1
|
Hussain A, Ong EBB, Balaram P, Ismail A, Kien PK. TolC facilitates the intracellular survival and immunomodulation of Salmonella Typhi in human host cells. Virulence 2024; 15:2395831. [PMID: 39185619 PMCID: PMC11385165 DOI: 10.1080/21505594.2024.2395831] [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: 01/30/2024] [Revised: 06/29/2024] [Accepted: 08/19/2024] [Indexed: 08/27/2024] Open
Abstract
Salmonella enterica serovar Typhi (S. Typhi) causes typhoid fever, a systemic infection that affects millions of people worldwide. S. Typhi can invade and survive within host cells, such as intestinal epithelial cells and macrophages, by modulating their immune responses. However, the immunomodulatory capability of S. Typhi in relation to TolC-facilitated efflux pump function remains unclear. The role of TolC, an outer membrane protein that facilitates efflux pump function, in the invasion and immunomodulation of S. Typhi, was studied in human intestinal epithelial cells and macrophages. The tolC deletion mutant of S. Typhi was compared with the wild-type and its complemented strain in terms of their ability to invade epithelial cells, survive and induce cytotoxicity in macrophages, and elicit proinflammatory cytokine production in macrophages. The tolC mutant, which has a defective outer membrane, was impaired in invading epithelial cells compared to the wild-type strain, but the intracellular presence of the tolC mutant exhibited greater cytotoxicity and induced higher levels of proinflammatory cytokines (IL-1β and IL-8) in macrophages compared to the wild-type strain. These effects were reversed by complementing the tolC mutant with a functional tolC gene. Our results suggest that TolC plays a role in S. Typhi to efficiently invade epithelial cells and suppress host immune responses during infection. TolC may be a potential target for the development of novel therapeutics against typhoid fever.
Collapse
Affiliation(s)
- Ashraf Hussain
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, Penang, Malaysia
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL USA
| | - Eugene Boon Beng Ong
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, Penang, Malaysia
| | - Prabha Balaram
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, Penang, Malaysia
| | - Asma Ismail
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, Penang, Malaysia
| | - Phua Kia Kien
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, Penang, Malaysia
| |
Collapse
|
2
|
Whittle EE, Orababa O, Osgerby A, Siasat P, Element SJ, Blair JMA, Overton TW. Efflux pumps mediate changes to fundamental bacterial physiology via membrane potential. mBio 2024:e0237024. [PMID: 39248573 DOI: 10.1128/mbio.02370-24] [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: 08/09/2024] [Accepted: 08/15/2024] [Indexed: 09/10/2024] Open
Abstract
Efflux pumps are well known to be an important mechanism for removing noxious substances such as antibiotics from bacteria. Given that many antibiotics function by accumulating inside bacteria, efflux pumps contribute to resistance. Efflux pump inactivation is a potential strategy to combat antimicrobial resistance, as bacteria would not be able to pump out antibiotics. We recently discovered that the impact of loss of efflux function is only apparent in actively growing cells. We demonstrated that the global transcriptome of Salmonella Typhimurium is drastically altered during slower growth leading to stationary-phase cells having a remodeled, less permeable envelope that prevents antibiotics entering the cell. Here, we investigated the effects of deleting the major efflux pump of Salmonella Typhimurium, AcrB, on global gene transcription across growth. We revealed that an acrB knockout entered stationary phase later than the wild-type strain SL1344 and displayed increased and prolonged expression of genes responsible for anaerobic energy metabolism. We devised a model linking efflux and membrane potential, whereby deactivation of AcrB prevents influx of protons across the inner membrane and thereby hyperpolarization. Knockout or deactivation of AcrB was demonstrated to increase membrane potential. We propose that the global transcription regulator ArcBA senses changes to the redox state of the quinol pool (linked to the membrane potential of the bacterium) and coordinates the shift from exponential to stationary phase via the key master regulators RpoS, Rsd, and Rmf. Inactivation of efflux pumps therefore influences the fundamental physiology of Salmonella, with likely impacts on multiple phenotypes.IMPORTANCEWe demonstrate for the first time that deactivation of efflux pumps brings about changes to gross bacterial physiology and metabolism. Rather than simply being a response to noxious substances, efflux pumps appear to play a key role in maintenance of membrane potential and thereby energy metabolism. This discovery suggests that efflux pump inhibition or inactivation might have unforeseen positive consequences on antibiotic activity. Given that stationary-phase bacteria are more resistant to antibiotic uptake, late entry into stationary phase would prolong antibiotic accumulation by bacteria. Furthermore, membrane hyperpolarization could result in increased generation of reactive species proposed to be important for the activity of some antibiotics. Finally, changes in gross physiology could also explain the decreased virulence of efflux mutants.
Collapse
Affiliation(s)
- Emily E Whittle
- Department of Microbes, Infection and Microbiomes, Institute of Microbiology and Infection, College of Medical and Dental Sciences, Birmingham, United Kingdom
| | - Oluwatosin Orababa
- Department of Microbes, Infection and Microbiomes, Institute of Microbiology and Infection, College of Medical and Dental Sciences, Birmingham, United Kingdom
| | - Alexander Osgerby
- School of Chemical Engineering, University of Birmingham, Birmingham, United Kingdom
| | - Pauline Siasat
- Department of Microbes, Infection and Microbiomes, Institute of Microbiology and Infection, College of Medical and Dental Sciences, Birmingham, United Kingdom
| | - Sarah J Element
- Department of Microbes, Infection and Microbiomes, Institute of Microbiology and Infection, College of Medical and Dental Sciences, Birmingham, United Kingdom
| | - Jessica M A Blair
- Department of Microbes, Infection and Microbiomes, Institute of Microbiology and Infection, College of Medical and Dental Sciences, Birmingham, United Kingdom
| | - Tim W Overton
- School of Chemical Engineering, University of Birmingham, Birmingham, United Kingdom
| |
Collapse
|
3
|
Dulanto Chiang A, Dekker JP. Efflux pump-mediated resistance to new beta lactam antibiotics in multidrug-resistant gram-negative bacteria. COMMUNICATIONS MEDICINE 2024; 4:170. [PMID: 39210044 PMCID: PMC11362173 DOI: 10.1038/s43856-024-00591-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 08/14/2024] [Indexed: 09/04/2024] Open
Abstract
The emergence and spread of bacteria resistant to commonly used antibiotics poses a critical threat to modern medical practice. Multiple classes of bacterial efflux pump systems play various roles in antibiotic resistance, and members of the resistance-nodulation-division (RND) transporter superfamily are among the most important determinants of efflux-mediated resistance in gram-negative bacteria. RND pumps demonstrate broad substrate specificities, facilitating extrusion of multiple chemical classes of antibiotics from the bacterial cell. Several newer beta-lactams and beta-lactam/beta-lactamase inhibitor combinations (BL/BLI) have been developed to treat infections caused by multidrug resistant bacteria. Here we review recent studies that suggest RND efflux pumps in clinically relevant gram-negative bacteria may play critical but underappreciated roles in the development of resistance to beta-lactams and novel BL/BLI combinations. Improved understanding of the genetic and structural basis of RND efflux pump-mediated resistance may identify new antibiotic targets as well as strategies to minimize the emergence of resistance.
Collapse
Affiliation(s)
- Augusto Dulanto Chiang
- Laboratory of Clinical Immunology and Microbiology, NIAID, NIH, Bethesda, MD, USA
- Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN, 37232, USA
| | - John P Dekker
- Laboratory of Clinical Immunology and Microbiology, NIAID, NIH, Bethesda, MD, USA.
- National Institutes of Health Clinical Center, NIH, Bethesda, MD, USA.
| |
Collapse
|
4
|
Duffey M, Jumde RP, da Costa RM, Ropponen HK, Blasco B, Piddock LJ. Extending the Potency and Lifespan of Antibiotics: Inhibitors of Gram-Negative Bacterial Efflux Pumps. ACS Infect Dis 2024; 10:1458-1482. [PMID: 38661541 PMCID: PMC11091901 DOI: 10.1021/acsinfecdis.4c00091] [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: 02/02/2024] [Revised: 03/14/2024] [Accepted: 03/20/2024] [Indexed: 04/26/2024]
Abstract
Efflux is a natural process found in all prokaryotic and eukaryotic cells that removes a diverse range of substrates from inside to outside. Many antibiotics are substrates of bacterial efflux pumps, and modifications to the structure or overexpression of efflux pumps are an important resistance mechanism utilized by many multidrug-resistant bacteria. Therefore, chemical inhibition of bacterial efflux to revitalize existing antibiotics has been considered a promising approach for antimicrobial chemotherapy over two decades, and various strategies have been employed. In this review, we provide an overview of bacterial multidrug resistance (MDR) efflux pumps, of which the resistance nodulation division (RND) efflux pumps are considered the most clinically relevant in Gram-negative bacteria, and describe over 50 efflux inhibitors that target such systems. Although numerous efflux inhibitors have been identified to date, none have progressed into clinical use because of formulation, toxicity, and pharmacokinetic issues or a narrow spectrum of inhibition. For these reasons, the development of efflux inhibitors has been considered a difficult and complex area of research, and few active preclinical studies on efflux inhibitors are in progress. However, recently developed tools, including but not limited to computational tools including molecular docking models, offer hope that further research on efflux inhibitors can be a platform for research and development of new bacterial efflux inhibitors.
Collapse
Affiliation(s)
- Maëlle Duffey
- Global
Antibiotic Research & Development Partnership (GARDP), Chemin Camille-Vidart 15, 1202 Geneva, Switzerland
| | - Ravindra P. Jumde
- Global
Antibiotic Research & Development Partnership (GARDP), Chemin Camille-Vidart 15, 1202 Geneva, Switzerland
| | - Renata M.A. da Costa
- Global
Antibiotic Research & Development Partnership (GARDP), Chemin Camille-Vidart 15, 1202 Geneva, Switzerland
| | - Henni-Karoliina Ropponen
- Global
Antibiotic Research & Development Partnership (GARDP), Chemin Camille-Vidart 15, 1202 Geneva, Switzerland
| | - Benjamin Blasco
- Global
Antibiotic Research & Development Partnership (GARDP), Chemin Camille-Vidart 15, 1202 Geneva, Switzerland
| | - Laura J.V. Piddock
- Global
Antibiotic Research & Development Partnership (GARDP), Chemin Camille-Vidart 15, 1202 Geneva, Switzerland
| |
Collapse
|
5
|
Wilhelm J, Pos KM. Molecular insights into the determinants of substrate specificity and efflux inhibition of the RND efflux pumps AcrB and AdeB. MICROBIOLOGY (READING, ENGLAND) 2024; 170:001438. [PMID: 38358391 PMCID: PMC10924465 DOI: 10.1099/mic.0.001438] [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: 11/01/2022] [Accepted: 01/30/2024] [Indexed: 02/16/2024]
Abstract
Gram-negative bacterial members of the Resistance Nodulation and cell Division (RND) superfamily form tripartite efflux pump systems that span the cell envelope. One of the intriguing features of the multiple drug efflux members of this superfamily is their ability to recognize different classes of antibiotics, dyes, solvents, bile salts, and detergents. This review provides an overview of the molecular mechanisms of multiple drug efflux catalysed by the tripartite RND efflux system AcrAB-TolC from Eschericha coli. The determinants for sequential or simultaneous multiple substrate binding and efflux pump inhibitor binding are discussed. A comparison is made with the determinants for substrate binding of AdeB from Acinetobacter baumannii, which acts within the AdeABC multidrug efflux system. There is an apparent general similarity between the structures of AcrB and AdeB and their substrate specificity. However, the presence of distinct conformational states and different drug efflux capacities as revealed by single-particle cryo-EM and mutational analysis suggest that the drug binding and transport features exhibited by AcrB may not be directly extrapolated to the homolog AdeB efflux pump.
Collapse
Affiliation(s)
- Julia Wilhelm
- Institute of Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany
| | - Klaas Martinus Pos
- Institute of Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany
| |
Collapse
|
6
|
Song D, Qi X, Huang Y, Jia A, Liang Y, Man C, Yang X, Jiang Y. Comparative proteomics reveals the antibiotic resistance and virulence of Cronobacter isolated from powdered infant formula and its processing environment. Int J Food Microbiol 2023; 407:110374. [PMID: 37678039 DOI: 10.1016/j.ijfoodmicro.2023.110374] [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: 05/26/2023] [Revised: 07/31/2023] [Accepted: 08/29/2023] [Indexed: 09/09/2023]
Abstract
Cronobacter species are opportunistic foodborne pathogens that can cause neonatal meningitis, sepsis, and necrotizing enterocolitis. In this genus, certain level strains have high mortality to infant (Cronobacter sakazakii and Cronobacter malonaticus) and antibiotic tolerance. Cronobacter has strong environmental tolerance (acid resistance, high temperature resistance, UV resistance, antibiotic resistance, etc.) and can survive in a variety of environments. It has been isolated in various production environments and products in several countries. However, the relationships between Cronobacter antibiotic tolerance and virulence remain unclear, especially at the molecular level. In this study, 96 strains of Cronobacter were isolated from powdered infant formula and its processing environment and screened for antibiotic tolerance, and proteomic maps of the representative strains of Cronobacter with antibiotic tolerance were generated by analyzing proteomics data using multiple techniques to identify protein that are implicated in Cronobacter virulence and antibiotic resistance. The increase in antibiotic tolerance of Cronobacter had a certain increase in the production of enterotoxin and hemolysin. Only triple tolerated Cronobacter sakazakii decreased the utilization of sialic acid. A total of 16,131 intracellular proteins were detected in eight representative strains, and different proteomes were present in strains with different antibiotic tolerance, including 56 virulence-related proteins. Multiple virulence proteins regulated by unknown genes were also found in the eight isolated representative strains.
