1
|
Lee T, Lee S, Kim MK, Ahn JH, Park JS, Seo HW, Park KH, Chong Y. 3- O-Substituted Quercetin: an Antibiotic-Potentiating Agent against Multidrug-Resistant Gram-Negative Enterobacteriaceae through Simultaneous Inhibition of Efflux Pump and Broad-Spectrum Carbapenemases. ACS Infect Dis 2024; 10:1624-1643. [PMID: 38652574 DOI: 10.1021/acsinfecdis.3c00715] [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] [Indexed: 04/25/2024]
Abstract
The discovery of safe and efficient inhibitors against efflux pumps as well as metallo-β-lactamases (MBL) is one of the main challenges in the development of multidrug-resistant (MDR) reversal agents which can be utilized in the treatment of carbapenem-resistant Gram-negative bacteria. In this study, we have identified that introduction of an ethylene-linked sterically demanding group at the 3-OH position of the previously reported MDR reversal agent di-F-Q endows the resulting compounds with hereto unknown multitarget inhibitory activity against both efflux pumps and broad-spectrum β-lactamases including difficult-to-inhibit MBLs. A molecular docking study of the multitarget inhibitors against efflux pump, as well as various classes of β-lactamases, revealed that the 3-O-alkyl substituents occupy the novel binding sites in efflux pumps as well as carbapenemases. Not surprisingly, the multitarget inhibitors rescued the antibiotic activity of a carbapenem antibiotic, meropenem (MEM), in NDM-1 (New Delhi Metallo-β-lactamase-1)-producing carbapenem-resistant Enterobacteriaceae (CRE), and they reduced MICs of MEM more than four-fold (synergistic effect) in 8-9 out of 14 clinical strains. The antibiotic-potentiating activity of the multitarget inhibitors was also demonstrated in CRE-infected mouse model. Taken together, these results suggest that combining inhibitory activity against two critical targets in MDR Gram-negative bacteria, efflux pumps, and β-lactamases, in one molecule is possible, and the multitarget inhibitors may provide new avenues for the discovery of safe and efficient MDR reversal agents.
Collapse
Affiliation(s)
- Taegum Lee
- Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Hwayang-dong, Gwangjin-gu, Seoul 05029, Korea
| | - Seongyeon Lee
- Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Hwayang-dong, Gwangjin-gu, Seoul 05029, Korea
| | - Mi Kyoung Kim
- Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Hwayang-dong, Gwangjin-gu, Seoul 05029, Korea
| | - Joong Hoon Ahn
- Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Hwayang-dong, Gwangjin-gu, Seoul 05029, Korea
| | - Ji Sun Park
- Infectious Disease Research Center, Korea Research Institute of Bioscience & Biotechnology, Yuseong-gu, Daejeon 34141, Korea
| | - Hwi Won Seo
- Infectious Disease Research Center, Korea Research Institute of Bioscience & Biotechnology, Yuseong-gu, Daejeon 34141, Korea
| | - Ki-Ho Park
- Department of Infectious Disease, Kyung Hee University School of Medicine, Seoul 02447, Korea
| | - Youhoon Chong
- Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Hwayang-dong, Gwangjin-gu, Seoul 05029, Korea
| |
Collapse
|
2
|
Saini M, Gaurav A, Hussain A, Pathania R. Small Molecule IITR08367 Potentiates Antibacterial Efficacy of Fosfomycin against Acinetobacter baumannii by Efflux Pump Inhibition. ACS Infect Dis 2024; 10:1711-1724. [PMID: 38562022 DOI: 10.1021/acsinfecdis.4c00077] [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] [Indexed: 04/04/2024]
Abstract
Fosfomycin is a broad-spectrum single-dose therapy approved for treating lower urinary tract infections. Acinetobacter baumannii, one of the five major UTI-causing pathogens, is intrinsically resistant to fosfomycin. Reduced uptake and active efflux are major reasons for this intrinsic resistance. AbaF, a major facilitator superfamily class of transporter in A. baumannii, is responsible for fosfomycin efflux and biofilm formation. This study describes the identification and validation of a novel small-molecule efflux pump inhibitor that potentiates fosfomycin efficacy against A. baumannii. An AbaF inhibitor screening was performed against Escherichia coli KAM32/pUC18_abaF, using the noninhibitory concentration of 24 putative efflux pump inhibitors. The inhibitory activity of IITR08367 [bis(4-methylbenzyl) disufide] against fosfomycin/H+ antiport was validated using ethidium bromide efflux, quinacrine-based proton-sensitive fluorescence, and membrane depolarization assays. IITR08367 inhibits fosfomycin/H+ antiport activity by perturbing the transmembrane proton gradient. IITR08367 is a nontoxic molecule that potentiates fosfomycin activity against clinical strains of A. baumannii and prevents biofilm formation by inhibiting efflux pump (AbaF). The IITR08367-fosfomycin combination reduced bacterial burden by > 3 log10 in kidney and bladder tissue in the murine UTI model. Overall, fosfomycin, in combination with IITR08367, holds the potential to treat urinary tract infections caused by A. baumannii.
Collapse
Affiliation(s)
- Mahak Saini
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Roorkee, Uttarakhand 247 667, India
| | - Amit Gaurav
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Roorkee, Uttarakhand 247 667, India
| | - Arsalan Hussain
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Roorkee, Uttarakhand 247 667, India
| | - Ranjana Pathania
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Roorkee, Uttarakhand 247 667, India
| |
Collapse
|
3
|
Mukhopadhyay S, Bishayi R, Shaji A, Lee AH, Gupta R, Mohajeri M, Katiyar A, McKee B, Schmitz IR, Shin R, Lele TP, Lele PP. Dynamic Adaptation in Extant Porins Facilitates Antibiotic Tolerance in Energetic Escherichia coli. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.07.583920. [PMID: 38496420 PMCID: PMC10942424 DOI: 10.1101/2024.03.07.583920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Bacteria can tolerate antibiotics despite lacking the genetic components for resistance. The prevailing notion is that tolerance results from depleted cellular energy or cell dormancy. In contrast to this view, many cells in the tolerant population of Escherichia coli can exhibit motility - a phenomenon that requires cellular energy, specifically, the proton-motive force (PMF). As these motile-tolerant cells are challenging to isolate from the heterogeneous tolerant population, their survival mechanism is unknown. Here, we discovered that motile bacteria segregate themselves from the tolerant population under micro-confinement, owing to their unique ability to penetrate micron-sized channels. Single-cell measurements on the motile-tolerant population showed that the cells retained a high PMF, but they did not survive through active efflux alone. By utilizing growth assays, single-cell fluorescence studies, and chemotaxis assays, we showed that the cells survived by dynamically inhibiting the function of existing porins in the outer membrane. A drug transport model for porin-mediated intake and efflux pump-mediated expulsion suggested that energetic tolerant cells withstand antibiotics by constricting their porins. The novel porin adaptation we have uncovered is independent of gene expression changes and may involve electrostatic modifications within individual porins to prevent extracellular ligand entry.
