active and selective
artificial hydratase, introducing a glutamate as a general base at
a judicious position so it can activate and direct the incoming water
nucleophile. A supramolecularly assembled ARM from LmrR and
copper(II)–phenanthroline
was successful in Friedel–Crafts alkylation reactions, giving
rise to up to 94% ee. Also, hemin was bound, resulting in an artificial
heme enzyme for enantioselective cyclopropanation reactions. The importance
of structural dynamics of LmrR was suggested by computational studies,
which showed that the pore can open up to allow access of substrates
to the catalytic iron center, which, according to the crystal structure,
is deeply buried inside the protein. Finally, the assembly approaches
were combined to introduce both
a catalytic and a regulatory domain, resulting in an ARM that was
specifically activated in the presence of Fe(II) salts but not Zn(II)
salts. Our work demonstrates that LmrR is a privileged scaffold
for ARM
design: It allows for multiple assembly methods and even combinations
of these, it can be applied in a variety of different catalytic reactions,
and it shows significant structural dynamics that contribute to achieving
the desired catalytic activity. Moreover, both the creation via expanded
genetic code methods as well as the supramolecular assembly make LmrR-based
ARMs highly suitable for achieving the ultimate goal of the integration
of ARMs in biosynthetic pathways in vivo to create a hybrid metabolism.
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Affiliation(s)
- Gerard Roelfes
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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Seoane P, Tapia-Paniagua ST, Bautista R, Alcaide E, Esteve C, Martínez-Manzanares E, Balebona MC, Claros MG, Moriñigo MA. TarSynFlow, a workflow for bacterial genome comparisons that revealed genes putatively involved in the probiotic character of Shewanella putrefaciens strain Pdp11. PeerJ 2019; 7:e6526. [PMID: 30842906 PMCID: PMC6397758 DOI: 10.7717/peerj.6526] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 01/26/2019] [Indexed: 11/20/2022] Open
Abstract
Probiotic microorganisms are of great interest in clinical, livestock and aquaculture. Knowledge of the genomic basis of probiotic characteristics can be a useful tool to understand why some strains can be pathogenic while others are probiotic in the same species. An automatized workflow called TarSynFlow (Targeted Synteny Workflow) has been then developed to compare finished or draft bacterial genomes based on a set of proteins. When used to analyze the finished genome of the probiotic strain Pdp11 of Shewanella putrefaciens and genome drafts from seven known non-probiotic strains of the same species obtained in this work, 15 genes were found exclusive of Pdp11. Their presence was confirmed by PCR using Pdp11-specific primers. Functional inspection of the 15 genes allowed us to hypothesize that Pdp11 underwent genome rearrangements spurred by plasmids and mobile elements. As a result, Pdp11 presents specific proteins for gut colonization, bile salt resistance and gut pathogen adhesion inhibition, which can explain some probiotic features of Pdp11.
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Affiliation(s)
- Pedro Seoane
- Department of Molecular Biology and Biochemistry, Universidad de Málaga, Málaga, Spain
| | | | - Rocío Bautista
- Andalusian Platform for Bioinformatics, Universidad de Málaga, Málaga, Spain
| | - Elena Alcaide
- Department of Microbiology and Ecology, Universidad de Valencia, Valencia, Spain
| | - Consuelo Esteve
- Department of Microbiology and Ecology, Universidad de Valencia, Valencia, Spain
| | | | | | - M. Gonzalo Claros
- Department of Molecular Biology and Biochemistry, Universidad de Málaga, Málaga, Spain
- Andalusian Platform for Bioinformatics, Universidad de Málaga, Málaga, Spain
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Spatiotemporal expression of the putative MdtABC efflux pump of Phtotorhabdus luminescens occurs in a protease-dependent manner during insect infection. PLoS One 2019; 14:e0212077. [PMID: 30763358 PMCID: PMC6375597 DOI: 10.1371/journal.pone.0212077] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Accepted: 01/25/2019] [Indexed: 11/19/2022] Open
Abstract
Photorhabdus luminescens is an enterobacterium establishing a mutualistic symbiosis with nematodes, that also kills insects after septicaemia and connective tissue colonization. The role of the bacterial mdtABC genes encoding a putative multidrug efflux system from the resistance/nodulation/cell division family was investigated. We showed that a mdtA mutant and the wild type had similar levels of resistance to antibiotics, antimicrobial peptides, metals, detergents and bile salts. The mdtA mutant was also as pathogenic as the wild-type following intrahaemocoel injection in Locusta migratoria, but had a slightly attenuated phenotype in Spodoptera littoralis. A transcriptional fusion of the mdtA promoter (PmdtA) and the green fluorescent protein (gfp) encoding gene was induced by copper in bacteria cultured in vitro. The PmdtA-gfp fusion was strongly induced within bacterial aggregates in the haematopoietic organ during late stages of infection in L. migratoria, whereas it was only weakly expressed in insect plasma throughout infection. A medium supplemented with haematopoietic organ extracts induced the PmdtA-gfp fusion ex vivo, suggesting that site-specific mdtABC expression resulted from insect signals from the haematopoietic organ. Finally, we showed that protease inhibitors abolished ex vivo activity of the PmdtA-gfp fusion in the presence of haematopoietic organ extracts, suggesting that proteolysis by-products play a key role in upregulating the putative MdtABC efflux pump during insect infection with P. luminescens.