Collapse
Affiliation(s)
- Danliangmin Song
- Department of Food Science, Northeast Agricultural University, Harbin 150038, China
| | - Xuehe Qi
- Department of Food Science, Northeast Agricultural University, Harbin 150038, China.
| | - Yan Huang
- Department of Food Science, Northeast Agricultural University, Harbin 150038, China
| | - Ai Jia
- Department of Food Science, Northeast Agricultural University, Harbin 150038, China
| | - Yaqi Liang
- Department of Food Science, Northeast Agricultural University, Harbin 150038, China
| | - Chaoxin Man
- Key Laboratory of Dairy Science, Ministry of Education, Harbin 150030, China.
| | - Xinyan Yang
- Key Laboratory of Dairy Science, Ministry of Education, Harbin 150030, China.
| | - Yujun Jiang
- Department of Food Science, Northeast Agricultural University, Harbin 150038, China.
| |
Collapse
|
7
|
Ricci V, Kaur J, Stone J, Piddock LJV. Antibiotics do not induce expression of acrAB directly but via a RamA-dependent pathway. Antimicrob Agents Chemother 2023; 67:e0062023. [PMID: 37815378 PMCID: PMC10649046 DOI: 10.1128/aac.00620-23] [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: 05/12/2023] [Accepted: 08/09/2023] [Indexed: 10/11/2023] Open
Abstract
The aim of this study was to determine if acrAB induction in Salmonella Typhimurium relies solely on RamA or if other transcriptional activator pathways are also involved, and to better understand the kinetics of induction of both acrAB and ramA. We evaluated the expression of acrAB in S. Typhimurium in response to a variety of compounds that are known to induce the expression of one or more of the transcriptional activators, MarA, SoxS, RamA, and Rob. We utilized green fluorescent protein (GFP) transcriptional reporter fusions to investigate the changes in the expression of acrAB, ramA, marA, and soxS following exposure to sub-inhibitory concentrations of antimicrobial compounds. Of the compounds tested, 13 induce acrAB expression in S. Typhimurium via RamA, MarA, SoxS, and Rob-dependent pathways. None of the tested antibiotics induced acrAB expression, and compounds that induced acrAB expression also induced a general stress response. The results from this study show that the majority of compounds tested induced acrAB via the RamA-dependent pathway. However, none of the antibiotic substrates of the AcrB efflux pump directly increased the expression of AcrAB either directly or indirectly via the induction of one of the transcriptional activators. Using a dual GFP/RFP reporter, we investigated the kinetics of the induction of ramA and acrAB simultaneously and found that acrAB gene expression was transient compared to ramA gene expression. ramA gene expression increased with time and would remain high or decrease slowly over the course of the experiment indicating that RamA exerts a wider global effect and is not limited to efflux regulation alone.
Collapse
Affiliation(s)
- Vito Ricci
- Antimicrobials Research Group, Institute of Microbiology and Infection, College of Medical and Dental Science, University of Birmingham, Birmingham, United Kingdom
| | - Jaswant Kaur
- Antimicrobials Research Group, Institute of Microbiology and Infection, College of Medical and Dental Science, University of Birmingham, Birmingham, United Kingdom
| | - Jack Stone
- Antimicrobials Research Group, Institute of Microbiology and Infection, College of Medical and Dental Science, University of Birmingham, Birmingham, United Kingdom
| | - Laura J. V. Piddock
- Antimicrobials Research Group, Institute of Microbiology and Infection, College of Medical and Dental Science, University of Birmingham, Birmingham, United Kingdom
| |
Collapse
|
8
|
Song D, Jia A, Qi X, Dong K, Liu S, Man C, Yang X, Jiang Y. Co-culture of Cronobacter sakazakii and Staphylococcus aureus: Explore the influence of mixed biofilm formation and regulation of Cronobacter sakazakii biofilm formation genes. Food Res Int 2023; 173:113457. [PMID: 37803782 DOI: 10.1016/j.foodres.2023.113457] [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: 05/23/2023] [Revised: 09/01/2023] [Accepted: 09/10/2023] [Indexed: 10/08/2023]
Abstract
Bacterial biofilm is a protective matrix composed of metabolites secreted by bacteria that envelop bacteria. By forming a biofilm, bacteria can considerably improve their environmental tolerance. In food-related processing environment, different types of microorganisms are often present in biofilms. The main contaminating strain in the powdered infant formula (PIF) processing environment, Cronobacter sakazakii and Staphylococcus aureus continues to pollute the PIF processing environment after biofilm production. This study selected Cronobacter sakazakii with a weak biofilm-forming ability as one of the test organisms. The coexistence of Cronobacter sakazakii and Staphylococcus aureus on the surface of production equipment was simulated to analyze the interaction. Biofilm formation in the co-culture group was significantly higher than the others. In-depth study of the effect of Staphylococcus aureus on the biofilm formation genes of Cronobacter sakazakii. Results show two bacteria can coexist on the surface of a metal device, forming a more compact hybrid biofilm structure. Under co-culture conditions, S. aureus increased bcsA and fliD expression in Cronobacter sakazakii, whereas decreased bcsC expression. Signaling molecules produced by Staphylococcus aureus (Autoinducer 2) significantly promoted the biofilm formation of Cronobacter sakazakii at the concentration of 0-500 ng/mL (0.099-0.177) and up-regulated the expression of bcsA, filD and flhD genes.
Collapse
Affiliation(s)
- Danliangmin Song
- Department of Food Science, Northeast Agricultural University, Harbin 150038, China.
| | - Ai Jia
- Department of Food Science, Northeast Agricultural University, Harbin 150038, China.
| | - Xuehe Qi
- Department of Food Science, Northeast Agricultural University, Harbin 150038, China.
| | - Kai Dong
- Department of Food Science, Northeast Agricultural University, Harbin 150038, China.
| | - Shiyu Liu
- Department of Food Science, Northeast Agricultural University, Harbin 150038, China.
| | - Chaoxin Man
- Key Laboratory of Dairy Science, Ministry of Education, Harbin 150030, China.
| | - Xinyan Yang
- Key Laboratory of Dairy Science, Ministry of Education, Harbin 150030, China.
| | - Yujun Jiang
- Department of Food Science, Northeast Agricultural University, Harbin 150038, China.
| |
Collapse
|
9
|
Maldonado J, Czarnecka B, Harmon DE, Ruiz C. The multidrug efflux pump regulator AcrR directly represses motility in Escherichia coli. mSphere 2023; 8:e0043023. [PMID: 37787551 PMCID: PMC10597343 DOI: 10.1128/msphere.00430-23] [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: 08/01/2023] [Accepted: 08/18/2023] [Indexed: 10/04/2023] Open
Abstract
Efflux and motility are two key biological functions in bacteria. Recent findings have shown that efflux impacts flagellum biosynthesis and motility in Escherichia coli and other bacteria. AcrR is known to be the major transcriptional repressor of AcrAB-TolC, the main multidrug efflux pump in E. coli and other Enterobacteriaceae. However, the underlying molecular mechanisms of how efflux and motility are co-regulated remain poorly understood. Here, we have studied the role of AcrR in direct regulation of motility in E. coli. By combining bioinformatics, electrophoretic mobility shift assays (EMSAs), gene expression, and motility experiments, we have found that AcrR represses motility in E. coli by directly repressing transcription of the flhDC operon, but not the other flagellum genes/operons tested. flhDC encodes the master regulator of flagellum biosynthesis and motility genes. We found that such regulation primarily occurs by direct binding of AcrR to the flhDC promoter region containing the first of the two predicted AcrR-binding sites identified in this promoter. This is the first report of direct regulation by AcrR of genes unrelated to efflux or detoxification. Moreover, we report that overexpression of AcrR restores to parental levels the increased swimming motility previously observed in E. coli strains without a functional AcrAB-TolC pump, and that such effect by AcrR is prevented by the AcrR ligand and AcrAB-TolC substrate ethidium bromide. Based on these and prior findings, we provide a novel model in which AcrR senses efflux and then co-regulates efflux and motility in E. coli to maintain homeostasis and escape hazards. IMPORTANCE Efflux and motility play a major role in bacterial growth, colonization, and survival. In Escherichia coli, the transcriptional repressor AcrR is known to directly repress efflux and was later found to also repress flagellum biosynthesis and motility by Kim et al. (J Microbiol Biotechnol 26:1824-1828, 2016, doi: 10.4014/jmb.1607.07058). However, it remained unknown whether AcrR represses flagellum biosynthesis and motility directly and through which target genes, or indirectly because of altering the amount of efflux. This study reveals that AcrR represses flagellum biosynthesis and motility by directly repressing the expression of the flhDC master regulator of flagellum biosynthesis and motility genes, but not the other flagellum genes tested. We also show that the antimicrobial, efflux pump substrate, and AcrR ligand ethidium bromide regulates motility via AcrR. Overall, these findings support a novel model of direct co-regulation of efflux and motility mediated by AcrR in response to stress in E. coli.
Collapse
Affiliation(s)
- Jessica Maldonado
- Department of Biology, California State University Northridge, Northridge, California, USA
| | - Barbara Czarnecka
- Department of Biology, California State University Northridge, Northridge, California, USA
| | - Dana E. Harmon
- Department of Biology, California State University Northridge, Northridge, California, USA
| | - Cristian Ruiz
- Department of Biology, California State University Northridge, Northridge, California, USA
| |
Collapse
|
10
|
Sanz-García F, Gil-Gil T, Laborda P, Blanco P, Ochoa-Sánchez LE, Baquero F, Martínez JL, Hernando-Amado S. Translating eco-evolutionary biology into therapy to tackle antibiotic resistance. Nat Rev Microbiol 2023; 21:671-685. [PMID: 37208461 DOI: 10.1038/s41579-023-00902-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/19/2023] [Indexed: 05/21/2023]
Abstract
Antibiotic resistance is currently one of the most important public health problems. The golden age of antibiotic discovery ended decades ago, and new approaches are urgently needed. Therefore, preserving the efficacy of the antibiotics currently in use and developing compounds and strategies that specifically target antibiotic-resistant pathogens is critical. The identification of robust trends of antibiotic resistance evolution and of its associated trade-offs, such as collateral sensitivity or fitness costs, is invaluable for the design of rational evolution-based, ecology-based treatment approaches. In this Review, we discuss these evolutionary trade-offs and how such knowledge can aid in informing combination or alternating antibiotic therapies against bacterial infections. In addition, we discuss how targeting bacterial metabolism can enhance drug activity and impair antibiotic resistance evolution. Finally, we explore how an improved understanding of the original physiological function of antibiotic resistance determinants, which have evolved to reach clinical resistance after a process of historical contingency, may help to tackle antibiotic resistance.
Collapse
Affiliation(s)
- Fernando Sanz-García
- Departamento de Microbiología, Medicina Preventiva y Salud Pública, Universidad de Zaragoza, Zaragoza, Spain
| | - Teresa Gil-Gil
- Centro Nacional de Biotecnología, CSIC, Darwin 3, Madrid, Spain
- Programa de Doctorado en Biociencias Moleculares, Universidad Autónoma de Madrid, Madrid, Spain
| | - Pablo Laborda
- Centro Nacional de Biotecnología, CSIC, Darwin 3, Madrid, Spain
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
- Department of Clinical Microbiology, 9301, Rigshospitalet, Copenhagen, Denmark
| | - Paula Blanco
- Molecular Basis of Adaptation, Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain
- VISAVET Health Surveillance Centre, Universidad Complutense Madrid, Madrid, Spain
| | | | - Fernando Baquero
- Department of Microbiology, Hospital Universitario Ramón y Cajal (IRYCIS), CIBER en Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | | | | |
Collapse
|
11
|
Wang Y, Wang X, Wu H, Wang L, Wang H, Lu Z. Characterization of Hsp17, a Novel Small Heat Shock Protein, in Sphingomonas melonis TY under Heat Stress. Microbiol Spectr 2023; 11:e0136023. [PMID: 37436164 PMCID: PMC10434288 DOI: 10.1128/spectrum.01360-23] [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: 03/29/2023] [Accepted: 06/24/2023] [Indexed: 07/13/2023] Open
Abstract
Bacteria are constantly exposed to a variety of environmental stresses. Temperature is considered one of the most important environmental factors affecting microbial growth and survival. As ubiquitous environmental microorganisms, Sphingomonas species play essential roles in the biodegradation of organic contaminants, plant protection, and environmental remediation. Understanding the mechanism by which they respond to heat shock will help further improve cell resistance by applying synthetic biological strategies. Here, we assessed the transcriptomic and proteomic responses of Sphingomonas melonis TY to heat shock and found that stressful conditions caused significant changes in functional genes related to protein synthesis at the transcriptional level. The most notable changes observed were increases in the transcription (1,857-fold) and protein expression (11-fold) of Hsp17, which belongs to the small heat shock protein family, and the function of Hsp17 in heat stress was further investigated in this study. We found that the deletion of hsp17 reduced the capacity of the cells to tolerate high temperatures, whereas the overexpression of hsp17 significantly enhanced the ability of the cells to withstand high temperatures. Moreover, the heterologous expression of hsp17 in Escherichia coli DH5α conferred to the bacterium the ability to resist heat stress. Interestingly, its cells were elongated and formed connected cells following the increase in temperature, while hsp17 overexpression restored their normal morphology under high temperature. In general, these results indicate that the novel small heat shock protein Hsp17 greatly contributes to maintaining cell viability and morphology under stress conditions. IMPORTANCE Temperature is generally considered the most important factor affecting metabolic functions and the survival of microbes. As molecular chaperones, small heat shock proteins can prevent damaged protein aggregation during abiotic stress, especially heat stress. Sphingomonas species are widely distributed in nature, and they can frequently be found in various extreme environments. However, the role of small heat shock proteins in Sphingomonas under high-temperature stress has not been elucidated. This study greatly enhances our understanding of a novel identified protein, Hsp17, in S. melonis TY in terms of its ability to resist heat stress and maintain cell morphology under high temperature, leading to a broader understanding of how microbes adapt to environmental extremes. Furthermore, our study will provide potential heat resistance elements for further enhancing cellular resistance as well as the synthetic biological applications of Sphingomonas.