Collapse
|
4
|
Shenoy V, Gunda R, Noble C, Haraguchi A, Stevenson S, Daniel J. Fullertubes inhibit mycobacterial viability and prevent biofilm formation by disrupting the cell wall. Cell Biochem Funct 2024; 42:e3963. [PMID: 38424684 DOI: 10.1002/cbf.3963] [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: 09/21/2023] [Revised: 01/31/2024] [Accepted: 02/21/2024] [Indexed: 03/02/2024]
Abstract
Mycobacterium tuberculosis and nontuberculous mycobacteria such as Mycobacterium abscessus cause diseases that are becoming increasingly difficult to treat due to emerging antibiotic resistance. The development of new antimicrobial molecules is vital for combating these pathogens. Carbon nanomaterials (CNMs) are a class of carbon-containing nanoparticles with promising antimicrobial effects. Fullertubes (C90 ) are novel carbon allotropes with a structure unique among CNMs. The effects of fullertubes on any living cell have not been studied. In this study, we demonstrate that pristine fullertube dispersions show antimicrobial effects on Mycobacterium smegmatis and M. abscessus. Using scanning electron microscopy, light microscopy, and molecular probes, we investigated the effects of these CNMs on mycobacterial cell viability, cellular integrity, and biofilm formation. C90 fullertubes at 1 µM inhibited mycobacterial viability by 97%. Scanning electron microscopy revealed that the cell wall structure of M. smegmatis and M. abscessus was severely damaged within 24 h of exposure to fullertubes. Additionally, exposure to fullertubes nearly abrogated the acid-fast staining property of M. smegmatis. Using SYTO-9 and propidium iodide, we show that exposure to the novel fullertubes compromises the integrity of the mycobacterial cell. We also show that the permeability of the mycobacterial cell wall was increased after exposure to fullertubes from our assays utilizing the molecular probe dichlorofluorescein and ethidium bromide transport. C90 fullertubes at 0.37 µM and C60 fullerenes at 0.56 µM inhibited pellicle biofilm formation by 70% and 90%, respectively. This is the first report on the antimycobacterial activities of fullertubes and fullerenes.
Collapse
Affiliation(s)
- Varun Shenoy
- Department of Biological Sciences, Purdue University Fort Wayne, Fort Wayne, Indiana, USA
- Department of Chemistry and Biochemistry, Purdue University Fort Wayne, Fort Wayne, Indiana, USA
| | - Rashmika Gunda
- Department of Biological Sciences, Purdue University Fort Wayne, Fort Wayne, Indiana, USA
| | - Cora Noble
- Department of Chemistry and Biochemistry, Purdue University Fort Wayne, Fort Wayne, Indiana, USA
| | - Annalisa Haraguchi
- Department of Biological Sciences, Purdue University Fort Wayne, Fort Wayne, Indiana, USA
| | - Steven Stevenson
- Department of Chemistry and Biochemistry, Purdue University Fort Wayne, Fort Wayne, Indiana, USA
| | - Jaiyanth Daniel
- Department of Biological Sciences, Purdue University Fort Wayne, Fort Wayne, Indiana, USA
| |
Collapse
|
5
|
Chamlagain M, Hu J, Sionov RV, Steinberg D. Anti-bacterial and anti-biofilm activities of arachidonic acid against the cariogenic bacterium Streptococcus mutans. Front Microbiol 2024; 15:1333274. [PMID: 38596377 PMCID: PMC11002910 DOI: 10.3389/fmicb.2024.1333274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Accepted: 02/16/2024] [Indexed: 04/11/2024] Open
Abstract
Streptococcus mutans is a Gram-positive, facultative anaerobic bacterium, which causes dental caries after forming biofilms on the tooth surface while producing organic acids that demineralize enamel and dentin. We observed that the polyunsaturated arachidonic acid (AA) (ω-6; 20:4) had an anti-bacterial activity against S. mutans, which prompted us to investigate its mechanism of action. The minimum inhibitory concentration (MIC) of AA on S. mutans was 25 μg/ml in the presence of 5% CO2, while it was reduced to 6.25-12.5 μg/ml in the absence of CO2 supplementation. The anti-bacterial action was due to a combination of bactericidal and bacteriostatic effects. The minimum biofilm inhibitory concentration (MBIC) was the same as the MIC, suggesting that part of the anti-biofilm effect was due to the anti-bacterial activity. Gene expression studies showed decreased expression of biofilm-related genes, suggesting that AA also has a specific anti-biofilm effect. Flow cytometric analyses using potentiometric DiOC2(3) dye, fluorescent efflux pump substrates, and live/dead SYTO 9/propidium iodide staining showed that AA leads to immediate membrane hyperpolarization, altered membrane transport and efflux pump activities, and increased membrane permeability with subsequent membrane perforation. High-resolution scanning electron microscopy (HR-SEM) showed remnants of burst bacteria. Furthermore, flow cytometric analysis using the redox probe 2',7'-dichlorofluorescein diacetate (DCFHDA) showed that AA acts as an antioxidant in a dose-dependent manner. α-Tocopherol, an antioxidant that terminates the radical chain, counteracted the anti-bacterial activity of AA, suggesting that oxidation of AA in bacteria leads to the production of cytotoxic radicals that contribute to bacterial growth arrest and death. Importantly, AA was not toxic to normal Vero epithelial cells even at 100 μg/ml, and it did not cause hemolysis of erythrocytes. In conclusion, our study shows that AA is a potentially safe drug that can be used to reduce the bacterial burden of cariogenic S. mutans.
Collapse
Affiliation(s)
- Manoj Chamlagain
- Institute of Biomedical and Oral Research (IBOR), The Faculty of Dental Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Jieni Hu
- Institute of Biomedical and Oral Research (IBOR), The Faculty of Dental Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Ronit Vogt Sionov
- Institute of Biomedical and Oral Research (IBOR), The Faculty of Dental Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Doron Steinberg
- Institute of Biomedical and Oral Research (IBOR), The Faculty of Dental Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| |
Collapse
|
6
|
Chatterjee D, Panda AP, Daya Manasi AR, Ghosh AS. P-type ATPase zinc transporter Rv3270 of Mycobacterium tuberculosis enhances multi-drug efflux activity. MICROBIOLOGY (READING, ENGLAND) 2024; 170:001441. [PMID: 38373028 PMCID: PMC10924464 DOI: 10.1099/mic.0.001441] [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: 08/14/2023] [Accepted: 02/08/2024] [Indexed: 02/20/2024]
Abstract
Metal homeostasis is maintained by the uptake, storage and efflux of metal ions that are necessary for the survival of the bacterium. Homeostasis is mostly regulated by a group of transporters categorized as ABC transporters and P-type ATPases. On the other hand, efflux pumps often play a role in drug-metal cross-resistance. Here, with the help of antibiotic sensitivity, antibiotic/dye accumulation and semi-quantitative biofilm formation assessments we report the ability of Rv3270, a P-type ATPase known for its role in combating Mn2+ and Zn2+ metal ion toxicity in Mycobacterium tuberculosis, in influencing the extrusion of multiple structurally unrelated drugs and enhancing the biofilm formation of Escherichia coli and Mycobacterium smegmatis. Overexpression of Rv3270 increased the tolerance of host cells to norfloxacin, ofloxacin, sparfloxacin, ampicillin, oxacillin, amikacin and isoniazid. A significantly lower accumulation of norfloxacin, ethidium bromide, bocillin FL and levofloxacin in cells harbouring Rv3270 as compared to host cells indicated its role in enhancing efflux activity. Although over-expression of Rv3270 did not alter the susceptibility levels of levofloxacin, rifampicin and apramycin, the presence of a sub-inhibitory concentration of Zn2+ resulted in low-level tolerance towards these drugs. Of note, the expression of Rv3270 enhanced the biofilm-forming ability of the host cells strengthening its role in antimicrobial resistance. Therefore, the study indicated that the over-expression of Rv3270 enhances the drug efflux activity of the micro-organism where zinc might facilitate drug-metal cross-resistance for some antibiotics.