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Xu Q, Zhai Z, An H, Yang Y, Yin J, Wang G, Ren F, Hao Y. The MarR Family Regulator BmrR Is Involved in Bile Tolerance of Bifidobacterium longum BBMN68 via Controlling the Expression of an ABC Transporter. Appl Environ Microbiol 2019; 85:e02453-18. [PMID: 30478236 PMCID: PMC6344635 DOI: 10.1128/aem.02453-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 11/15/2018] [Indexed: 11/20/2022] Open
Abstract
In order to colonize the human gastrointestinal tract and exert their beneficial effects, bifidobacteria must effectively cope with toxic bile salts in the intestine; however, the molecular mechanism underlying bile tolerance is poorly understood. In this study, heterologous expression of a MarR family transcriptional regulator, BmrR, significantly reduced the ox bile resistance of Lactococcus lactis NZ9000, suggesting that BmrR might play a role in the bile stress response. In silico analysis combined with reverse transcription-PCR assays demonstrated that bmrR was cotranscribed with bmrA and bmrB, which encoded multidrug resistance (MDR) ABC transporters. Promoter prediction and electrophoretic mobility shift assays revealed that BmrR could autoregulate the bmrRAB operon by binding to the bmr box (ATTGTTG-6nt-CAACAAT) in the promoter region. Moreover, heterologous expression of bmrA and bmrB in L. lactis yielded 20.77-fold higher tolerance to 0.10% ox bile, compared to the wild-type strain. In addition, ox bile could disrupt the DNA binding activity of BmrR as a ligand. Taken together, our findings indicate that the bmrRAB operon is autoregulated by the transcriptional regulator BmrR and ox bile serves as an inducer to activate the bile efflux transporter BmrAB in response to bile stress in Bifidobacterium longum BBMN68.IMPORTANCE Bifidobacteria are natural inhabitants of the human intestinal tract. Some bifidobacterial strains are used as probiotics in fermented dairy production because of their health-promoting effects. Following consumption, bifidobacteria colonize the lower intestinal tract, where the concentrations of bile salts remain nearly 0.05% to 2.0%. Bile salts, as detergent-like antimicrobial compounds, can cause cellular membrane disruption, protein misfolding, and DNA damage. Therefore, tolerance to physiological bile stress is indeed essential for bifidobacteria to survive and to exert probiotic effects in the gastrointestinal tract. In B. longum BBMN68, the MarR-type regulator BmrR was involved in the bile stress response by autoregulating the bmrRAB operon, and ox bile as an inducer could increase the expression of the BmrAB transporter to enhance the bile tolerance of BBMN68. Our study represents a functional analysis of the bmrRAB operon in the bile stress response, which will provide new insights into bile tolerance mechanisms in Bifidobacterium and other bacteria.
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Affiliation(s)
- Qi Xu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Zhengyuan Zhai
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
- Department of Food Science and Technology, University of California, Davis, Davis, California, USA
| | - Haoran An
- Center for Infectious Disease Research, Tsinghua-Peking Joint Center for Life Science, School of Medicine, Tsinghua University, Beijing, China
| | - Yang Yang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Jia Yin
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Guohong Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Fazheng Ren
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
- Key Laboratory of Functional Dairy, Beijing, China
| | - Yanling Hao
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
- Key Laboratory of Functional Dairy, Beijing, China
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Zhao Y, Wu BH, Liu ZN, Qiao J, Zhao GR. Combinatorial Optimization of Resveratrol Production in Engineered E. coli. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:13444-13453. [PMID: 30488696 DOI: 10.1021/acs.jafc.8b05014] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Resveratrol, a plant-derived polyphenolic compound with various health activities, is widely used in nutraceutical and food additives. Herein, combinatorial optimization of resveratrol biosynthetic pathway and intracellular environment of E. coli was carried out. By screening pathway genes from various species and exploring their expression pattern, we initially constructed resveratrol-producing strains. Further targeting at availability of malonyl-CoA through expressing ACC of Corynebacterium glutamicum and antisense inhibiting native fabD significantly increased resveratrol biosynthesis. Transport engineering for resveratrol secretion and molecular chaperones helping for folding heterologous enzymes were employed to improve the intracellular environments in remarkable degrees. By introducing PcTAL of Phanerochaete chrysosporium and tuning expression model of PcTAL, At4CL, and VvSTS, an engineered E. coli produced 57.77 mg/L of resveratrol from l-tyrosine. After integrating the above strategies, resveratrol titer reached to 238.71 mg/L from l-tyrosine. The combinatorial optimization in this study provides a promising strategy to produce valuable natural products in heterologous expression systems.