Collapse
Affiliation(s)
- Yihan Wang
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
- Cancer Center, Zhejiang University, Hangzhou, China
| | - Xiaoyu Wang
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
- Cancer Center, Zhejiang University, Hangzhou, China
| | - Hao Wu
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
- Cancer Center, Zhejiang University, Hangzhou, China
| | - Lvjing Wang
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
- Cancer Center, Zhejiang University, Hangzhou, China
| | - Haixia Wang
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Zhenmei Lu
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
- Cancer Center, Zhejiang University, Hangzhou, China
| |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
Jang S. AcrAB-TolC, a major efflux pump in Gram negative bacteria: toward understanding its operation mechanism. BMB Rep 2023; 56:326-334. [PMID: 37254571 PMCID: PMC10315565 DOI: 10.5483/bmbrep.2023-0070] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 05/18/2023] [Accepted: 05/30/2023] [Indexed: 08/27/2023] Open
Abstract
Antibiotic resistance (AR) is a silent pandemic that kills millions worldwide. Although the development of new therapeutic agents against antibiotic resistance is in urgent demand, this has presented a great challenge, especially for Gram-negative bacteria that have inherent drug-resistance mediated by impermeable outer membranes and multidrug efflux pumps that actively extrude various drugs from the bacteria. For the last two decades, multidrug efflux pumps, including AcrAB-TolC, the most clinically important efflux pump in Gram-negative bacteria, have drawn great attention as strategic targets for re-sensitizing bacteria to the existing antibiotics. This article aims to provide a concise overview of the AcrAB-TolC operational mechanism, reviewing its architecture and substrate specificity, as well as the recent development of AcrAB-TolC inhibitors. [BMB Reports 2023; 56(6): 326-334].
Collapse
Affiliation(s)
- Soojin Jang
- Department of Discovery Biology, Antibacterial Resistance Laboratory, Institut Pasteur Korea, Seongnam 13488, Korea
| |
Collapse
|
14
|
Zhou K, Sun L, Zhang X, Xu X, Mi K, Ma W, Zhang L, Huang L. Salmonella antimicrobials inherited and the non-inherited resistance: mechanisms and alternative therapeutic strategies. Front Microbiol 2023; 14:1176317. [PMID: 37303797 PMCID: PMC10249997 DOI: 10.3389/fmicb.2023.1176317] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 04/24/2023] [Indexed: 06/13/2023] Open
Abstract
Salmonella spp. is one of the most important foodborne pathogens. Typhoid fever and enteritis caused by Salmonella enterica are associated with 16-33 million infections and 500,000 to 600,000 deaths annually worldwide. The eradication of Salmonella is becoming increasingly difficult because of its remarkable capacity to counter antimicrobial agents. In addition to the intrinsic and acquired resistance of Salmonella, increasing studies indicated that its non-inherited resistance, which commonly mentioned as biofilms and persister cells, plays a critical role in refractory infections and resistance evolution. These remind the urgent demand for new therapeutic strategies against Salmonella. This review starts with escape mechanisms of Salmonella against antimicrobial agents, with particular emphasis on the roles of the non-inherited resistance in antibiotic failure and resistance evolution. Then, drug design or therapeutic strategies that show impressive effects in overcoming Salmonella resistance and tolerance are summarized completely, such as overcoming the barrier of outer membrane by targeting MlaABC system, reducing persister cells by limiting hydrogen sulfide, and applying probiotics or predatory bacteria. Meanwhile, according to the clinical practice, the advantages and disadvantages of above strategies are discussed. Finally, we further analyze how to deal with this tricky problems, thus can promote above novel strategies to be applied in the clinic as soon as possible. We believed that this review will be helpful in understanding the relationships between tolerance phenotype and resistance of Salmonella as well as the efficient control of antibiotic resistance.
Collapse
Affiliation(s)
- Kaixiang Zhou
- Department of Veterinary Medicine Science, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- National Reference Laboratory of Veterinary Drug Residues (HZAU), Wuhan, Hubei, China
| | - Lei Sun
- Department of Veterinary Medicine Science, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- National Reference Laboratory of Veterinary Drug Residues (HZAU), Wuhan, Hubei, China
| | - Xuehua Zhang
- Department of Veterinary Medicine Science, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- National Reference Laboratory of Veterinary Drug Residues (HZAU), Wuhan, Hubei, China
| | - Xiangyue Xu
- Department of Veterinary Medicine Science, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- National Reference Laboratory of Veterinary Drug Residues (HZAU), Wuhan, Hubei, China
| | - Kun Mi
- Department of Veterinary Medicine Science, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- National Reference Laboratory of Veterinary Drug Residues (HZAU), Wuhan, Hubei, China
| | - Wenjin Ma
- Department of Veterinary Medicine Science, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- National Reference Laboratory of Veterinary Drug Residues (HZAU), Wuhan, Hubei, China
| | - Lan Zhang
- Department of Veterinary Medicine Science, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- National Reference Laboratory of Veterinary Drug Residues (HZAU), Wuhan, Hubei, China
| | - Lingli Huang
- Department of Veterinary Medicine Science, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- National Reference Laboratory of Veterinary Drug Residues (HZAU), Wuhan, Hubei, China
- MOA Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, Hubei, China
| |
Collapse
|
15
|
Coluccia M, Béranger A, Trirocco R, Fanelli G, Zanzi F, Colonna B, Grossi M, Prosseda G, Pasqua M. Role of the MDR Efflux Pump AcrAB in Epithelial Cell Invasion by Shigella flexneri. Biomolecules 2023; 13:biom13050823. [PMID: 37238693 DOI: 10.3390/biom13050823] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/03/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
The tripartite complex AcrAB-TolC is the major RND pump in Escherichia coli and other Enterobacteriaceae, including Shigella, the etiological agent of bacillary dysentery. In addition to conferring resistance to many classes of antibiotics, AcrAB plays a role in the pathogenesis and virulence of several bacterial pathogens. Here, we report data demonstrating that AcrAB specifically contributes to Shigella flexneri invasion of epithelial cells. We found that deletion of both acrA and acrB genes causes reduced survival of S. flexneri M90T strain within Caco-2 epithelial cells and prevents cell-to-cell spread of the bacteria. Infections with single deletion mutant strains indicate that both AcrA and AcrB favor the viability of the intracellular bacteria. Finally, we were able to further confirm the requirement of the AcrB transporter activity for intraepithelial survival by using a specific EP inhibitor. Overall, the data from the present study expand the role of the AcrAB pump to an important human pathogen, such as Shigella, and add insights into the mechanism governing the Shigella infection process.
Collapse
Affiliation(s)
- Marco Coluccia
- Istituto Pasteur Italy, Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, 00185 Rome, Italy
| | - Aude Béranger
- Istituto Pasteur Italy, Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, 00185 Rome, Italy
| | - Rita Trirocco
- Istituto Pasteur Italy, Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, 00185 Rome, Italy
| | - Giulia Fanelli
- Istituto Pasteur Italy, Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, 00185 Rome, Italy
| | - Francesco Zanzi
- Istituto Pasteur Italy, Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, 00185 Rome, Italy
| | - Bianca Colonna
- Istituto Pasteur Italy, Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, 00185 Rome, Italy
| | - Milena Grossi
- Istituto Pasteur Italy, Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, 00185 Rome, Italy
| | - Gianni Prosseda
- Istituto Pasteur Italy, Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, 00185 Rome, Italy
| | - Martina Pasqua
- Istituto Pasteur Italy, Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, 00185 Rome, Italy
| |
Collapse
|
16
|
Gaurav A, Bakht P, Saini M, Pandey S, Pathania R. Role of bacterial efflux pumps in antibiotic resistance, virulence, and strategies to discover novel efflux pump inhibitors. MICROBIOLOGY (READING, ENGLAND) 2023; 169. [PMID: 37224055 DOI: 10.1099/mic.0.001333] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The problem of antibiotic resistance among pathogenic bacteria has reached a crisis level. The treatment options against infections caused by multiple drug-resistant bacteria are shrinking gradually. The current pace of the discovery of new antibacterial entities is lagging behind the rate of development of new resistance. Efflux pumps play a central role in making a bacterium resistant to multiple antibiotics due to their ability to expel a wide range of structurally diverse compounds. Besides providing an escape from antibacterial compounds, efflux pumps are also involved in bacterial stress response, virulence, biofilm formation, and altering host physiology. Efflux pumps are unique yet challenging targets for the discovery of novel efflux pump inhibitors (EPIs). EPIs could help rejuvenate our currently dried pipeline of antibacterial drug discovery. The current article highlights the recent developments in the field of efflux pumps, challenges faced during the development of EPIs and potential approaches for their development. Additionally, this review highlights the utility of resources such as natural products and machine learning to expand our EPIs arsenal using these latest technologies.
Collapse
Affiliation(s)
- Amit Gaurav
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India
| | - Perwez Bakht
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India
| | - Mahak Saini
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India
| | - Shivam Pandey
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India
| | - Ranjana Pathania
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India
| |
Collapse
|
17
|
Wang M, Lian Y, Wang Y, Zhu L. The role and mechanism of quorum sensing on environmental antimicrobial resistance. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 322:121238. [PMID: 36758922 DOI: 10.1016/j.envpol.2023.121238] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 02/03/2023] [Accepted: 02/06/2023] [Indexed: 06/18/2023]
Abstract
As more environmental contaminants emerging, antibiotics and antibiotic resistance genes (ARGs) have caused a substantial increase of antimicrobial resistance (AMR) in environment. Quorum sensing (QS) is a bacterial cell-to-cell communication process that regulates many traits and gene expression, including ARGs and the related genes that contribute to AMR development. Herein, we summarize the role, physiology, and genetic mechanisms of bacterial QS in AMR development in the environment. First, the effect of QS on AMR is introduced. Next, the role of QS in bacterial physiological behaviors that promote AMR development, including membrane permeability, tactic movement, biofilm formation, persister formation, and small colony variants (SCVs), is systematically analyzed. Furthermore, the regulation of QS on the expression of ARGs, generation of reactive oxygen species (ROS), which affects ARGs formation, and horizontal gene transfer (HGT), which accelerates the transmission of ARGs, are discussed to reveal the molecular mechanism for AMR development. This review provides a reference for a better understanding of AMR evolution and novel insights into AMR prevention.
Collapse
Affiliation(s)
- Meizhen Wang
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China; Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou, 310012, China
| | - Yulu Lian
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China
| | - Yujie Wang
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China
| | - Lin Zhu
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China.
| |
Collapse
|
18
|
Pugh HL, Connor C, Siasat P, McNally A, Blair JMA. E. coli ST11 (O157:H7) does not encode a functional AcrF efflux pump. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001324. [PMID: 37074150 PMCID: PMC10202319 DOI: 10.1099/mic.0.001324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 03/23/2023] [Indexed: 04/20/2023]
Abstract
Escherichia coli is a facultative anaerobe found in a wide range of environments. Commonly described as the laboratory workhorse, E. coli is one of the best characterized bacterial species to date, however much of our understanding comes from studies involving the laboratory strain E. coli K-12. Resistance-nodulation-division efflux pumps are found in Gram-negative bacteria and can export a diverse range of substrates, including antibiotics. E. coli K-12 has six RND pumps; AcrB, AcrD, AcrF, CusA, MdtBC and MdtF, and it is frequently reported that all E. coli strains possess these six pumps. However, this is not true of E. coli ST11, a lineage of E. coli, which is primarily composed of the highly virulent important human pathogen, E. coli O157:H7. Here we show that acrF is absent from the pangenome of ST11 and that this lineage of E. coli has a highly conserved insertion within the acrF gene, which when translated encodes 13 amino acids and two stop codons. This insertion was found to be present in 97.59 % of 1787 ST11 genome assemblies. Non-function of AcrF in ST11 was confirmed in the laboratory as complementation with acrF from ST11 was unable to restore AcrF function in E. coli K-12 substr. MG1655 ΔacrB ΔacrF. This shows that the complement of RND efflux pumps present in laboratory bacterial strains may not reflect the situation in virulent strains of bacterial pathogens.
Collapse
Affiliation(s)
- Hannah L. Pugh
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Christopher Connor
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Pauline Siasat
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Alan McNally
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Jessica M. A. Blair
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| |
Collapse
|
19
|
Quan H, Gong X, Chen Q, Zheng F, Yu Y, Liu D, Wang W, Chu Y. Functional Characterization of a Novel SMR-Type Efflux Pump RanQ, Mediating Quaternary Ammonium Compound Resistance in Riemerella anatipestifer. Microorganisms 2023; 11:microorganisms11040907. [PMID: 37110330 PMCID: PMC10142375 DOI: 10.3390/microorganisms11040907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 03/28/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023] Open
Abstract
Riemerella anatipestifer (R. anatipestifer) is a multidrug-resistant bacterium and an important pathogen responsible for major economic losses in the duck industry. Our previous study revealed that the efflux pump is an important resistance mechanism of R. anatipestifer. Bioinformatics analysis indicated that the GE296_RS02355 gene (denoted here as RanQ), a putative small multidrug resistance (SMR)-type efflux pump, is highly conserved in R. anatipestifer strains and important for the multidrug resistance. In the present study, we characterized the GE296_RS02355 gene in R. anatipestifer strain LZ-01. First, the deletion strain RA-LZ01ΔGE296_RS02355 and complemented strain RA-LZ01cΔGE296_RS02355 were constructed. When compared with that of the wild-type (WT) strain RA-LZ01, the mutant strain ΔRanQ showed no significant influence on bacterial growth, virulence, invasion and adhesion, morphology biofilm formation ability, and glucose metabolism. In addition, the ΔRanQ mutant strain did not alter the drug resistance phenotype of the WT strain RA-LZ01 and displayed enhanced sensitivity toward structurally related quaternary ammonium compounds, such as benzalkonium chloride and methyl viologen, which show high efflux specificity and selectivity. This study may help elucidate the unprecedented biological functions of the SMR-type efflux pump in R. anatipestifer. Thus, if this determinant is horizontally transferred, it could cause the spread of quaternary ammonium compound resistance among bacterial species.