Collapse
Affiliation(s)
- Debasmita Chatterjee
- Department of Bioscience and Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Aditya Prasad Panda
- Department of Bioscience and Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - A. R. Daya Manasi
- Department of Bioscience and Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Anindya S. Ghosh
- Department of Bioscience and Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| |
Collapse
|
7
|
Santos AL, Liu D, van Venrooy A, Beckham JL, Oliver A, Tegos GP, Tour JM. Nonlethal Molecular Nanomachines Potentiate Antibiotic Activity Against Gram-Negative Bacteria by Increasing Cell Permeability and Attenuating Efflux. ACS NANO 2024; 18:3023-3042. [PMID: 38241477 DOI: 10.1021/acsnano.3c08041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2024]
Abstract
Antibiotic resistance is a pressing public health threat. Despite rising resistance, antibiotic development, especially for Gram-negative bacteria, has stagnated. As the traditional antibiotic research and development pipeline struggles to address this growing concern, alternative solutions become imperative. Synthetic molecular nanomachines (MNMs) are molecular structures that rotate unidirectionally in a controlled manner in response to a stimulus, such as light, resulting in a mechanical action that can propel molecules to drill into cell membranes, causing rapid cell death. Due to their broad destructive capabilities, clinical translation of MNMs remains challenging. Hence, here, we explore the ability of nonlethal visible-light-activated MNMs to potentiate conventional antibiotics against Gram-negative bacteria. Nonlethal MNMs enhanced the antibacterial activity of various classes of conventional antibiotics against Gram-negative bacteria, including those typically effective only against Gram-positive strains, reducing the antibiotic concentration required for bactericidal action. Our study also revealed that MNMs bind to the negatively charged phospholipids of the bacterial inner membrane, leading to permeabilization of the cell envelope and impairment of efflux pump activity following light activation of MNMs. The combined effects of MNMs on membrane permeability and efflux pumps resulted in increased antibiotic accumulation inside the cell, reversing antibiotic resistance and attenuating its development. These results identify nonlethal MNMs as pleiotropic antibiotic enhancers or adjuvants. The combination of MNMs with traditional antibiotics is a promising strategy against multidrug-resistant Gram-negative infections. This approach can reduce the amount of antibiotics needed and slow down antibiotic resistance development, thereby preserving the effectiveness of our current antibiotics.
Collapse
Affiliation(s)
- Ana L Santos
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
- IdISBA - Fundación de Investigación Sanitaria de las Islas Baleares, 07120 Palma, Spain
| | - Dongdong Liu
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Alexis van Venrooy
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Jacob L Beckham
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Antonio Oliver
- IdISBA - Fundación de Investigación Sanitaria de las Islas Baleares, 07120 Palma, Spain
- Servicio de Microbiologia, Hospital Universitari Son Espases, 07120 Palma, Spain
- Centro de Investigación Biomédica en Red, Enfermedades Infecciosas (CIBERINFEC), Av. Monforte de Lemos 3-5, 28029 Madrid, Spain
| | - George P Tegos
- Office of Research, Faxton St. Luke's Healthcare, Mohawk Valley Health System, 1676 Sunset Avenue, Utica, New York 13502, United States
| | - James M Tour
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
- Smalley-Curl Institute, Rice University, Houston, Texas 77005, United States
- Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
- NanoCarbon Center and Rice Advanced Materials Institute, Rice University, Houston, Texas 77005, United States
| |
Collapse
|
8
|
Lee S, Lee T, Kim MK, Ahn JH, Jeong S, Park KH, Chong Y. Potentiation of Antibiotic Activity of Aztreonam against Metallo-β-Lactamase-Producing Multidrug-Resistant Pseudomonas aeruginosa by 3- O-Substituted Difluoroquercetin Derivatives. Pharmaceutics 2024; 16:185. [PMID: 38399246 PMCID: PMC10892423 DOI: 10.3390/pharmaceutics16020185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 01/24/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024] Open
Abstract
The combination of aztreonam (ATM) and ceftazidime-avibactam (CAZ-AVI; CZA) has shown therapeutic potential against serine-β-lactamase (SBL)- and metallo-β-lactamase (MBL)-producing Enterobacterales. However, the ability of CZA to restore the antibiotic activity of ATM is severely limited in MBL-producing multidrug-resistant (MDR) Pseudomonas aeruginosa strains because of the myriad of intrinsic and acquired resistance mechanisms associated with this pathogen. We reasoned that the simultaneous inhibition of multiple targets associated with multidrug resistance mechanisms may potentiate the antibiotic activity of ATM against MBL-producing P. aeruginosa. During a search for the multitarget inhibitors through a molecular docking study, we discovered that di-F-Q, the previously reported efflux pump inhibitor of MDR P. aeruginosa, binds to the active sites of the efflux pump (MexB), as well as various β-lactamases, and these sites are open to the 3-O-position of di-F-Q. The 3-O-substituted di-F-Q derivatives were thus synthesized and showed hereto unknown multitarget MDR inhibitory activity against various ATM-hydrolyzing β-lactamases (AmpC, KPC, and New Delhi metallo-β-lactamase (NDM)) and the efflux pump of P. aeruginosa, presumably by forming additional hydrophobic contacts with the targets. The multitarget MDR inhibitor 27 effectively potentiated the antimicrobial activity of ATM and reduced the MIC of ATM more than four-fold in 19 out of 21 MBL-producing P. aeruginosa clinical strains, including the NDM-producing strains which were highly resistant to various combinations of ATM with β-lactamase inhibitors and/or efflux pump inhibitors. Our findings suggest that the simultaneous inhibition of multiple MDR targets might provide new avenues for the discovery of safe and efficient MDR reversal agents which can be used in combination with ATM against MBL-producing MDR P. aeruginosa.
Collapse
Affiliation(s)
- Seongyeon Lee
- Department of Bioscience and Biotechnology, Konkuk University, Hwayang-dong, Gwangjin-gu, Seoul 05029, Republic of Korea; (S.L.); (T.L.)
- Bio/Molecular Informatics Center, Konkuk University, Hwayang-dong, Gwangjin-gu, Seoul 05029, Republic of Korea; (M.K.K.); (J.H.A.)
| | - Taegum Lee
- Department of Bioscience and Biotechnology, Konkuk University, Hwayang-dong, Gwangjin-gu, Seoul 05029, Republic of Korea; (S.L.); (T.L.)
- Bio/Molecular Informatics Center, Konkuk University, Hwayang-dong, Gwangjin-gu, Seoul 05029, Republic of Korea; (M.K.K.); (J.H.A.)
| | - Mi Kyoung Kim
- Bio/Molecular Informatics Center, Konkuk University, Hwayang-dong, Gwangjin-gu, Seoul 05029, Republic of Korea; (M.K.K.); (J.H.A.)
| | - Joong Hoon Ahn
- Bio/Molecular Informatics Center, Konkuk University, Hwayang-dong, Gwangjin-gu, Seoul 05029, Republic of Korea; (M.K.K.); (J.H.A.)
- Department of Integrative Bioscience and Biotechnology, Konkuk University, Hwayang-dong, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Seri Jeong
- Department of Laboratory Medicine, Hallym University College of Medicine, Chuncheon 24252, Republic of Korea;
| | - Ki-Ho Park
- Department of Infectious Disease, Kyung Hee University School of Medicine, Seoul 02447, Republic of Korea
| | - Youhoon Chong
- Bio/Molecular Informatics Center, Konkuk University, Hwayang-dong, Gwangjin-gu, Seoul 05029, Republic of Korea; (M.K.K.); (J.H.A.)