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Affiliation(s)
- Ying Zhao
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology , Tianjin University , Tianjin 300350 , China
- Key Laboratory of Systems Bioengineering , Ministry of Education , Tianjin 300350 , China
- SynBio Research Platform , Collaborative Innovation Center of Chemical Science and Engineering , Tianjin 300350 , China
| | - Bi-Han Wu
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology , Tianjin University , Tianjin 300350 , China
- Key Laboratory of Systems Bioengineering , Ministry of Education , Tianjin 300350 , China
- SynBio Research Platform , Collaborative Innovation Center of Chemical Science and Engineering , Tianjin 300350 , China
| | - Zhen-Ning Liu
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology , Tianjin University , Tianjin 300350 , China
- Key Laboratory of Systems Bioengineering , Ministry of Education , Tianjin 300350 , China
- SynBio Research Platform , Collaborative Innovation Center of Chemical Science and Engineering , Tianjin 300350 , China
| | - Jianjun Qiao
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology , Tianjin University , Tianjin 300350 , China
- Key Laboratory of Systems Bioengineering , Ministry of Education , Tianjin 300350 , China
- SynBio Research Platform , Collaborative Innovation Center of Chemical Science and Engineering , Tianjin 300350 , China
| | - Guang-Rong Zhao
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology , Tianjin University , Tianjin 300350 , China
- Key Laboratory of Systems Bioengineering , Ministry of Education , Tianjin 300350 , China
- SynBio Research Platform , Collaborative Innovation Center of Chemical Science and Engineering , Tianjin 300350 , China
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Shriram V, Khare T, Bhagwat R, Shukla R, Kumar V. Inhibiting Bacterial Drug Efflux Pumps via Phyto-Therapeutics to Combat Threatening Antimicrobial Resistance. Front Microbiol 2018; 9:2990. [PMID: 30619113 PMCID: PMC6295477 DOI: 10.3389/fmicb.2018.02990] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 11/19/2018] [Indexed: 12/04/2022] Open
Abstract
Antibiotics, once considered the lifeline for treating bacterial infections, are under threat due to the emergence of threatening antimicrobial resistance (AMR). These drug-resistant microbes (or superbugs) are non-responsive to most of the commonly used antibiotics leaving us with few treatment options and escalating mortality-rates and treatment costs. The problem is further aggravated by the drying-pipeline of new and potent antibiotics effective particularly against the drug-resistant strains. Multidrug efflux pumps (EPs) are established as principal determinants of AMR, extruding multiple antibiotics out of the cell, mostly in non-specific manner and have therefore emerged as potent drug-targets for combating AMR. Plants being the reservoir of bioactive compounds can serve as a source of potent EP inhibitors (EPIs). The phyto-therapeutics with noteworthy drug-resistance-reversal or re-sensitizing activities may prove significant for reviving the otherwise fading antibiotics arsenal and making this combination-therapy effective. Contemporary attempts to potentiate the antibiotics with plant extracts and pure phytomolecules have gained momentum though with relatively less success against Gram-negative bacteria. Plant-based EPIs hold promise as potent drug-leads to combat the EPI-mediated AMR. This review presents an account of major bacterial multidrug EPs, their roles in imparting AMR, effective strategies for inhibiting drug EPs with phytomolecules, and current account of research on developing novel and potent plant-based EPIs for reversing their AMR characteristics. Recent developments including emergence of in silico tools, major success stories, challenges and future prospects are also discussed.
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Affiliation(s)
- Varsha Shriram
- Department of Botany, Prof. Ramkrishna More College, Savitribai Phule Pune University, Pune, India
| | - Tushar Khare
- Department of Biotechnology, Modern College of Arts, Science and Commerce (Savitribai Phule Pune University), Pune, India
| | - Rohit Bhagwat
- Department of Environmental Science, Savitribai Phule Pune University, Pune, India
| | - Ravi Shukla
- Centre for Advanced Materials and Industrial Chemistry, School of Science, RMIT University, Melbourne, VIC, Australia
| | - Vinay Kumar
- Department of Biotechnology, Modern College of Arts, Science and Commerce (Savitribai Phule Pune University), Pune, India.,Department of Environmental Science, Savitribai Phule Pune University, Pune, India
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