Collapse
Affiliation(s)
- Heng Quan
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou 730070, China
- State Key Laboratory of Veterinary Etiological Biology, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
| | - Xiaowei Gong
- State Key Laboratory of Veterinary Etiological Biology, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
| | - Qiwei Chen
- State Key Laboratory of Veterinary Etiological Biology, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
- Correspondence: (Q.C.); (W.W.)
| | - Fuying Zheng
- State Key Laboratory of Veterinary Etiological Biology, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
| | - Yongfeng Yu
- State Key Laboratory of Veterinary Etiological Biology, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
| | - Donghui Liu
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou 730070, China
- State Key Laboratory of Veterinary Etiological Biology, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
| | - Wenhui Wang
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou 730070, China
- Correspondence: (Q.C.); (W.W.)
| | - Yuefeng Chu
- State Key Laboratory of Veterinary Etiological Biology, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
| |
Collapse
|
20
|
Yi Y, Zhang J, Zuo J, Zhang M, Yang S, Huang Z, Li G, Shang R, Lin S. Novel pyridinium cationic pleuromutilin analogues overcoming bacterial multidrug resistance. Eur J Med Chem 2023; 251:115269. [PMID: 36924667 DOI: 10.1016/j.ejmech.2023.115269] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 03/07/2023] [Accepted: 03/08/2023] [Indexed: 03/13/2023]
Abstract
A series of pyridinium cation-substituted pleuromutilin analogues were designed, synthesized and evaluated for their antibacterial activities in vitro and in vivo. Most derivatives showed potent antibacterial activities, especially e4 that displayed the highest antibacterial activity against multi-drug resistant bacteria and was subjected to time-kill kinetics, resistance studies, cytotoxicity and molecular docking assays. Molecular docking results, scanning electron microscopy and o-nitrophenyl-β-galactopyranoside tests showed that e4 not only inhibited bacterial protein synthesis but also disrupted bacterial cell walls. Compound e4 showed an ED50 of 5.68 mg/kg against multi-drug resistant Staphylococcus aureus in infected mice model. In in vivo and in vitro toxicity tests, e4 showed low toxic effects with an LD50 of 879 mg/kg to mice. These results suggest that compound e4 may be considered as a new therapeutic candidate for bacterial infections.
Collapse
Affiliation(s)
- Yunpeng Yi
- Shandong Provincial Animal and Poultry Green Health Products Creation Engineering Laboratory, Institute of Poultry Science, Shandong Academy of Agricultural Science, Jinan, 250100, Shandong, China
| | - Jiaming Zhang
- Shandong Provincial Animal and Poultry Green Health Products Creation Engineering Laboratory, Institute of Poultry Science, Shandong Academy of Agricultural Science, Jinan, 250100, Shandong, China
| | - Jiakun Zuo
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 200241, Shanghai, China
| | - Maolu Zhang
- Shandong Provincial Animal and Poultry Green Health Products Creation Engineering Laboratory, Institute of Poultry Science, Shandong Academy of Agricultural Science, Jinan, 250100, Shandong, China
| | - Shifa Yang
- Shandong Provincial Animal and Poultry Green Health Products Creation Engineering Laboratory, Institute of Poultry Science, Shandong Academy of Agricultural Science, Jinan, 250100, Shandong, China
| | - Zhongli Huang
- Shandong Provincial Animal and Poultry Green Health Products Creation Engineering Laboratory, Institute of Poultry Science, Shandong Academy of Agricultural Science, Jinan, 250100, Shandong, China
| | - Guiyu Li
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, 730070, Gansu, China
| | - Ruofeng Shang
- Key Laboratory of New Animal Drug Project, Gansu Province/Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture and Rural Affairs/Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS, Lanzhou 730050, Gansu, China.
| | - Shuqian Lin
- Shandong Provincial Animal and Poultry Green Health Products Creation Engineering Laboratory, Institute of Poultry Science, Shandong Academy of Agricultural Science, Jinan, 250100, Shandong, China.
| |
Collapse
|
21
|
Guo T, Chen Y, Chen W, Semple SJ, Gu X, Polyak SW, Sun G, Venter H, Ma S. Design and synthesis of benzochromene derivatives as AcrB inhibitors for the reversal of bacterial multidrug resistance. Eur J Med Chem 2023; 249:115148. [PMID: 36709649 DOI: 10.1016/j.ejmech.2023.115148] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 01/17/2023] [Accepted: 01/22/2023] [Indexed: 01/26/2023]
Abstract
A series of novel benzo[h]chromene compounds were designed, synthesized and evaluated for their biological activity as AcrB inhibitors. The compounds were assessed for their ability to potentiate the effect of antibiotics. Compounds with antibiotic-potentiating effects were then evaluated for inhibition of Nile Red efflux, and for off-target effects including activity on the outer and inner bacterial membranes and toxicity. Six compounds were identified to reduce the MIC values of at least one of the tested antibiotics by at least 4-fold, and further reduced the MICs in the presence of a membrane permeabilizer. The identified compounds were also able to inhibit Nile Red efflux at concentrations between 50 μM and 200 μM. The compounds did not disrupt the bacterial outer membrane nor display toxicity in a nematode model (Caenorhabditis elegans). The 4-methoxyphenoxy)propoxy derivative compound G6 possessed the most potent antibacterial potentiation with erythromycin by 8-fold even without the presence of a membrane permeabilizer. Furthermore, H6, G6, G10 and G11 completely abolished the Nile Red efflux at a concentration of 50 μM. The 3,4-dihydro-2H-benzo[h]chromen-5-yl)(morpholino)methanone core appears to be a promising chemical skeleton to be further studied in the discovery of more putative AcrB inhibitors.
Collapse
Affiliation(s)
- Ting Guo
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, 250012, China
| | - Yang Chen
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5000, Australia
| | - Weijin Chen
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, 250012, China
| | - Susan J Semple
- Quality Use of Medicines and Pharmacy Research Centre, Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5000, Australia
| | - Xiaotong Gu
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, 250012, China
| | - Steven W Polyak
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5000, Australia
| | - Guanglin Sun
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, 250012, China
| | - Henrietta Venter
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5000, Australia.
| | - Shutao Ma
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, 250012, China.
| |
Collapse
|
22
|
Fanelli G, Pasqua M, Prosseda G, Grossi M, Colonna B. AcrAB efflux pump impacts on the survival of adherent-invasive Escherichia coli strain LF82 inside macrophages. Sci Rep 2023; 13:2692. [PMID: 36792672 PMCID: PMC9931695 DOI: 10.1038/s41598-023-29817-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 02/10/2023] [Indexed: 02/17/2023] Open
Abstract
The tripartite complex AcrAB-TolC is the major RND pump in Escherichia coli and other Enterobacteriaceae. It consists of the AcrB transporter, which is embedded in the inner membrane, the AcrA adapter located in the periplasm, and the channel protein TolC responsible for the transport of substrates towards the extracellular environment. Besides conferring resistance to many classes of antibiotics, AcrAB plays a role in the pathogenesis and virulence of several bacterial pathogens. Here we report that the AcrAB pump heavily affects the infection process of the LF82 strain, the prototype of Adherent-Invasive Escherichia coli (AIEC) which are highly abundant in the ileal mucosa of Chron disease patients. We found that the deletion of genes encoding AcrA and/or AcrB leads to decreased survival of LF82 within macrophages. Ectopic AcrAB expression in a acrAB defective mutant restores the wild type condition. Furthermore, we demonstrate that inhibition of AcrB and replacement of the transporter with an unfunctional AcrB also interfere with bacterial viability inside macrophages. Overall, these data suggest a pivotal role of the AcrAB efflux pump in bacteria-host cell interactions also in AIEC.
Collapse
Affiliation(s)
- Giulia Fanelli
- grid.7841.aDepartment of Biology and Biotechnology “C. Darwin”, Istituto Pasteur Italia, Sapienza Università di Roma, Rome, Italy
| | - Martina Pasqua
- grid.7841.aDepartment of Biology and Biotechnology “C. Darwin”, Istituto Pasteur Italia, Sapienza Università di Roma, Rome, Italy
| | - Gianni Prosseda
- grid.7841.aDepartment 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.
| |
Collapse
|
23
|
Tang Z, Zhang Y, Xiao S, Gao Y, Duan Y, Liu B, Xiong C, Yang Z, Wu Y, Zhou S. Insight into the impacts and mechanisms of ketone stress on the antibiotic resistance in Escherichia coli. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:83746-83755. [PMID: 35771331 PMCID: PMC9245865 DOI: 10.1007/s11356-022-21600-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 06/16/2022] [Indexed: 06/15/2023]
Abstract
Accumulation of toxic organic has posed a substantial pressure on the proliferation of bacterial resistance. While aromatic organics have been demonstrated to enhance the antibiotic resistance in bacteria, no information is yet available on the effects of non-aromatic organics on the variations of bacterial resistance. Here, we investigated the effects of a typical ketone (i.e., methylisobutanone (MIBK)) on the variations of antibiotic resistance in Escherichia coli (E. coli). The results showed that the growth of resistant E. coli under environmental concentration of 50 μg/L MIBK was firstly inhibited as explained by the transient disruption in the cell membrane and then recovered possibly due to the reactive oxygen species. Exposure to 50 μg/L MIBK gradually raised the abundance of representative resistance gene (ampR) in E. coli. In contrast, the high concentration of 50 mg/L MIBK continuously inhibited the growth of resistant E. coli by disrupting cell membrane and notably promoted the proliferation of ampR through enhancing the horizontal transformation and up-regulating the expression of efflux pump gene. These findings provided the first evidence for the evolution of bacterial resistance in response to ketone organics.
Collapse
Affiliation(s)
- Zhenping Tang
- Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, University of South China, Hengyang, 421001, China
- Hunan Province Key Laboratory of Rare Metal Minerals Exploitation and Geological Disposal of Wastes, University of South China, Hengyang, 421001, China
| | - Yu Zhang
- School of Civil Engineering, University of South China, Hengyang, 421001, China
| | - Shasha Xiao
- School of Civil Engineering, University of South China, Hengyang, 421001, China
| | - Yuanyuan Gao
- Hunan Province Key Laboratory of Rare Metal Minerals Exploitation and Geological Disposal of Wastes, University of South China, Hengyang, 421001, China
| | - Yi Duan
- Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, University of South China, Hengyang, 421001, China
- School of Civil Engineering, University of South China, Hengyang, 421001, China
| | - Boyang Liu
- School of Civil Engineering, University of South China, Hengyang, 421001, China
| | - Cong Xiong
- School of Civil Engineering, University of South China, Hengyang, 421001, China
| | - Zhengqing Yang
- School of Civil Engineering, University of South China, Hengyang, 421001, China
| | - Yueyue Wu
- Institute of Pathogenic Biology, Hengyang Medical School, University of South China, Hengyang, 421001, China
| | - Shuai Zhou
- Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, University of South China, Hengyang, 421001, China.
- Hunan Province Key Laboratory of Rare Metal Minerals Exploitation and Geological Disposal of Wastes, University of South China, Hengyang, 421001, China.
- School of Civil Engineering, University of South China, Hengyang, 421001, China.
| |
Collapse
|
24
|
A genetic platform to investigate the functions of bacterial drug efflux pumps. Nat Chem Biol 2022; 18:1399-1409. [PMID: 36065018 DOI: 10.1038/s41589-022-01119-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 07/21/2022] [Indexed: 11/08/2022]
Abstract
Efflux pumps are a serious challenge for the development of antibacterial agents. Overcoming efflux requires an in-depth understanding of efflux pump functions, specificities and the development of inhibitors. However, the complexities of efflux networks have limited such studies. To address these challenges, we generated Efflux KnockOut-35 (EKO-35), a highly susceptible Escherichia coli strain lacking 35 efflux pumps. We demonstrate the use of this strain by constructing an efflux platform comprising EKO-35 strains individually producing efflux pumps forming tripartite complexes with TolC. This platform was profiled against a curated diverse compound collection, which enabled us to define physicochemical properties that contribute to transport. We also show the E. coli drug efflux network is conditionally essential for growth, and that the platform can be used to investigate efflux pump inhibitor specificities and efflux pump interplay. We believe EKO-35 and the efflux platform will have widespread application for the study of drug efflux.