- Department of Integrative Bioscience and Biotechnology, Konkuk University, Hwayang-dong, Gwangjin-gu, Seoul 05029, Republic of Korea
| |
Collapse
|
9
|
Ika Irianti M, Vincken JP, van Dinteren S, Ter Beest E, Pos KM, Araya-Cloutier C. Prenylated isoflavonoids from Fabaceae against the NorA efflux pump in Staphylococcus aureus. Sci Rep 2023; 13:22548. [PMID: 38110428 PMCID: PMC10728173 DOI: 10.1038/s41598-023-48992-8] [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: 08/25/2023] [Accepted: 12/02/2023] [Indexed: 12/20/2023] Open
Abstract
Overexpression of NorA efflux pumps plays a pivotal role in the multidrug-resistance mechanism in S. aureus. Here, we investigated the activities of prenylated isoflavonoids, present in the legume plant family (Fabaceae), as natural efflux pump inhibitors (EPIs) in fluoroquinolone-resistant S. aureus. We found that four prenylated isoflavonoids, namely neobavaisoflavone, glabrene, glyceollin I, and glyceollin III, showed efflux pump inhibition in the norA overexpressing S. aureus. At sub-inhibitory concentrations, neobavaisoflavone (6.25 µg/mL, 19 µM) and glabrene (12.5 µg/mL, 39 µM), showed up to 6 times more Eth accumulation in norA overexpressing S. aureus than in the control. In addition, these two compounds boosted the MIC of fluoroquinolones up to eightfold. No fluoroquinolone potentiation was observed with these isoflavonoids in the norA knockout strain, indicating NorA as the main target of these potential EPIs. In comparison to the reported NorA EPI reserpine, neobavaisoflavone showed similar potentiation of fluoroquinolone activity at 10 µM, higher Eth accumulation, and less cytotoxicity. Neobavaisoflavone and glabrene did not exhibit membrane permeabilization effects or cytotoxicity on Caco-2 cells. In conclusion, our findings suggest that the prenylated isoflavonoids neobavaisoflavone and glabrene are promising phytochemicals that could be developed as antimicrobials and resistance-modifying agents to treat fluoroquinolone-resistant S. aureus strains.
Collapse
Affiliation(s)
- Marina Ika Irianti
- Laboratory of Food Chemistry, Wageningen University and Research, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands
- Laboratory of Microbiology and Biotechnology, Faculty of Pharmacy, Universitas Indonesia, Depok, 16424, Indonesia
| | - Jean-Paul Vincken
- Laboratory of Food Chemistry, Wageningen University and Research, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands
| | - Sarah van Dinteren
- Laboratory of Food Chemistry, Wageningen University and Research, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands
| | - Ellen Ter Beest
- Laboratory of Food Chemistry, Wageningen University and Research, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands
| | - Klaas Martinus Pos
- Institute of Biochemistry, Goethe-University Frankfurt, 60438, Frankfurt am Main, Germany
| | - Carla Araya-Cloutier
- Laboratory of Food Chemistry, Wageningen University and Research, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands.
| |
Collapse
|
10
|
Rattanachak N, Weawsiangsang S, Baldock RA, Jaifoo T, Jongjitvimol T, Jongjitwimol J. A Novel and Quantitative Detection Assay ( effluxR) for Identifying Efflux-Associated Resistance Genes Using Multiplex Digital PCR in Clinical Isolates of Pseudomonas aeruginosa. Methods Protoc 2023; 6:96. [PMID: 37888028 PMCID: PMC10608825 DOI: 10.3390/mps6050096] [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: 08/21/2023] [Revised: 09/26/2023] [Accepted: 10/05/2023] [Indexed: 10/28/2023] Open
Abstract
The rise of multidrug resistance of Pseudomonas aeruginosa highlights an increased need for selective and precise antimicrobial treatment. Drug efflux pumps are one of the major mechanisms of antimicrobial resistance found in many bacteria, including P. aeruginosa. Detection of efflux genes using a polymerase chain reaction (PCR)-based system would enable resistance detection and aid clinical decision making. Therefore, we aimed to develop and optimize a novel method herein referred to as "effluxR detection assay" using multiplex digital PCR (mdPCR) for detection of mex efflux pump genes in P. aeruginosa strains. The annealing/extension temperatures and gDNA concentrations were optimized to amplify mexB, mexD, and mexY using the multiplex quantitative PCR (mqPCR) system. We established the optimal mqPCR conditions for the assay (Ta of 59 °C with gDNA concentrations at or above 0.5 ng/µL). Using these conditions, we were able to successfully detect the presence of these genes in a quantity-dependent manner. The limit of detection for mex genes using the effluxR detection assay with mdPCR was 0.001 ng/µL (7.04-34.81 copies/µL). Moreover, using blind sample testing, we show that effluxR detection assay had 100% sensitivity and specificity for detecting mex genes in P. aeruginosa. In conclusion, the effluxR detection assay, using mdPCR, is able to identify the presence of multiple mex genes in P. aeruginosa that may aid clinical laboratory decisions and further epidemiological studies.
Collapse
Affiliation(s)
- Nontaporn Rattanachak
- Biomedical Sciences Program, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok 65000, Thailand; (N.R.); (S.W.)
| | - Sattaporn Weawsiangsang
- Biomedical Sciences Program, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok 65000, Thailand; (N.R.); (S.W.)
| | - Robert A. Baldock
- School of Pharmacy and Biomedical Sciences, Faculty of Science and Health, University of Portsmouth, Portsmouth PO1 2DT, UK;
| | - Theerasak Jaifoo
- Master of Science Program in Medical Technology, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok 65000, Thailand;
| | - Touchkanin Jongjitvimol
- Biology Program, Faculty of Science and Technology, Pibulsongkram Rajabhat University, Phitsanulok 65000, Thailand
| | - Jirapas Jongjitwimol
- Department of Medical Technology, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok 65000, Thailand
- Centre of Excellence in Biomaterials, Faculty of Science, Naresuan University, Phitsanulok 65000, Thailand
| |
Collapse
|
11
|
Abu Ghazal T, Veres K, Vidács L, Szemerédi N, Spengler G, Berkecz R, Hohmann J. Furanonaphthoquinones, Diterpenes, and Flavonoids from Sweet Marjoram and Investigation of Antimicrobial, Bacterial Efflux, and Biofilm Formation Inhibitory Activities. ACS OMEGA 2023; 8:34816-34825. [PMID: 37780020 PMCID: PMC10536869 DOI: 10.1021/acsomega.3c03982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 09/01/2023] [Indexed: 10/03/2023]
Abstract
The chloroform extract of Origanum majorana exhibited high antibacterial and antifungal activities against 12 bacterial and 4 fungal strains; therefore, it was subjected to bioassay-guided isolation to afford six compounds (1-6). The structures were determined via one- and two-dimensional nuclear magnetic spectroscopy and high-resolution electrospray ionization mass spectrometry experiments. The compounds were identified as furanonaphthoquinones [majoranaquinone (1), 2,3-dimethylnaphtho[2,3-b]furan-4,9-dione (2)], diterpenes [19-hydroxyabieta-8,11,13-trien-7-one (3), 13,14-seco-13-oxo-19-hydroxyabieta-8-en-14-al (4)], and flavonoids [sterubin (5) and majoranin (6)]. Compounds 1 and 2 were first obtained from a natural source and compounds 3 and 4 were previously undescribed. Majoranaquinone (1) exhibited a high antibacterial effect against 4 Staphylococcus, 1 Moraxella, and 1 Enterococcus strains (MIC values between 7.8 μM and 1 mM). In the efflux pump inhibition assay, majoranaquinone (1) showed substantial activity in Escherichia coli ATCC 25922 strain. Furthermore, 1 was found to be an effective biofilm formation inhibitor on E. coli ATCC 25922 and E. coli K-12 AG100 bacteria. Our findings proved that bioactivities of majoranaquinone (1) significantly exceed those of the essential oil constituents; therefore, it should also be considered when assessing the antimicrobial effects of O. majorana.