Collapse
|
25
|
Sionov RV, Steinberg D. Targeting the Holy Triangle of Quorum Sensing, Biofilm Formation, and Antibiotic Resistance in Pathogenic Bacteria. Microorganisms 2022; 10:1239. [PMID: 35744757 PMCID: PMC9228545 DOI: 10.3390/microorganisms10061239] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 06/12/2022] [Accepted: 06/14/2022] [Indexed: 12/12/2022] Open
Abstract
Chronic and recurrent bacterial infections are frequently associated with the formation of biofilms on biotic or abiotic materials that are composed of mono- or multi-species cultures of bacteria/fungi embedded in an extracellular matrix produced by the microorganisms. Biofilm formation is, among others, regulated by quorum sensing (QS) which is an interbacterial communication system usually composed of two-component systems (TCSs) of secreted autoinducer compounds that activate signal transduction pathways through interaction with their respective receptors. Embedded in the biofilms, the bacteria are protected from environmental stress stimuli, and they often show reduced responses to antibiotics, making it difficult to eradicate the bacterial infection. Besides reduced penetration of antibiotics through the intricate structure of the biofilms, the sessile biofilm-embedded bacteria show reduced metabolic activity making them intrinsically less sensitive to antibiotics. Moreover, they frequently express elevated levels of efflux pumps that extrude antibiotics, thereby reducing their intracellular levels. Some efflux pumps are involved in the secretion of QS compounds and biofilm-related materials, besides being important for removing toxic substances from the bacteria. Some efflux pump inhibitors (EPIs) have been shown to both prevent biofilm formation and sensitize the bacteria to antibiotics, suggesting a relationship between these processes. Additionally, QS inhibitors or quenchers may affect antibiotic susceptibility. Thus, targeting elements that regulate QS and biofilm formation might be a promising approach to combat antibiotic-resistant biofilm-related bacterial infections.
Collapse
Affiliation(s)
- Ronit Vogt Sionov
- The Biofilm Research Laboratory, The Institute of Biomedical and Oral Research, The Faculty of Dental Medicine, Hadassah Medical School, The Hebrew University, Jerusalem 9112102, Israel;
| | | |
Collapse
|
26
|
Distinct Potentially Adaptive Accumulation of Truncation Mutations in Salmonella enterica serovar Typhi and Salmonella enterica serovar Paratyphi A. Microbiol Spectr 2022; 10:e0196921. [PMID: 35467366 PMCID: PMC9241588 DOI: 10.1128/spectrum.01969-21] [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] [Indexed: 11/20/2022] Open
Abstract
Gene inactivation through the accumulation of truncation (or premature stop codon) mutations is a common mode of evolution in bacteria. It is frequently believed to result from reductive evolutionary processes allowing purging of superfluous traits. However, several works have demonstrated that, similar to the occurrences of inactivating nonsynonymous (i.e., amino acid replacement) mutations under positive selection pressures, truncation mutations can also be adaptive where specific traits deleterious in particular environmental conditions need to be inactivated for survival. Here, we performed a comparative analysis of genome-wide accumulation of truncation mutations in Salmonella enterica serovar Typhi and Salmonella enterica serovar Paratyphi A. Considering the known convergent evolutionary trajectories in these two serovars, we expected a strong overlap of truncated genes in S. Typhi and S. Paratyphi A, emerging through either reductive or adaptive dynamics. However, we detected a distinct set of core truncated genes encoding different overrepresented functional clusters in each serovar. In 54% and 28% truncated genes in S. Typhi and S. Paratyphi A, respectively, inactivating mutations were acquired by only different subsets of isolates, instead of all isolates analyzed for that serovar. Importantly, 62% truncated genes (P < 0.001) in S. Typhi and S. Paratyphi A were also targeted by convergent amino acid mutations in different serovars, suggesting those genes to be under selection pressures. Our findings indicate significant presence of potentially adaptive truncation mutations in conjunction with the ones emerging due to reductive evolution. Further experimental and large-scale bioinformatic studies are necessary to better explore the impact of such adaptive footprints of truncation mutations in the evolution of bacterial virulence. IMPORTANCE Detecting the adaptive mutations leading to gene inactivation or loss of function is crucial for understanding their contribution in the evolution of bacterial virulence and antibiotic resistance. Such inactivating mutations, apart from being of nonsynonymous (i.e., amino acid replacement) nature, can also be truncation mutations, abruptly trimming the length of encoded proteins. Importantly, the notion of reductive evolutionary dynamics is primarily accepted toward the accumulation of truncation mutations. However, our case study on S. Typhi and S. Paratyphi A, two human-restricted systemically invasive pathogens exerting similar clinical manifestations, indicated that a significant proportion of truncation mutations emerge from positive selection pressures. The candidate genes from our study will enable directed functional assays for deciphering the adaptive role of truncation mutations in S. Typhi and S. Paratyphi A pathogenesis. Also, our genome-level analytical approach will pave the way to understand the contribution of truncation mutations in the adaptive evolution of other bacterial pathogens.
Collapse
|
27
|
Akermi S, Smaoui S, Elhadef K, Fourati M, Louhichi N, Chaari M, Chakchouk Mtibaa A, Baanannou A, Masmoudi S, Mellouli L. Cupressus sempervirens Essential Oil: Exploring the Antibacterial Multitarget Mechanisms, Chemcomputational Toxicity Prediction, and Safety Assessment in Zebrafish Embryos. Molecules 2022; 27:2630. [PMID: 35565980 PMCID: PMC9103706 DOI: 10.3390/molecules27092630] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/11/2022] [Accepted: 04/18/2022] [Indexed: 12/11/2022] Open
Abstract
Nowadays, increasing interest has recently been given to the exploration of new food preservatives to avoid foodborne outbreaks or food spoilage. Likewise, new compounds that substitute the commonly used synthetic food preservatives are required to restrain the rising problem of microbial resistance. Accordingly, the present study was conducted to examine the chemical composition and the mechanism(s) of action of the Cupressus sempervirens essential oil (CSEO) against Salmonella enterica Typhimuriumand Staphyloccocus aureus. The gas chromatography analysis revealed α-pinene (38.47%) and δ-3-carene (25.14%) are the major components of the CSEO. By using computational methods, such as quantitative structure-activity relationship (QSAR), we revealed that many CSEO components had no toxic effects. Moreover, findings indicated that α-pinene, δ-3-carene and borneol, a minor compound of CSEO, could inhibit the AcrB-TolC and MepR efflux pump activity of S. enterica Typhimurium and S. aureus, respectively. In addition, our molecular docking predictions indicated the high affinity of these three compounds with active sites of bacterial DNA and RNA polymerases, pointing to plausible impairments of the pathogenic bacteria cell replication processes. As well, the safety profile was developed through the zebrafish model. The in vivo toxicological evaluation of (CSEO) exhibited a concentration-dependent manner, with a lethal concentration (LC50) equal to 6.6 µg/mL.
Collapse
Affiliation(s)
- Sarra Akermi
- Laboratory of Microbial Biotechnology and Engineering Enzymes (LMBEE), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (S.A.); (K.E.); (M.F.); (M.C.); (A.C.M.); (L.M.)
| | - Slim Smaoui
- Laboratory of Microbial Biotechnology and Engineering Enzymes (LMBEE), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (S.A.); (K.E.); (M.F.); (M.C.); (A.C.M.); (L.M.)
| | - Khaoula Elhadef
- Laboratory of Microbial Biotechnology and Engineering Enzymes (LMBEE), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (S.A.); (K.E.); (M.F.); (M.C.); (A.C.M.); (L.M.)
| | - Mariam Fourati
- Laboratory of Microbial Biotechnology and Engineering Enzymes (LMBEE), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (S.A.); (K.E.); (M.F.); (M.C.); (A.C.M.); (L.M.)
| | - Nacim Louhichi
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (N.L.); (A.B.); (S.M.)
| | - Moufida Chaari
- Laboratory of Microbial Biotechnology and Engineering Enzymes (LMBEE), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (S.A.); (K.E.); (M.F.); (M.C.); (A.C.M.); (L.M.)
| | - Ahlem Chakchouk Mtibaa
- Laboratory of Microbial Biotechnology and Engineering Enzymes (LMBEE), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (S.A.); (K.E.); (M.F.); (M.C.); (A.C.M.); (L.M.)
| | - Aissette Baanannou
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (N.L.); (A.B.); (S.M.)
| | - Saber Masmoudi
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (N.L.); (A.B.); (S.M.)
| | - Lotfi Mellouli
- Laboratory of Microbial Biotechnology and Engineering Enzymes (LMBEE), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (S.A.); (K.E.); (M.F.); (M.C.); (A.C.M.); (L.M.)
| |
Collapse
|
28
|
Youlden G, McNeil HE, Blair JMA, Jabbari S, King JR. Mathematical Modelling Highlights the Potential for Genetic Manipulation as an Adjuvant to Counter Efflux-Mediated MDR in Salmonella. Bull Math Biol 2022; 84:56. [PMID: 35380320 PMCID: PMC8983579 DOI: 10.1007/s11538-022-01011-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 03/02/2022] [Indexed: 11/18/2022]
Abstract
Bacteria have developed resistance to antibiotics by various mechanisms, notable amongst these is the use of permeation barriers and the expulsion of antibiotics via efflux pumps. The resistance-nodulation-division (RND) family of efflux pumps is found in Gram-negative bacteria and a major contributor to multidrug resistance (MDR). In particular, Salmonella encodes five RND efflux pump systems: AcrAB, AcrAD, AcrEF, MdsAB and MdtAB which have different substrate ranges including many antibiotics. We produce a spatial partial differential equation (PDE) model governing the diffusion and efflux of antibiotic in Salmonella, via these RND efflux pumps. Using parameter fitting techniques on experimental data, we are able to establish the behaviour of multiple wild-type and efflux mutant Salmonella strains, which enables us to produce efflux profiles for each individual efflux pump system. By combining the model with a gene regulatory network (GRN) model of efflux regulation, we simulate how the bacteria respond to their environment. Finally, performing a parameter sensitivity analysis, we look into various different targets to inhibit the efflux pumps. The model provides an in silico framework with which to test these potential adjuvants to counter MDR.
Collapse
Affiliation(s)
- George Youlden
- School of Mathematics, University of Birmingham, Birmingham, B15 2TT, UK.
- School of Mathematical Sciences, University of Nottingham, Nottingham, NG7 2RD, UK.
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK.
| | - Helen E McNeil
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK
| | - Jessica M A Blair
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK
| | - Sara Jabbari
- School of Mathematics, University of Birmingham, Birmingham, B15 2TT, UK
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK
| | - John R King
- School of Mathematical Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| |
Collapse
|
29
|
A role for the periplasmic adaptor protein AcrA in vetting substrate access to the RND efflux transporter AcrB. Sci Rep 2022; 12:4752. [PMID: 35306531 PMCID: PMC8934357 DOI: 10.1038/s41598-022-08903-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 03/14/2022] [Indexed: 11/08/2022] Open
Abstract
Tripartite resistance-nodulation-division (RND) efflux pumps, such as AcrAB-TolC of Salmonella Typhimurium, contribute to antibiotic resistance and comprise an inner membrane RND-transporter, an outer membrane factor, and a periplasmic adaptor protein (PAP). The role of the PAP in the assembly and active transport process remains poorly understood. Here, we identify the functionally critical residues involved in PAP-RND-transporter binding between AcrA and AcrB and show that the corresponding RND-binding residues in the closely related PAP AcrE, are also important for its interaction with AcrB. We also report a residue in the membrane-proximal domain of AcrA, that when mutated, differentially affects the transport of substrates utilising different AcrB efflux channels, namely channels 1 and 2. This supports a potential role for the PAP in sensing the substrate-occupied state of the proximal binding pocket of the transporter and substrate vetting. Understanding the PAP’s role in the assembly and function of tripartite RND pumps can guide novel ways to inhibit their function to combat antibiotic resistance.
Collapse
|
30
|
Potential Synergistic Antibiotic Combinations against Fluoroquinolone-Resistant Pseudomonas aeruginosa. Pharmaceuticals (Basel) 2022; 15:ph15020243. [PMID: 35215357 PMCID: PMC8880063 DOI: 10.3390/ph15020243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 02/10/2022] [Accepted: 02/14/2022] [Indexed: 02/04/2023] Open
Abstract
The rise in multiple-drug-resistant (MDR) phenotypes in Gram-negative pathogens is a major public health crisis. Pseudomonas aeruginosa is one of the leading causes of nosocomial infections in clinics. Treatment options for P. aeruginosa have become increasingly difficult due tdo its remarkable capacity to resist multiple antibiotics. The presence of intrinsic resistance factors and the ability to quickly adapt to antibiotic monotherapy warrant us to look for alternative strategies like combinatorial antibiotic therapy. Here, we report the frequency of P. aeruginosa multidrug-resistant and extensively drug-resistance (XDR) phenotypes in a super-specialty tertiary care hospital in north India. Approximately 60 percent of all isolated P. aeruginosa strains displayed the MDR phenotype. We found highest antibiotic resistance frequency in the emergency department (EMR), as 20 percent of isolates were resistant to 15 antipseudomonal antibiotics. Presence of plasmids with quinolone-resistance determinants were major drivers for resistance against fluoroquinolone. Additionally, we explored the possible combinatorial therapeutic options with four antipseudomonal antibiotics—colistin, ciprofloxacin, tobramycin, and meropenem. We uncovered an association between different antibiotic interactions. Our data show that the combination of colistin and ciprofloxacin could be an effective combinatorial regimen to treat infections caused by MDR and XDR P. aeruginosa.
Collapse
|
31
|
Morsky B, Vural DC. Suppressing evolution of antibiotic resistance through environmental switching. THEOR ECOL-NETH 2022. [DOI: 10.1007/s12080-022-00530-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
32
|
Mehta J, Rolta R, Dev K. Role of medicinal plants from North Western Himalayas as an efflux pump inhibitor against MDR AcrAB-TolC Salmonella enterica serovar typhimurium: In vitro and In silico studies. JOURNAL OF ETHNOPHARMACOLOGY 2022; 282:114589. [PMID: 34492321 DOI: 10.1016/j.jep.2021.114589] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 08/20/2021] [Accepted: 08/29/2021] [Indexed: 06/13/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Zingiber officinale Roscoe has been utilized traditionally to cure various diseases like cold, cough, diarrhoea, nausea, asthma, vomiting, toothache, stomach upset, respiratory disorders, joint pain, and throat infection. It is also consumed as spices and ginger tea. AIM OF THE STUDY The current study was aimed to identify the phytocompounds of traditional medicinal plants of North-Western Himalaya that could inhibit the AcrAB-TolC efflux pump activity of Salmonella typhimurium and become sensitive to antibiotic killing at reduced dosage. MATERIAL AND METHODS Medicinal plant extracts were prepared using methanol, aqueous, and ethyl acetate and tested for efflux pump inhibitory activity of Salmonella typhimurium NKS70, NKS174, and NKS773 strains using Ethidium Bromide (EtBr)-agar cartwheel assay. Synergism was assessed by the agar well diffusion method and EPI activity by berberine uptake and EtBr efflux inhibition assays. Microdilution method and checkerboard assays were done to determine the minimum inhibitory concentration (MIC) and fractional inhibitory concentration index (FICI) respectively for a bioactive compound. To validate the phytocompound and efflux pump interaction, molecular docking with 6IE8 (RamA) and 6IE9 (RamR) targets was done using autoDock vina software. Toxicity prediction and drug-likeness were predicted by using ProTox-II and Molinspiration respectively. RESULTS Methanolic and ethyl acetate extracts of P. integerrima, O. sanctum, C. asiatica, M. charantia, Z. officinale, and W. somnifera in combination with ciprofloxacin and tetracycline showed synergistic antimicrobial activity with GIIs of 0.61-1.32 and GIIs 0.56-1.35 respectively. Methanolic extract of Z. officinal enhanced the antimicrobial potency of berberine (2 to 4-folds) and increased the EtBr accumulation. Furthermore, bioassay-guided fractionation leads to the identification of lariciresinol in ethyl acetate fraction, which decreased the MIC by 2-to 4-folds. The ΣFIC values varied from 0.30 to 0.55 with tetracycline, that indicated synergistic/additive effects. Lariciresinol also showed a good binding affinity with 6IE8 (-7.4 kcal mol-1) and 6IE9 (-8.2 kcal mol-1), which is comparable to tetracycline and chenodeoxycholic acid. Lariciresinol followed Lipinski's rule of five. CONCLUSION The data suggest that lariciresinol from Z. officinale could be a potential efflux pump inhibitor that could lead to effective killing of drug resistant Salmonella typhimurium at lower MIC. Molecular docking confirmed the antibacterial EPI mechanism of lariciresinol in Salmonella typhimurium and confirmed to be safe for future use.
Collapse
Affiliation(s)
- Jyoti Mehta
- Faculty of Applied Sciences and Biotechnology, Shoolini University of Biotechnology and Management Sciences, Bajhol, PO Sultanpur, District Solan, 173229, Himachal Pradesh, India.
| | - Rajan Rolta
- Faculty of Applied Sciences and Biotechnology, Shoolini University of Biotechnology and Management Sciences, Bajhol, PO Sultanpur, District Solan, 173229, Himachal Pradesh, India
| | - Kamal Dev
- Faculty of Applied Sciences and Biotechnology, Shoolini University of Biotechnology and Management Sciences, Bajhol, PO Sultanpur, District Solan, 173229, Himachal Pradesh, India.
| |
Collapse
|
33
|
Nishino K, Yamasaki S, Nakashima R, Zwama M, Hayashi-Nishino M. Function and Inhibitory Mechanisms of Multidrug Efflux Pumps. Front Microbiol 2021; 12:737288. [PMID: 34925258 PMCID: PMC8678522 DOI: 10.3389/fmicb.2021.737288] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 10/14/2021] [Indexed: 12/31/2022] Open
Abstract
Multidrug efflux pumps are inner membrane transporters that export multiple antibiotics from the inside to the outside of bacterial cells, contributing to bacterial multidrug resistance (MDR). Postgenomic analysis has demonstrated that numerous multidrug efflux pumps exist in bacteria. Also, the co-crystal structural analysis of multidrug efflux pumps revealed the drug recognition and export mechanisms, and the inhibitory mechanisms of the pumps. A single multidrug efflux pump can export multiple antibiotics; hence, developing efflux pump inhibitors is crucial in overcoming infectious diseases caused by multidrug-resistant bacteria. This review article describes the role of multidrug efflux pumps in MDR, and their physiological functions and inhibitory mechanisms.
Collapse
Affiliation(s)
- Kunihiko Nishino
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Osaka, Japan
| | - Seiji Yamasaki
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Osaka, Japan
| | - Ryosuke Nakashima
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Osaka, Japan
| | - Martijn Zwama
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Osaka, Japan
| | - Mitsuko Hayashi-Nishino
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Osaka, Japan
| |
Collapse
|
34
|
Ciusa ML, Marshall RL, Ricci V, Stone JW, Piddock LJV. Absence, loss-of-function, or inhibition of Escherichia coli AcrB does not increase expression of other efflux pump genes supporting the discovery of AcrB inhibitors as antibiotic adjuvants. J Antimicrob Chemother 2021; 77:633-640. [PMID: 34897478 PMCID: PMC8865010 DOI: 10.1093/jac/dkab452] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 11/11/2021] [Indexed: 11/16/2022] Open
Abstract
Objectives To determine whether expression of efflux pumps and antibiotic susceptibility are altered in Escherichia coli in response to efflux inhibition. Methods The promoter regions of nine efflux pump genes (acrAB, acrD, acrEF, emrAB, macAB, cusCFBA, mdtK, mdtABC, mdfA) were fused to gfp in pMW82 and fluorescence from each reporter construct was used as a measure of the transcriptional response to conditions in which AcrB was inhibited, absent or made non-functional. Expression was also determined by RT-qPCR. Drug susceptibility of efflux pump mutants with missense mutations known or predicted to cause loss of function of the encoded efflux pump was investigated. Results Data from the GFP reporter constructs revealed that no increased expression of the tested efflux pump genes was observed when AcrB was absent, made non-functional, or inhibited by an efflux pump inhibitor/competitive substrate, such as PAβN or chlorpromazine. This was confirmed by RT-qPCR for PAβN and chlorpromazine; however, a small but significant increase in macB gene expression was seen when acrB is deleted. Efflux inhibitors only synergized with antibiotics in the presence of a functional AcrB. When AcrB was absent or non-functional, there was no impact on MICs when other efflux pumps were also made non-functional. Conclusions Absence, loss-of-function, or inhibition of E. coli AcrB did not significantly increase expression of other efflux pump genes, which suggests there is no compensatory mechanism to overcome efflux inhibition and supports the discovery of inhibitors of AcrB as antibiotic adjuvants.
Collapse
Affiliation(s)
- Maria Laura Ciusa
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Robert L Marshall
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Vito Ricci
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Jack W Stone
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Laura J V Piddock
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| |
Collapse
|
35
|
Cuesta Bernal J, El-Delik J, Göttig S, Pos KM. Characterization and Molecular Determinants for β-Lactam Specificity of the Multidrug Efflux Pump AcrD from Salmonella typhimurium. Antibiotics (Basel) 2021; 10:antibiotics10121494. [PMID: 34943706 PMCID: PMC8699017 DOI: 10.3390/antibiotics10121494] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/26/2021] [Accepted: 12/01/2021] [Indexed: 11/24/2022] Open
Abstract
Gram-negative Tripartite Resistance Nodulation and cell Division (RND) superfamily efflux pumps confer various functions, including multidrug and bile salt resistance, quorum-sensing, virulence and can influence the rate of mutations on the chromosome. Multidrug RND efflux systems are often characterized by a wide substrate specificity. Similarly to many other RND efflux pump systems, AcrAD-TolC confers resistance toward SDS, novobiocin and deoxycholate. In contrast to the other pumps, however, it in addition confers resistance against aminoglycosides and dianionic β-lactams, such as sulbenicillin, aztreonam and carbenicillin. Here, we could show that AcrD from Salmonella typhimurium confers resistance toward several hitherto unreported AcrD substrates such as temocillin, dicloxacillin, cefazolin and fusidic acid. In order to address the molecular determinants of the S. typhimurium AcrD substrate specificity, we conducted substitution analyses in the putative access and deep binding pockets and in the TM1/TM2 groove region. The variants were tested in E. coli ΔacrBΔacrD against β-lactams oxacillin, carbenicillin, aztreonam and temocillin. Deep binding pocket variants N136A, D276A and Y327A; access pocket variant R625A; and variants with substitutions in the groove region between TM1 and TM2 conferred a sensitive phenotype and might, therefore, be involved in anionic β-lactam export. In contrast, lower susceptibilities were observed for E. coli cells harbouring deep binding pocket variants T139A, D176A, S180A, F609A, T611A and F627A and the TM1/TM2 groove variant I337A. This study provides the first insights of side chains involved in drug binding and transport for AcrD from S. typhimurium.
Collapse
Affiliation(s)
- Jenifer Cuesta Bernal
- Institute of Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany; (J.C.B.); (J.E.-D.)
| | - Jasmin El-Delik
- Institute of Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany; (J.C.B.); (J.E.-D.)
| | - Stephan Göttig
- Institute of Medical Microbiology and Infection Control, Hospital of the Goethe University, Paul-Ehrlich-Straße 40, D-60596 Frankfurt am Main, Germany;
| | - Klaas M. Pos
- Institute of Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany; (J.C.B.); (J.E.-D.)
- Correspondence:
| |
Collapse
|
36
|
Abstract
For antibiotics with intracellular targets, effective treatment of bacterial infections requires the drug to accumulate to a high concentration inside cells. Bacteria produce a complex cell envelope and possess drug export efflux pumps to limit drug accumulation inside cells. Decreasing cell envelope permeability and increasing efflux pump activity can reduce intracellular accumulation of antibiotics and are commonly seen in antibiotic-resistant strains. Here, we show that the balance between influx and efflux differs depending on bacterial growth phase in Gram-negative bacteria. Accumulation of the fluorescent compound ethidium bromide (EtBr) was measured in Salmonella enterica serovar Typhimurium SL1344 (wild type) and efflux deficient (ΔacrB) strains during growth. In SL1344, EtBr accumulation remained low, regardless of growth phase, and did not correlate with acrAB transcription. EtBr accumulation in the ΔacrB strains was high in exponential phase but dropped sharply later in growth, with no significant difference from that in SL1344 in stationary phase. Low EtBr accumulation in stationary phase was not due to the upregulation of other efflux pumps but instead was due to decreased permeability of the envelope in stationary phase. Transcriptome sequencing (RNA-seq) identified changes in expression of several pathways that remodel the envelope in stationary phase, leading to lower permeability.
Collapse
|
37
|
Hadchity L, Lanois A, Kiwan P, Nassar F, Givaudan A, Khattar ZA. AcrAB, the major RND-type efflux pump of Photorhabdus laumondii, confers intrinsic multidrug-resistance and contributes to virulence in insects. ENVIRONMENTAL MICROBIOLOGY REPORTS 2021; 13:637-648. [PMID: 34002534 DOI: 10.1111/1758-2229.12974] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 05/04/2021] [Indexed: 06/12/2023]
Abstract
The resistance-nodulation-division (RND)-type efflux pumps AcrAB and MdtABC contribute to multidrug-resistance (MDR) in Gram-negative bacteria. Photorhabdus is a symbiotic bacterium of soil nematodes that also produces virulence factors killing insects by septicaemia. We previously showed that mdtA deletion in Photorhabdus laumondii TT01 resulted in no detrimental phenotypes. Here, we investigated the roles of the last two putative RND transporters in TT01 genome, AcrAB and AcrAB-like (Plu0759-Plu0758). Only ΔacrA and ΔmdtAΔacrA mutants were multidrug sensitive, even to triphenyltetrazolium chloride and bromothymol blue used for Photorhabdus isolation from nematodes on the nutrient bromothymol blue-triphenyltetrazolium chloride agar (NBTA) medium. Both mutants also displayed slightly attenuated virulence after injection into Spodoptera littoralis. Transcriptional analysis revealed intermediate levels of acrAB expression in vitro, in vivo and post-mortem, whereas its putative transcriptional repressor acrR was weakly expressed. Yet, plasmid-mediated acrR overexpression did not decrease acrAB transcript levels neither MDR in TT01 WT. While no pertinent mutations were detected in acrR of the same P. laumondii strain grown either on NBTA or nutrient agar, we suggest that AcrR-mediated repression of acrAB is not physiologically required under conditions tested. Finally, we propose that AcrAB is the primary RND-efflux pump, which is essential for MDR in Photorhabdus and may confer adaptive advantages during insect infection.