Collapse
Affiliation(s)
| | - Katalin Veres
- Institute
of Pharmacognosy, University of Szeged, Szeged H-6720, Hungary
| | - Lívia Vidács
- Institute
of Pharmacognosy, University of Szeged, Szeged H-6720, Hungary
| | - Nikoletta Szemerédi
- Department
of Medical Microbiology, Albert Szent-Györgyi Health Center
and Albert Szent-Györgyi Medical School, University of Szeged, Szeged H-6720, Hungary
| | - Gabriella Spengler
- Department
of Medical Microbiology, Albert Szent-Györgyi Health Center
and Albert Szent-Györgyi Medical School, University of Szeged, Szeged H-6720, Hungary
| | - Róbert Berkecz
- Institute
of Pharmaceutical Analysis, University of
Szeged, 6720 Szeged, Hungary
| | - Judit Hohmann
- Institute
of Pharmacognosy, University of Szeged, Szeged H-6720, Hungary
- Interdisciplinary
Centre for Natural Products, University
of Szeged, Szeged H-6720, Hungary
- ELKH-USZ
Biologically Active Natural Products Research Group, University of Szeged, Szeged H-6720, Hungary
| |
Collapse
|
12
|
Sullivan JR, Courtine C, Taylor L, Solomon O, Behr MA. Loss of allosteric regulation in α-isopropylmalate synthase identified as an antimicrobial resistance mechanism. NPJ ANTIMICROBIALS AND RESISTANCE 2023; 1:7. [PMID: 38686213 PMCID: PMC11057210 DOI: 10.1038/s44259-023-00005-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 04/18/2023] [Indexed: 05/02/2024]
Abstract
Despite our best efforts to discover new antimicrobials, bacteria have evolved mechanisms to become resistant. Resistance to antimicrobials can be attributed to innate, inducible, and acquired mechanisms. Mycobacterium abscessus is one of the most antimicrobial resistant bacteria and is known to cause chronic pulmonary infections within the cystic fibrosis community. Previously, we identified epetraborole as an inhibitor against M. abscessus with in vitro and in vivo activities and that the efficacy of epetraborole could be improved with the combination of the non-proteinogenic amino acid norvaline. Norvaline demonstrated activity against the M. abscessus epetraborole resistant mutants thus, limiting resistance to epetraborole in wild-type populations. Here we show M. abscessus mutants with resistance to epetraborole can acquire resistance to norvaline in a leucyl-tRNA synthetase (LeuRS) editing-independent manner. After showing that the membrane hydrophobicity and efflux activity are not linked to norvaline resistance, whole-genome sequencing identified a mutation in the allosteric regulatory domain of α-isopropylmalate synthase (α-IPMS). We found that mutants with the α-IPMSA555V variant incorporated less norvaline in the proteome and produced more leucine than the parental strain. Furthermore, we found that leucine can rescue growth inhibition from norvaline challenge in the parental strain. Our results demonstrate that M. abscessus can modulate its metabolism through mutations in an allosteric regulatory site to upregulate the biosynthesis of the natural LeuRS substrate and outcompete norvaline. These findings emphasize the antimicrobial resistant nature of M. abscessus and describe a unique mechanism of substrate-inhibitor competition.
Collapse
Affiliation(s)
- Jaryd R. Sullivan
- Infectious Diseases and Immunity in Global Health Program, Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1 Canada
- Department of Microbiology & Immunology, McGill University, Montreal, QC H3A 2B4 Canada
- McGill International TB Centre, Montreal, QC H4A 3S5 Canada
| | - Christophe Courtine
- Infectious Diseases and Immunity in Global Health Program, Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1 Canada
- Department of Microbiology & Immunology, McGill University, Montreal, QC H3A 2B4 Canada
- Present Address: Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth College, Hanover, NH 03755 USA
| | - Lorne Taylor
- Clinical Proteomics Platform, Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1 Canada
| | - Ori Solomon
- Infectious Diseases and Immunity in Global Health Program, Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1 Canada
- Department of Microbiology & Immunology, McGill University, Montreal, QC H3A 2B4 Canada
- McGill International TB Centre, Montreal, QC H4A 3S5 Canada
| | - Marcel A. Behr
- Infectious Diseases and Immunity in Global Health Program, Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1 Canada
- Department of Microbiology & Immunology, McGill University, Montreal, QC H3A 2B4 Canada
- McGill International TB Centre, Montreal, QC H4A 3S5 Canada
- Department of Medicine, McGill University Health Centre, Montreal, QC H3G 2M1 Canada
| |
Collapse
|
13
|
Tükenmez H, Singh P, Sarkar S, Çakır M, Oliveira AH, Lindgren C, Vaitkevicius K, Bonde M, Sauer-Eriksson AE, Almqvist F, Johansson J. A Highly Substituted Ring-Fused 2-Pyridone Compound Targeting PrfA and the Efflux Regulator BrtA in Listeria monocytogenes. mBio 2023; 14:e0044923. [PMID: 37120759 PMCID: PMC10294697 DOI: 10.1128/mbio.00449-23] [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: 02/21/2023] [Accepted: 03/20/2023] [Indexed: 05/01/2023] Open
Abstract
Listeria monocytogenes is a facultative Gram-positive bacterium that causes listeriosis, a severe foodborne disease. We previously discovered that ring-fused 2-pyridone compounds can decrease virulence factor expression in Listeria by binding and inactivating the PrfA virulence activator. In this study, we tested PS900, a highly substituted 2-pyridone that was recently discovered to be bactericidal to other Gram-positive pathogenic bacteria, such as Staphylococcus aureus and Enterococcus faecalis. We show that PS900 can interact with PrfA and reduce the expression of virulence factors. Unlike previous ring-fused 2-pyridones shown to inactivate PrfA, PS900 had an additional antibacterial activity and was found to potentiate sensitivity toward cholic acid. Two PS900-tolerant mutants able to grow in the presence of PS900 carried mutations in the brtA gene, encoding the BrtA repressor. In wild-type (WT) bacteria, cholic acid binds and inactivates BrtA, thereby alleviating the expression of the multidrug transporter MdrT. Interestingly, we found that PS900 also binds to BrtA and that this interaction causes BrtA to dissociate from its binding site in front of the mdrT gene. In addition, we observed that PS900 potentiated the effect of different osmolytes. We suggest that the increased potency of cholic acid and osmolytes to kill bacteria in the presence of PS900 is due to the ability of the latter to inhibit general efflux, through a yet-unknown mechanism. Our data indicate that thiazolino 2-pyridones constitute an attractive scaffold when designing new types of antibacterial agents. IMPORTANCE Bacteria resistant to one or several antibiotics are a very large problem, threatening not only treatment of infections but also surgery and cancer treatments. Thus, new types of antibacterial drugs are desperately needed. In this work, we show that a new generation of substituted ring-fused 2-pyridones not only inhibit Listeria monocytogenes virulence gene expression, presumably by inactivating the PrfA virulence regulator, but also potentiate the bactericidal effects of cholic acid and different osmolytes. We identified a multidrug repressor as a second target of 2-pyridones. The repressor-2-pyridone interaction displaces the repressor from DNA, thus increasing the expression of a multidrug transporter. In addition, our data suggest that the new class of ring-fused 2-pyridones are efficient efflux inhibitors, possibly explaining why the simultaneous addition of 2-pyridones together with cholic acid or osmolytes is detrimental for the bacterium. This work proves conclusively that 2-pyridones constitute a promising scaffold to build on for future antibacterial drug design.
Collapse
Affiliation(s)
- Hasan Tükenmez
- Department of Chemistry, Umeå University, Umeå, Sweden
- Umeå Centre of Microbial Research (UCMR), Umeå University, Umeå, Sweden
- Molecular Infection Medicine, Sweden (MIMS), Umeå University, Umeå, Sweden
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- QureTech Bio, Umeå, Sweden
| | - Pardeep Singh
- Department of Chemistry, Umeå University, Umeå, Sweden
| | - Souvik Sarkar
- Department of Chemistry, Umeå University, Umeå, Sweden
- Umeå Centre of Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Melike Çakır
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Ana H. Oliveira
- Umeå Centre of Microbial Research (UCMR), Umeå University, Umeå, Sweden
- Molecular Infection Medicine, Sweden (MIMS), Umeå University, Umeå, Sweden
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | | | - Karolis Vaitkevicius
- Umeå Centre of Microbial Research (UCMR), Umeå University, Umeå, Sweden
- Molecular Infection Medicine, Sweden (MIMS), Umeå University, Umeå, Sweden
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | | | - A. Elisabeth Sauer-Eriksson
- Department of Chemistry, Umeå University, Umeå, Sweden
- Umeå Centre of Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Fredrik Almqvist
- Department of Chemistry, Umeå University, Umeå, Sweden
- Umeå Centre of Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Jörgen Johansson
- Umeå Centre of Microbial Research (UCMR), Umeå University, Umeå, Sweden
- Molecular Infection Medicine, Sweden (MIMS), Umeå University, Umeå, Sweden
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| |
Collapse
|
14
|
Almeida MC, Szemerédi N, Durães F, Long S, Resende DISP, Martins da Costa P, Pinto M, Spengler G, Sousa E. Effect of Indole-Containing Pyrazino[2,1- b]quinazoline-3,6-diones in the Virulence of Resistant Bacteria. Antibiotics (Basel) 2023; 12:antibiotics12050922. [PMID: 37237825 DOI: 10.3390/antibiotics12050922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/12/2023] [Accepted: 05/15/2023] [Indexed: 05/28/2023] Open
Abstract
Drug resistance is rising to alarming levels, constituting one of the major threats to global health. The overexpression of efflux pumps and the formation of biofilms constitute two of the most common resistance mechanisms, favoring the virulence of bacteria. Therefore, the research and development of effective antimicrobial agents that can also counteract resistance mechanisms are extremely important. Pyrazino[2,1-b]quinazoline-3,6-diones, from marine and terrestrial organisms and simpler synthetic analogues, were recently disclosed by us as having relevant antimicrobial properties. In this study, using a multi-step approach, it was possible to synthesize new pyrazino[2,1-b]quinazoline-3,6-diones focusing on compounds with fluorine substituents since, to the best of our knowledge, the synthesis of fluorinated fumiquinazoline derivatives had not been attempted before. The new synthesized derivatives were screened for antibacterial activity and, along with previously synthetized pyrazino[2,1-b]quinazoline-3,6-diones, were characterized for their antibiofilm and efflux-pump-inhibiting effects against representative bacterial species and relevant resistant clinical strains. Several compounds showed relevant antibacterial activity against the tested Gram-positive bacterial species with MIC values in the range of 12.5-77 μM. Furthermore, some derivatives showed promising results as antibiofilm agents in a crystal violet assay. The results of the ethidium bromide accumulation assay suggested that some compounds could potentially inhibit bacterial efflux pumps.
Collapse
Affiliation(s)
- Mariana C Almeida
- Laboratório de Química Orgânica e Farmacêutica, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
- CIIMAR--Centro Interdisciplinar de Investigação Marinha e Ambiental, Terminal de Cruzeiros do Porto de Leixões, 4450-208 Matosinhos, Portugal
| | - Nikoletta Szemerédi
- Department of Medical Microbiology, Albert Szent-Gyorgyi Health Center and Albert Szent-Gyorgyi Medical School, University of Szeged, Semmelweis utca 6, 6725 Szeged, Hungary
| | - Fernando Durães
- Laboratório de Química Orgânica e Farmacêutica, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
- CIIMAR--Centro Interdisciplinar de Investigação Marinha e Ambiental, Terminal de Cruzeiros do Porto de Leixões, 4450-208 Matosinhos, Portugal
| | - Solida Long
- Laboratório de Química Orgânica e Farmacêutica, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
- Department of Bioengineering, Royal University of Phnom Penh, Russian Confederation Blvd, Phnom Penh 12156, Cambodia
| | - Diana I S P Resende
- Laboratório de Química Orgânica e Farmacêutica, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
- CIIMAR--Centro Interdisciplinar de Investigação Marinha e Ambiental, Terminal de Cruzeiros do Porto de Leixões, 4450-208 Matosinhos, Portugal
| | - Paulo Martins da Costa
- CIIMAR--Centro Interdisciplinar de Investigação Marinha e Ambiental, Terminal de Cruzeiros do Porto de Leixões, 4450-208 Matosinhos, Portugal
- ICBAS-Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
| | - Madalena Pinto
- Laboratório de Química Orgânica e Farmacêutica, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
- CIIMAR--Centro Interdisciplinar de Investigação Marinha e Ambiental, Terminal de Cruzeiros do Porto de Leixões, 4450-208 Matosinhos, Portugal
| | - Gabriella Spengler
- Department of Medical Microbiology, Albert Szent-Gyorgyi Health Center and Albert Szent-Gyorgyi Medical School, University of Szeged, Semmelweis utca 6, 6725 Szeged, Hungary
| | - Emília Sousa
- Laboratório de Química Orgânica e Farmacêutica, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
- CIIMAR--Centro Interdisciplinar de Investigação Marinha e Ambiental, Terminal de Cruzeiros do Porto de Leixões, 4450-208 Matosinhos, Portugal
| |
Collapse
|
15
|
Pan J, Zheng N, An Q, Li Y, Sun S, Zhang W, Song X. Effects of cadmium and copper mixtures on antibiotic resistance genes in rhizosphere soil. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 259:115008. [PMID: 37196522 DOI: 10.1016/j.ecoenv.2023.115008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 05/08/2023] [Accepted: 05/10/2023] [Indexed: 05/19/2023]
Abstract
The evolvement and development of antibiotic resistance in microorganisms may be influenced by metals; however, it is still unclear how cadmium (Cd) and copper (Cu) combined affect the distribution and presence of antibiotic-resistance genes (ARGs) in rhizosphere soil. The aims of this research were to (1) compare the distribution patterns of bacterial communities and ARGs in response to the effects of Cd and Cu both separately and combined; (2) explore the possible mechanisms underlying the variation in soil bacterial communities and ARGs in addition to the combined effects of Cd, Cu, and various environmental variables (nutrients, pH, etc.); and (3) provide a reference for assessing the risks of metals (Cd and Cu) and ARGs. The findings showed that the multidrug resistance genes acrA and acrB and the transposon gene intI-1 were present in high relative abundance in bacterial communities. Cadmium and Cu had a substantial interaction effect on the abundance of acrA, whereas Cu had a notable main effect on the abundance of intI-1. According to the network analysis, the strong links between bacterial taxa and specific ARGs revealed that most ARGs were hosted by Proteobacteria, Actinobacteria, and Bacteroidetes. According to structural equation modeling, Cd had a larger effect on ARGs than Cu. Compared to previous analyses of ARGs, bacterial community diversity had little effect on ARGs in this study. Overall, the results may have important consequences for determining the possible hazard of soil metals and extend the understanding of how Cd and Cu co-select ARGs in rhizosphere soils.