Collapse
Affiliation(s)
- Linda Hadchity
- Laboratory of Georesources, Geosciences and Environment (L2GE), Microbiology/Tox-Ecotoxicology team, Faculty of Sciences 2, Lebanese University, Fanar, Lebanon
- DGIMI, Université Montpellier, INRAE, Montpellier, France
| | - Anne Lanois
- DGIMI, Université Montpellier, INRAE, Montpellier, France
| | - Paloma Kiwan
- Laboratory of Georesources, Geosciences and Environment (L2GE), Microbiology/Tox-Ecotoxicology team, Faculty of Sciences 2, Lebanese University, Fanar, Lebanon
| | - Fida Nassar
- Laboratory of Georesources, Geosciences and Environment (L2GE), Microbiology/Tox-Ecotoxicology team, Faculty of Sciences 2, Lebanese University, Fanar, Lebanon
| | - Alain Givaudan
- DGIMI, Université Montpellier, INRAE, Montpellier, France
| | - Ziad Abi Khattar
- Laboratory of Georesources, Geosciences and Environment (L2GE), Microbiology/Tox-Ecotoxicology team, Faculty of Sciences 2, Lebanese University, Fanar, Lebanon
| |
Collapse
|
38
|
Mateus C, Nunes AR, Oleastro M, Domingues F, Ferreira S. RND Efflux Systems Contribute to Resistance and Virulence of Aliarcobacter butzleri. Antibiotics (Basel) 2021; 10:823. [PMID: 34356744 PMCID: PMC8300790 DOI: 10.3390/antibiotics10070823] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/01/2021] [Accepted: 07/05/2021] [Indexed: 12/22/2022] Open
Abstract
Aliarcobacter butzleri is an emergent enteropathogen that can be found in a range of environments. This bacterium presents a vast repertoire of efflux pumps, such as the ones belonging to the resistance nodulation cell division family, which may be associated with bacterial resistance, as well as virulence. Thus, this work aimed to evaluate the contribution of three RND efflux systems, AreABC, AreDEF and AreGHI, in the resistance and virulence of A. butzleri. Mutant strains were constructed by inactivation of the gene that encodes the inner membrane protein of these systems. The bacterial resistance profile of parental and mutant strains to several antimicrobials was assessed, as was the intracellular accumulation of the ethidium bromide dye. Regarding bacterial virulence, the role of these three efflux pumps on growth, strain fitness, motility, biofilm formation ability, survival in adverse conditions (oxidative stress and bile salts) and human serum and in vitro adhesion and invasion to Caco-2 cells was evaluated. We observed that the mutants from the three efflux pumps were more susceptible to several classes of antimicrobials than the parental strain and presented an increase in the accumulation of ethidium bromide, indicating a potential role of the efflux pumps in the extrusion of antimicrobials. The mutant strains had no bacterial growth defects; nonetheless, they presented a reduction in relative fitness. For the three mutants, an increase in the susceptibility to oxidative stress was observed, while only the mutant for AreGHI efflux pump showed a relevant role in bile stress survival. All the mutant strains showed an impairment in biofilm formation ability, were more susceptible to human serum and were less adherent to intestinal epithelial cells. Overall, the results support the contribution of the efflux pumps AreABC, AreDEF and AreGHI of A. butzleri to antimicrobial resistance, as well as to bacterial virulence.
Collapse
Affiliation(s)
- Cristiana Mateus
- CICS-UBI-Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal; (C.M.); (A.R.N.); (F.D.)
| | - Ana Rita Nunes
- CICS-UBI-Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal; (C.M.); (A.R.N.); (F.D.)
| | - Mónica Oleastro
- National Reference Laboratory for Gastrointestinal Infections, Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016 Lisbon, Portugal;
| | - Fernanda Domingues
- CICS-UBI-Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal; (C.M.); (A.R.N.); (F.D.)
| | - Susana Ferreira
- CICS-UBI-Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal; (C.M.); (A.R.N.); (F.D.)
| |
Collapse
|
39
|
Analysis of the Oxidative Stress Regulon Identifies soxS as a Genetic Target for Resistance Reversal in Multidrug-Resistant Klebsiella pneumoniae. mBio 2021; 12:e0086721. [PMID: 34098732 PMCID: PMC8262902 DOI: 10.1128/mbio.00867-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
In bacteria, the defense system deployed to counter oxidative stress is orchestrated by three transcriptional factors, SoxS, SoxR, and OxyR. Although the regulon that these factors control is known in many bacteria, similar data are not available for Klebsiella pneumoniae. To address this data gap, oxidative stress was artificially induced in K. pneumoniae MGH78578 using paraquat and the corresponding oxidative stress regulon recorded using transcriptome sequencing (RNA-seq). The soxS gene was significantly induced during oxidative stress, and a knockout mutant was constructed to explore its functionality. The wild type and mutant were grown in the presence of paraquat and subjected to RNA-seq to elucidate the soxS regulon in K. pneumoniae MGH78578. Genes that are commonly regulated both in the oxidative stress and soxS regulons were identified and denoted as the oxidative SoxS regulon; these included a group of genes specifically regulated by SoxS. Efflux pump-encoding genes and global regulators were identified as part of this regulon. Consequently, the isogenic soxS mutant was found to exhibit a reduction in the minimum bactericidal concentration against tetracycline compared to that of the wild type. Impaired efflux activity, allowing tetracycline to be accumulated in the cytoplasm to bactericidal levels, was further evaluated using a tetraphenylphosphonium (TPP+) accumulation assay. The soxS mutant was also susceptible to tetracycline in vivo in a zebrafish embryo model. We conclude that the soxS gene could be considered a genetic target against which an inhibitor could be developed and used in combinatorial therapy to combat infections associated with multidrug-resistant K. pneumoniae.
Collapse
|
40
|
Rybenkov VV, Zgurskaya HI, Ganguly C, Leus IV, Zhang Z, Moniruzzaman M. The Whole Is Bigger than the Sum of Its Parts: Drug Transport in the Context of Two Membranes with Active Efflux. Chem Rev 2021; 121:5597-5631. [PMID: 33596653 PMCID: PMC8369882 DOI: 10.1021/acs.chemrev.0c01137] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cell envelope plays a dual role in the life of bacteria by simultaneously protecting it from a hostile environment and facilitating access to beneficial molecules. At the heart of this ability lie the restrictive properties of the cellular membrane augmented by efflux transporters, which preclude intracellular penetration of most molecules except with the help of specialized uptake mediators. Recently, kinetic properties of the cell envelope came into focus driven on one hand by the urgent need in new antibiotics and, on the other hand, by experimental and theoretical advances in studies of transmembrane transport. A notable result from these studies is the development of a kinetic formalism that integrates the Michaelis-Menten behavior of individual transporters with transmembrane diffusion and offers a quantitative basis for the analysis of intracellular penetration of bioactive compounds. This review surveys key experimental and computational approaches to the investigation of transport by individual translocators and in whole cells, summarizes key findings from these studies and outlines implications for antibiotic discovery. Special emphasis is placed on Gram-negative bacteria, whose envelope contains two separate membranes. This feature sets these organisms apart from Gram-positive bacteria and eukaryotic cells by providing them with full benefits of the synergy between slow transmembrane diffusion and active efflux.
Collapse
Affiliation(s)
- Valentin V Rybenkov
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Helen I Zgurskaya
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Chhandosee Ganguly
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Inga V Leus
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Zhen Zhang
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Mohammad Moniruzzaman
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| |
Collapse
|
41
|
Alav I, Kobylka J, Kuth MS, Pos KM, Picard M, Blair JMA, Bavro VN. Structure, Assembly, and Function of Tripartite Efflux and Type 1 Secretion Systems in Gram-Negative Bacteria. Chem Rev 2021; 121:5479-5596. [PMID: 33909410 PMCID: PMC8277102 DOI: 10.1021/acs.chemrev.1c00055] [Citation(s) in RCA: 99] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Indexed: 12/11/2022]
Abstract
Tripartite efflux pumps and the related type 1 secretion systems (T1SSs) in Gram-negative organisms are diverse in function, energization, and structural organization. They form continuous conduits spanning both the inner and the outer membrane and are composed of three principal components-the energized inner membrane transporters (belonging to ABC, RND, and MFS families), the outer membrane factor channel-like proteins, and linking the two, the periplasmic adaptor proteins (PAPs), also known as the membrane fusion proteins (MFPs). In this review we summarize the recent advances in understanding of structural biology, function, and regulation of these systems, highlighting the previously undescribed role of PAPs in providing a common architectural scaffold across diverse families of transporters. Despite being built from a limited number of basic structural domains, these complexes present a staggering variety of architectures. While key insights have been derived from the RND transporter systems, a closer inspection of the operation and structural organization of different tripartite systems reveals unexpected analogies between them, including those formed around MFS- and ATP-driven transporters, suggesting that they operate around basic common principles. Based on that we are proposing a new integrated model of PAP-mediated communication within the conformational cycling of tripartite systems, which could be expanded to other types of assemblies.
Collapse
Affiliation(s)
- Ilyas Alav
- Institute
of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Jessica Kobylka
- Institute
of Biochemistry, Biocenter, Goethe Universität
Frankfurt, Max-von-Laue-Straße 9, D-60438 Frankfurt, Germany
| | - Miriam S. Kuth
- Institute
of Biochemistry, Biocenter, Goethe Universität
Frankfurt, Max-von-Laue-Straße 9, D-60438 Frankfurt, Germany
| | - Klaas M. Pos
- Institute
of Biochemistry, Biocenter, Goethe Universität
Frankfurt, Max-von-Laue-Straße 9, D-60438 Frankfurt, Germany
| | - Martin Picard
- Laboratoire
de Biologie Physico-Chimique des Protéines Membranaires, CNRS
UMR 7099, Université de Paris, 75005 Paris, France
- Fondation
Edmond de Rothschild pour le développement de la recherche
Scientifique, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Jessica M. A. Blair
- Institute
of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Vassiliy N. Bavro
- School
of Life Sciences, University of Essex, Colchester, CO4 3SQ United Kingdom
| |
Collapse
|
42
|
The multi-drug efflux system AcrABZ-TolC is essential for infection of Salmonella Typhimurium by the flagellum-dependent bacteriophage Chi. J Virol 2021; 95:JVI.00394-21. [PMID: 33731456 PMCID: PMC8139690 DOI: 10.1128/jvi.00394-21] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bacteriophages are the most abundant biological entities in the biosphere. Due to their host specificity and ability to kill bacteria rapidly, bacteriophages have many potential healthcare applications, including therapy against antibiotic-resistant bacteria. Infection by flagellotropic bacteriophages requires a properly rotating bacterial flagellar filament. The flagella-dependent phage χ (Chi) infects serovars of the pathogenic enterobacterium Salmonella enterica However, cell surface receptors and proteins involved in other stages of χ infection have not been discovered to date. We screened a multi-gene deletion library of S. enterica serovar Typhimurium by spotting mutants on soft agar plates seeded with bacteriophage χ and monitoring their ability to grow and form a swim ring, a characteristic of bacteriophage-resistant motile mutants. Those multi-gene deletion regions identified to be important for χ infectivity were further investigated by characterizing the phenotypes of corresponding single-gene deletion mutants. This way, we identified motile mutants with varying degrees of resistance to χ. Deletions in individual genes encoding the AcrABZ-TolC multi-drug efflux system drastically reduced infection by bacteriophage χ. Furthermore, an acrABtolC triple deletion strain was fully resistant to χ. Infection was severely reduced but not entirely blocked by the deletion of the gene tig encoding the molecular chaperone trigger factor. Finally, deletion in genes encoding enzymes involved in the synthesis of the antioxidants glutathione (GSH) and uric acid resulted in reduced infectivity. Our findings begin to elucidate poorly understood processes involved in later stages of flagellotropic bacteriophage infection and informs research aimed at the use of bacteriophages to combat antibiotic-resistant bacterial infections.IMPORTANCEAntimicrobial resistance is a large concern in the healthcare field. With more multi-drug resistant bacterial pathogens emerging, other techniques for eliminating bacterial infections are being explored. Among these is phage therapy, where combinations of specific phages are used to treat infections. Generally, phages utilize cell appendages and surface receptors for the initial attachment to their host. Phages that are flagellotropic are of particular interest because flagella are often important in bacterial virulence, making resistance to attachment of these phages harder to achieve without reducing virulence. This study discovered the importance of a multi-drug efflux pump for the infection of Salmonella enterica by a flagellotropic phage. In theory, if a bacterial pathogen develops phage resistance by altering expression of the efflux pump then the pathogen would simultaneously become more susceptible to the antibiotic substrates of the pump. Thus, co-administering antibiotics and flagellotropic phage may be a particularly potent antibacterial therapy.
Collapse
|
43
|
Mechanistic insights into synergy between nalidixic acid and tetracycline against clinical isolates of Acinetobacter baumannii and Escherichia coli. Commun Biol 2021; 4:542. [PMID: 33972678 PMCID: PMC8110569 DOI: 10.1038/s42003-021-02074-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 04/01/2021] [Indexed: 02/03/2023] Open
Abstract
The increasing prevalence of antimicrobial resistance has become a global health problem. Acinetobacter baumannii is an important nosocomial pathogen due to its capacity to persist in the hospital environment. It has a high mortality rate and few treatment options. Antibiotic combinations can help to fight multi-drug resistant (MDR) bacterial infections, but they are rarely used in the clinics and mostly unexplored. The interaction between bacteriostatic and bactericidal antibiotics are mostly reported as antagonism based on the results obtained in the susceptible model laboratory strain Escherichia coli. However, in the present study, we report a synergistic interaction between nalidixic acid and tetracycline against clinical multi-drug resistant A. baumannii and E. coli. Here we provide mechanistic insight into this dichotomy. The synergistic combination was studied by checkerboard assay and time-kill curve analysis. We also elucidate the mechanism behind this synergy using several techniques such as fluorescence spectroscopy, flow cytometry, fluorescence microscopy, morphometric analysis, and real-time polymerase chain reaction. Nalidixic acid and tetracycline combination displayed synergy against most of the MDR clinical isolates of A. baumannii and E. coli but not against susceptible isolates. Finally, we demonstrate that this combination is also effective in vivo in an A. baumannii/Caenorhabditis elegans infection model (p < 0.001).
Collapse
|
44
|
Moir DT, Opperman TJ, Aron ZD, Bowlin TL. Adjunctive therapy for multidrug-resistant bacterial infections: Type III secretion system and efflux inhibitors. Drug Discov Today 2021; 26:2173-2181. [PMID: 33845218 DOI: 10.1016/j.drudis.2021.03.031] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 03/21/2021] [Accepted: 03/31/2021] [Indexed: 10/21/2022]
Abstract
The increasing prevalence of multidrug-resistant (MDR) bacterial infections has created a crucial need for new therapeutics that avoid or minimize existing resistance mechanisms. In this review, we describe the development of novel classes of small-molecule adjunctive agents targeting either a bacterial virulence factor, the Pseudomonas aeruginosa type III secretion system (T3SS), or an intrinsic resistance factor, resistance-nodulation-cell division superfamily (RND) efflux pumps of the Enterobacteriaceae. These agents are designed to be administered with antibacterials to improve their efficacy. T3SS inhibition rescues host innate immune system cells from injection with bacterial toxins, whereas RND efflux pump inhibition increases antibiotic susceptibility, in both cases improving the efficacy of the combined antibacterial.