Collapse
Affiliation(s)
- Jiamin Pan
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Na Zheng
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China; Key Laboratory of Groundwater Resources and Environment of the Ministry of Education, College of New Energy and Environment, Jilin University 130021, China.
| | - Qirui An
- Key Laboratory of Groundwater Resources and Environment of the Ministry of Education, College of New Energy and Environment, Jilin University 130021, China
| | - Yunyang Li
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Siyu Sun
- Key Laboratory of Groundwater Resources and Environment of the Ministry of Education, College of New Energy and Environment, Jilin University 130021, China
| | - Wenhui Zhang
- Key Laboratory of Groundwater Resources and Environment of the Ministry of Education, College of New Energy and Environment, Jilin University 130021, China
| | - Xue Song
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
| |
Collapse
|
16
|
Sajid S, Salas LH, Rafiq M, Lund T, Jørgensen MG, Honoré B, Christensen LP, Hansen PR, Franzyk H, Mirza O, Prabhala BK. Physiological response in E. coli to YdgR overexpression depends on whether the protein has an intact function. Biochem Biophys Res Commun 2023; 661:42-49. [PMID: 37087797 DOI: 10.1016/j.bbrc.2023.04.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/13/2023] [Accepted: 04/14/2023] [Indexed: 04/25/2023]
Abstract
Membrane transport proteins are essential for the transport of a wide variety of molecules across the cell membrane to maintain cellular homeostasis. Generally, these transport proteins can be overexpressed in a suitable host (bacteria, yeast, or mammalian cells), and it is well documented that overexpression of membrane proteins alters the global metabolomic and proteomic profiles of the host cells. In the present study, we investigated the physiological consequences of overexpression of a membrane transport protein YdgR that belongs to the POT/PTR family from E. coli by using the lab strain BL21 (DE3)pLysS in its functional and attenuated mutant YdgR-E33Q. We found significant differences between the omics (metabolomics and proteomics) profiles of the cells expressing functional YdgR as compared to cells expressing attenuated YdgR, e.g., upregulation of several uncharacterized y-proteins and enzymes involved in the metabolism of peptides and amino acids. Furthermore, molecular network analysis suggested a relatively higher presence of proline-containing tripeptides in cells expressing functional YdgR. We envisage that an in-depth investigation of physiological alterations due to protein over-expression may be used for the deorphanization of the y-gene transportome.
Collapse
Affiliation(s)
- Salvia Sajid
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark; Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100, København Ø, Denmark
| | - Lilia Hernandez Salas
- Department of Science and Environment, Roskilde University, Universitetsvej 1, 10.1, DK-4000, Roskilde, Denmark
| | - Maria Rafiq
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100, København Ø, Denmark
| | - Torben Lund
- Department of Science and Environment, Roskilde University, Universitetsvej 1, 10.1, DK-4000, Roskilde, Denmark
| | - Mikkel Girke Jørgensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Bent Honoré
- Department of Biomedicine, Aarhus University, Nordre Ringgade 1, 8000, Aarhus C, Denmark
| | - Lars Porskjær Christensen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Paul Robert Hansen
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100, København Ø, Denmark
| | - Henrik Franzyk
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100, København Ø, Denmark
| | - Osman Mirza
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100, København Ø, Denmark
| | - Bala Krishna Prabhala
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark.
| |
Collapse
|
17
|
Abu Lila AS, Alharby TN, Alanazi J, Alanazi M, Abdallah MH, Rizvi SMD, Moin A, Khafagy ES, Tabrez S, Al Balushi AA, Hegazy WAH. Clinical Resistant Strains of Enterococci and Their Correlation to Reduced Susceptibility to Biocides: Phenotypic and Genotypic Analysis of Macrolides, Lincosamides, and Streptogramins. Antibiotics (Basel) 2023; 12:antibiotics12030461. [PMID: 36978327 PMCID: PMC10044631 DOI: 10.3390/antibiotics12030461] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 02/20/2023] [Accepted: 02/22/2023] [Indexed: 03/03/2023] Open
Abstract
Enterococci are troublesome nosocomial, opportunistic Gram-positive cocci bacteria showing enhanced resistance to many commonly used antibiotics. This study aims to investigate the prevalence and genetic basis of antibiotic resistance to macrolides, lincosamides, and streptogramins (MLS) in Enterococci, as well as the correlation between MLS resistance and biocide resistance. From 913 clinical isolates collected from King Khalid Hospital, Hail, Saudi Arabia, 131 isolates were identified as Enterococci spp. The susceptibility of the clinical enterococcal isolates to several MLS antibiotics was determined, and the resistance phenotype was detected by the triple disk method. The MLS-involved resistance genes were screened in the resistant isolates. The current results showed high resistance rates to MLS antibiotics, and the constitutive resistance to all MLS (cMLS) was the most prevalent phenotype, observed in 76.8% of resistant isolates. By screening the MLS resistance-encoding genes in the resistant isolates, the erythromycin ribosome methylase (erm) genes that are responsible for methylation of bacterial 23S rRNA were the most detected genes, in particular, ermB. The ereA esterase-encoding gene was the most detected MLS modifying-encoding genes, more than lnuA (adenylation) and mphC (phosphorylation). The minimum inhibitory concentrations (MICs) of commonly used biocides were detected in resistant isolates and correlated with the MICs of MLS antibiotics. The present findings showed a significant correlation between MLS resistance and reduced susceptibility to biocides. In compliance with the high incidence of the efflux-encoding genes, especially mefA and mefE genes in the tolerant isolates with higher MICs to both MLS antibiotics and biocides, the efflux of resistant isolates was quantified, and there was a significant increase in the efflux of resistant isolates with higher MICs as compared to those with lower MICs. This could explain the crucial role of efflux in developing cross-resistance to both MLS antibiotics and biocides.
Collapse
Affiliation(s)
- Amr Selim Abu Lila
- Department of Pharmaceutics, College of Pharmacy, University of Ha’il, Ha’il 81442, Saudi Arabia
- Molecular Diagnostics and Personalized Therapeutics Unit, University of Ha’il, Ha’il 81442, Saudi Arabia
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
- Correspondence: (A.S.A.L.); (W.A.H.H.)
| | - Tareq Nafea Alharby
- Department of Clinical Pharmacy, College of Pharmacy, University of Ha’il, Ha’il 81442, Saudi Arabia
| | - Jowaher Alanazi
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Ha’il, Ha’il 81442, Saudi Arabia
| | - Muteb Alanazi
- Department of Clinical Pharmacy, College of Pharmacy, University of Ha’il, Ha’il 81442, Saudi Arabia
| | - Marwa H. Abdallah
- Department of Pharmaceutics, College of Pharmacy, University of Ha’il, Ha’il 81442, Saudi Arabia
- Molecular Diagnostics and Personalized Therapeutics Unit, University of Ha’il, Ha’il 81442, Saudi Arabia
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
| | - Syed Mohd Danish Rizvi
- Department of Pharmaceutics, College of Pharmacy, University of Ha’il, Ha’il 81442, Saudi Arabia
- Molecular Diagnostics and Personalized Therapeutics Unit, University of Ha’il, Ha’il 81442, Saudi Arabia
| | - Afrasim Moin
- Department of Pharmaceutics, College of Pharmacy, University of Ha’il, Ha’il 81442, Saudi Arabia
- Molecular Diagnostics and Personalized Therapeutics Unit, University of Ha’il, Ha’il 81442, Saudi Arabia
| | - El-Sayed Khafagy
- Department of Pharmaceutics, College of Pharmacy, Prince Sattam bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt
| | - Shams Tabrez
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Abdullah Ali Al Balushi
- Pharmacy Program, Department of Pharmaceutics, Oman College of Health Sciences, Muscat 113, Oman
| | - Wael A. H. Hegazy
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
- Pharmacy Program, Department of Pharmaceutical Sciences, Oman College of Health Sciences, Muscat 113, Oman
- Correspondence: (A.S.A.L.); (W.A.H.H.)
| |
Collapse
|
18
|
Gains AF, Lambert DW, Stafford GP. Identification of a Czc-like operon of the periodontal pathobiont P. gingivalis involved in metal ion efflux. Anaerobe 2023; 80:102696. [PMID: 36642290 DOI: 10.1016/j.anaerobe.2023.102696] [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: 10/18/2022] [Revised: 01/06/2023] [Accepted: 01/09/2023] [Indexed: 01/15/2023]
Abstract
OBJECTIVE The study aimed to investigate the role of the PGN2012 gene of the periodontitis contributing pathobiont Porphyromonas gingivalis. PGN2012 is a homolgue of TolC and is a gene our group previously showed was overexpressed in hyperinvasive cells. METHODS The study used a combination of bioinformatics, knockout mutagenesis, growth experiments, biofilm assays and human cell invation assays to investigate PGN2012 function. RESULTS Bioinformatics identified that PGN2012 is part of one of four TolC containing gene loci in P. gingivalis that we predicted may encode a metal resistance RND family tripartite pump, similar to those present in other Gram-negative bacteria, but which are not well understood in anaerobic bacteria. A ΔPGN2012 deletion displayed slightly reduced growth in liquid culture but did not effect biofilm formation or human cell invasion. When metal ions were included in the medium the mutant displayed significantly increased sensitivity to the divalent metal ions Zn2+ (500 μM), Co2+ (2 mM), and Cd2+(0.1 mM) but not Cu2+. CONCLUSIONS We propose to rename the PGN2012-2014 genes czcCBA, which we suggest plays a role in intracellular stress resistance where zinc is often employed by host cells in antibacterial defence with implications for chronic infection in humans.