Collapse
|
45
|
Metabolomics Reveal Potential Natural Substrates of AcrB in Escherichia coli and Salmonella enterica Serovar Typhimurium. mBio 2021; 12:mBio.00109-21. [PMID: 33785633 PMCID: PMC8092203 DOI: 10.1128/mbio.00109-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Multidrug-resistant Gram-negative bacteria pose a global threat to human health. The AcrB efflux pump confers inherent and evolved drug resistance to Enterobacterales, including Escherichia coli and Salmonella enterica serovar Typhimurium. In the fight against antibiotic resistance, drugs that target resistance mechanisms in bacteria can be used to restore the therapeutic effectiveness of antibiotics. The multidrug resistance efflux complex AcrAB-TolC is the most clinically relevant efflux pump in Enterobacterales and is a target for drug discovery. Inhibition of the pump protein AcrB allows the intracellular accumulation of a wide variety of antibiotics, effectively restoring their therapeutic potency. To facilitate the development of AcrB efflux inhibitors, it is desirable to discover the native substrates of the pump, as these could be chemically modified to become inhibitors. We analyzed the native substrate profile of AcrB in Escherichia coli MG1655 and Salmonella enterica serovar Typhimurium SL1344 using an untargeted metabolomics approach. We analyzed the endo- and exometabolome of the wild-type strain and their respective AcrB loss-of-function mutants (AcrB D408A) to determine the metabolites that are native substrates of AcrB. Although there is 95% homology between the AcrB proteins of S. Typhimurium and E. coli, we observed mostly different metabolic responses in the exometabolomes of the S. Typhimurium and E. coli AcrB D408A mutants relative to those in the wild type, potentially indicating a differential metabolic adaptation to the same mutation in these two species. Additionally, we uncovered metabolite classes that could be involved in virulence of S. Typhimurium and a potential natural substrate of AcrB common to both species.
Collapse
|
46
|
Nobrega DB, Calarga AP, Nascimento LC, Chande Vasconcelos CG, de Lima EM, Langoni H, Brocchi M. Molecular characterization of antimicrobial resistance in Klebsiella pneumoniae isolated from Brazilian dairy herds. J Dairy Sci 2021; 104:7210-7224. [PMID: 33773789 DOI: 10.3168/jds.2020-19569] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 01/16/2021] [Indexed: 11/19/2022]
Abstract
In this observational study, phenotypic and genotypic patterns of antimicrobial resistance (AMR) in Klebsiella pneumoniae isolated from intramammary infections, clinical mastitis, fresh feces, rectal swabs, animal hindlimbs, and bulk tank milk samples from Brazilian dairy herds were investigated. In addition, we identified specific genetic variants present among extended-spectrum β-lactamase (ESBL) producers. We obtained 169 isolates of K. pneumoniae from 2009 to 2011 on 24 Brazilian dairy farms located in 4 Brazilian states. The AMR profile of all isolates was determined using disk-diffusion assays. The antimicrobial panel included drugs commonly used as mastitis treatment in Brazilian dairy herds (gentamicin, cephalosporins, sulfamethoxazole-trimethoprim, tetracycline) as well as antimicrobials of critical importance for human health (meropenem, ceftazidime, fluoroquinolones). The K. pneumoniae isolates resistant to tetracycline, fluoroquinolones, sulfamethoxazole-trimethoprim, or chloramphenicol were screened for presence of drug-specific AMR genes [tet, qnr, aac(6')-Ib, floR, catA2, cm1A, dfr, sul] using PCR. In addition, we identified ESBL genes present among ESBL-producers by using whole genome sequencing. Genomes were assembled and annotated, and patterns of AMR genes were investigated. Resistance was commonly detected against tetracycline (22.5% of all isolates), streptomycin (20.7%), and sulfamethoxazole-trimethoprim (9.5%). Antimicrobial resistance rates were higher in K. pneumoniae isolated from intramammary infections in comparison with isolates from feces (19.2 and 0% of multidrug resistance in intramammary and fecal isolates, respectively). In contrast, no difference in AMR rates was observed when contrasting hind limbs and isolates from intramammary infections. The genes tetA, sul2, and floR were the most frequently observed AMR genes in K. pneumoniae resistant to tetracycline, sulfamethoxazole-trimethoprim, and chloramphenicol, respectively. The tetA gene was present exclusively in isolates from milk. The genes blaCTX-M8 and blaSHV-108 were present in 3 ESBL-producing K. pneumoniae, including an isolate from bulk tank milk. The 3 isolates were of sequence type 281 and had similar mobile genetic elements and virulence genes. Our study reinforced the epidemiological importance and dissemination of blaCTX-M-8 pST114 plasmid in food-producing animals in Brazil.
Collapse
Affiliation(s)
- Diego Borin Nobrega
- Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, ON, N1G 2W1, Canada; Department of Genetics, Evolution, Microbiology and Immunology, Institute of Biology, University of Campinas (UNICAMP), 13083-650, Campinas, São Paulo, Brazil.
| | - Aline Parolin Calarga
- Department of Genetics, Evolution, Microbiology and Immunology, Institute of Biology, University of Campinas (UNICAMP), 13083-650, Campinas, São Paulo, Brazil
| | - Leandro Costa Nascimento
- Central Laboratory for High Performance Technologies (LaCTAD), University of Campinas (UNICAMP), 13083-886, Campinas, São Paulo, Brazil
| | | | | | - Helio Langoni
- Department of Veterinary Hygiene and Public Health, São Paulo State University (UNESP), 16618-681, Botucatu, São Paulo, Brazil
| | - Marcelo Brocchi
- Department of Genetics, Evolution, Microbiology and Immunology, Institute of Biology, University of Campinas (UNICAMP), 13083-650, Campinas, São Paulo, Brazil.
| |
Collapse
|
47
|
Chen SJ, Shu HY, Lin GH. Regulation of tert-Butyl Hydroperoxide Resistance by Chromosomal OhrR in A. baumannii ATCC 19606. Microorganisms 2021; 9:microorganisms9030629. [PMID: 33803549 PMCID: PMC8002998 DOI: 10.3390/microorganisms9030629] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 03/11/2021] [Accepted: 03/15/2021] [Indexed: 12/12/2022] Open
Abstract
In this study, we show that Acinetobacter baumannii ATCC 19606 harbors two sets of ohrR-ohr genes, respectively encoded in chromosomal DNA and a pMAC plasmid. We found no significant difference in organic hydroperoxide (OHP) resistance between strains with or without pMAC. However, a disk diffusion assay conducted by exposing wild-type, ∆ohrR-C, C represented gene on chromosome, or ∆ohr-C single mutants, or ∆ohrR-C∆ohr-C double mutants to tert-butyl hydroperoxide (tBHP) found that the ohrR-p-ohr-p genes, p represented genes on pMAC plasmid, may be able to complement the function of their chromosomal counterparts. Interestingly, ∆ohr-C single mutants generated in A. baumannii ATCC 17978, which does not harbor pMAC, demonstrated delayed exponential growth and loss of viability following exposure to 135 μg of tBHP. In a survival assay conducted with Galleria mellonella larvae, these mutants demonstrated almost complete loss of virulence. Via an electrophoretic mobility shift assay (EMSA), we found that OhrR-C was able to bind to the promoter regions of both chromosomal and pMAC ohr-p genes, but with varying affinity. A gain-of-function assay conducted in Escherichia coli showed that OhrR-C was not only capable of suppressing transformed ohr-C genes but may also repress endogenous enzymes. Taken together, our findings suggest that chromosomal ohrR-C-ohr-C genes act as the major system in protecting A. baumannii ATCC 19606 from OHP stresses, but the ohrR-p-ohr-p genes on pMAC can provide a supplementary protective effect, and the interaction between these genes may affect other aspects of bacterial viability, such as growth and virulence.
Collapse
Affiliation(s)
- Shih-Jie Chen
- Master Program in Microbiology and Immunology, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan;
| | - Hung-Yu Shu
- Department of Bioscience Technology, Chang Jung Christian University, Tainan 71101, Taiwan;
| | - Guang-Huey Lin
- Master Program in Microbiology and Immunology, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan;
- International College, Tzu Chi University, Hualien 97004, Taiwan
- Correspondence: or
| |
Collapse
|
48
|
Youlden GH, Ricci V, Wang-Kan X, Piddock LJV, Jabbari S, King JR. Time dependent asymptotic analysis of the gene regulatory network of the AcrAB-TolC efflux pump system in gram-negative bacteria. J Math Biol 2021; 82:31. [PMID: 33694073 PMCID: PMC7946726 DOI: 10.1007/s00285-021-01576-4] [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: 11/20/2019] [Revised: 07/27/2020] [Accepted: 02/14/2021] [Indexed: 12/12/2022]
Abstract
Efflux pumps are a mechanism of intrinsic and evolved resistance in bacteria. If an efflux pump can expel an antibiotic so that its concentration within the cell is below a killing threshold the bacteria are resistant to the antibiotic. Efflux pumps may be specific or they may pump various different substances. This is why many efflux pumps confer multi drug resistance (MDR). In particular over expression of the AcrAB−TolC efflux pump system confers MDR in both Salmonella and Escherichia coli. We consider the complex gene regulation network that controls expression of genes central to controlling the efflux associated genes acrAB and acrEF in Salmonella. We present the first mathematical model of this gene regulatory network in the form of a system of ordinary differential equations. Using a time dependent asymptotic analysis, we examine in detail the behaviour of the efflux system on various different timescales. Asymptotic approximations of the steady states provide an analytical comparison of targets for efflux inhibition.
Collapse
Affiliation(s)
- George H Youlden
- School of Mathematics, University of Birmingham, Birmingham, B15 2TT, UK. .,School of Mathematical Sciences, University of Nottingham, Nottingham, NG7 2RD, UK. .,Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK.
| | - Vito Ricci
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK
| | - Xuan Wang-Kan
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK.,Gyrd-Hansen Group, Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7DQ, UK
| | - Laura J V Piddock
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK
| | - Sara Jabbari
- School of Mathematics, University of Birmingham, Birmingham, B15 2TT, UK.,Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK
| | - John R King
- School of Mathematical Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| |
Collapse
|
49
|
Bismuth HD, Brasseur G, Ezraty B, Aussel L. Bacterial Genetic Approach to the Study of Reactive Oxygen Species Production in Galleria mellonella During Salmonella Infection. Front Cell Infect Microbiol 2021; 11:640112. [PMID: 33732665 PMCID: PMC7957066 DOI: 10.3389/fcimb.2021.640112] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 01/13/2021] [Indexed: 11/21/2022] Open
Abstract
Over the last decade, an increasing number of reports presented Galleria mellonella larvae as an important model to study host-pathogen interactions. Coherently, increasing information became available about molecular mechanisms used by this host to cope with microbial infections but few of them dealt with oxidative stress. In this work, we addressed the role of reactive oxygen species (ROS) produced by the immune system of G. mellonella to resist against Salmonella enterica, an intracellular pathogen responsible for a wide range of infections. We confirmed that Salmonella was pathogen for G. mellonella and showed that it had to reach a minimal bacterial load within the hemolymph to kill the larvae. ROS production by G. mellonella was revealed by the virulence defects of Salmonella mutants lacking catalases/peroxiredoxins or cytoplasmic superoxide dismutases, both strains being highly sensitive to these oxidants. Finally, we used bacterial transcriptional fusions to demonstrate that hydrogen peroxide (H2O2) was produced in the hemolymph of Galleria during infection and sensed by S. enterica. In line with this observation, the H2O2-dependent regulator OxyR was found to be required for bacterial virulence in the larvae. These results led us to conclude that ROS production is an important mechanism used by G. mellonella to counteract bacterial infections and validate this host as a relevant model to study host-pathogen interactions.
Collapse
Affiliation(s)
- Hanna D Bismuth
- Aix-Marseille Université, CNRS, Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Gaël Brasseur
- Aix-Marseille Université, CNRS, Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Benjamin Ezraty
- Aix-Marseille Université, CNRS, Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Laurent Aussel
- Aix-Marseille Université, CNRS, Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, Marseille, France
| |
Collapse
|
50
|
Genomic Analysis of Natural Rough Brucella melitensis Rev.1 Vaccine Strains: Identification and Characterization of Mutations in Key Genes Associated with Bacterial LPS Biosynthesis and Virulence. Int J Mol Sci 2020; 21:ijms21249341. [PMID: 33302421 PMCID: PMC7762576 DOI: 10.3390/ijms21249341] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/02/2020] [Accepted: 12/03/2020] [Indexed: 11/22/2022] Open
Abstract
Brucella species are facultative intracellular bacteria that cause brucellosis, a zoonotic world-wide disease. The live attenuated B. melitensis Rev.1 vaccine strain is widely used for the control of brucellosis in the small ruminant population. However, Rev.1 induces antibodies against the O-polysaccharide (O-PS) of the smooth lipopolysaccharide thus, it is difficult to differentiate between infected and vaccinated animals. Hence, rough Brucella strains lacking the O-PS have been introduced. In the current study, we conducted a comprehensive comparative analysis of the genome sequence of two natural Rev.1 rough strains, isolated from sheep, against that of 24 Rev.1 smooth strains and the virulent reference strain B. melitensis 16M. We identified and characterized eight vital mutations within highly important genes associated with Brucella lipopolysaccharide (LPS) biosynthesis and virulence, which may explain the mechanisms underlying the formation of the Rev.1 rough phenotype and may be used to determine the mechanism underlying virulence attenuation. Further complementation studies aimed to estimate the specific role of these mutations in affecting Brucella morphology and virulence will serve as a basis for the design of new attenuated vaccines for animal immunization against brucellosis.
Collapse
|