Collapse
Affiliation(s)
- A F Gains
- School of Clinical Dentistry, University of Sheffield, Sheffield, S10 2TA, UK
| | - D W Lambert
- School of Clinical Dentistry, University of Sheffield, Sheffield, S10 2TA, UK
| | - G P Stafford
- School of Clinical Dentistry, University of Sheffield, Sheffield, S10 2TA, UK.
| |
Collapse
|
19
|
Fernández-Fernández R, Olivenza DR, Sánchez-Romero MA. Identifying Bacterial Lineages in Salmonella by Flow Cytometry. EcoSal Plus 2022; 10:eESP00182021. [PMID: 35148202 PMCID: PMC10729938 DOI: 10.1128/ecosalplus.esp-0018-2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 12/21/2021] [Indexed: 12/16/2022]
Abstract
Advances in technologies that permit high-resolution analysis of events in single cells have revealed that phenotypic heterogeneity is a widespread phenomenon in bacteria. Flow cytometry has the potential to describe the distribution of cellular properties within a population of bacterial cells and has yielded invaluable information about the ability of isogenic cells to diversify into phenotypic subpopulations. This review will discuss several single-cell approaches that have recently been applied to define phenotypic heterogeneity in populations of Salmonella enterica.
Collapse
Affiliation(s)
| | - David R. Olivenza
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | | |
Collapse
|
20
|
Barnabas V, Kashyap A, Raja R, Newar K, Rai D, Dixit NM, Mehra S. The Extent of Antimicrobial Resistance Due to Efflux Pump Regulation. ACS Infect Dis 2022; 8:2374-2388. [PMID: 36264222 DOI: 10.1021/acsinfecdis.2c00460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A key mechanism driving antimicrobial resistance (AMR) stems from the ability of bacteria to up-regulate efflux pumps upon exposure to drugs. The resistance gained by this up-regulation is pliable because of the tight regulation of efflux pump levels. This leads to temporary enhancement in survivability of bacteria due to higher efflux pump levels in the presence of antibiotics, which can be reversed when the cells are no longer exposed to the drug. Knowledge of the extent of resistance thus gained would inform intervention strategies aimed at mitigating AMR. Here, we combine mathematical modeling and experiments to quantify the maximum extent of resistance that efflux pump up-regulation can confer via phenotypic induction in the presence of drugs and genotypic abrogation of regulation. Our model describes the dynamics of drug transport in and out of cells coupled with the associated regulation of efflux pump levels and predicts the increase in the minimum inhibitory concentration (MIC) of drugs due to such regulation. To test the model, we measured the uptake and efflux as well as the MIC of the compound ethidium bromide (EtBr), a substrate of the efflux pump LfrA, in wild-type Mycobacterium smegmatis mc2155, as well as in two laboratory-generated strains. Our model captured the observed EtBr levels and MIC fold-changes quantitatively. Further, the model identified key parameters associated with the resulting resistance, variations in which could underlie the extent to which such resistance arises across different drug-bacteria combinations, potentially offering tunable handles to optimize interventions aimed at minimizing AMR.
Collapse
Affiliation(s)
- Vinay Barnabas
- Department of Chemical Engineering, Indian Institute of Technology, Mumbai400076, India
| | - Akanksha Kashyap
- Department of Chemical Engineering, Indian Institute of Technology, Mumbai400076, India
| | - Rubesh Raja
- Department of Chemical Engineering, Indian Institute of Science, Bangalore560012, India
| | - Kapil Newar
- Department of Chemical Engineering, Indian Institute of Science, Bangalore560012, India
| | - Deepika Rai
- Department of Chemical Engineering, Indian Institute of Technology, Mumbai400076, India
| | - Narendra M Dixit
- Department of Chemical Engineering, Indian Institute of Science, Bangalore560012, India.,Centre for Biosystems Science and Engineering, Indian Institute of Science, Bangalore560012, India
| | - Sarika Mehra
- Department of Chemical Engineering, Indian Institute of Technology, Mumbai400076, India
| |
Collapse
|
21
|
Nye TM, Tükenmez H, Singh P, Flores-Mireles AL, Obernuefemann CLP, Pinkner JS, Sarkar S, Bonde M, Lindgren AEG, Dodson KW, Johansson J, Almqvist F, Caparon MG, Hultgren SJ. Ring-fused 2-pyridones effective against multidrug-resistant Gram-positive pathogens and synergistic with standard-of-care antibiotics. Proc Natl Acad Sci U S A 2022; 119:e2210912119. [PMID: 36252016 PMCID: PMC9618150 DOI: 10.1073/pnas.2210912119] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 09/27/2022] [Indexed: 01/21/2023] Open
Abstract
The alarming rise of multidrug-resistant Gram-positive bacteria has precipitated a healthcare crisis, necessitating the development of new antimicrobial therapies. Here we describe a new class of antibiotics based on a ring-fused 2-pyridone backbone, which are active against vancomycin-resistant enterococci (VRE), a serious threat as classified by the Centers for Disease Control and Prevention, and other multidrug-resistant Gram-positive bacteria. Ring-fused 2-pyridone antibiotics have bacteriostatic activity against actively dividing exponential phase enterococcal cells and bactericidal activity against nondividing stationary phase enterococcal cells. The molecular mechanism of drug-induced killing of stationary phase cells mimics aspects of fratricide observed in enterococcal biofilms, where both are mediated by the Atn autolysin and the GelE protease. In addition, combinations of sublethal concentrations of ring-fused 2-pyridones and standard-of-care antibiotics, such as vancomycin, were found to synergize to kill clinical strains of VRE. Furthermore, a broad range of antibiotic resistant Gram-positive pathogens, including those responsible for the increasing incidence of antibiotic resistant healthcare-associated infections, are susceptible to this new class of 2-pyridone antibiotics. Given the broad antibacterial activities of ring-fused 2-pyridone compounds against Gram-positive (GmP) bacteria we term these compounds GmPcides, which hold promise in combating the rising tide of antibiotic resistant Gram-positive pathogens.
Collapse
Affiliation(s)
- Taylor M. Nye
- Department of Molecular Microbiology and Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, MO 63110-1093
| | - Hasan Tükenmez
- Department of Chemistry, Umeå University, SE-90187 Umeå, Sweden
- Department of Molecular Biology, Umeå University, SE-90187 Umeå, Sweden
- Umeå Centre for Microbial Research, UCMR, Umeå University, SE-90187 Umeå, Sweden
| | - Pardeep Singh
- Department of Chemistry, Umeå University, SE-90187 Umeå, Sweden
- Umeå Centre for Microbial Research, UCMR, Umeå University, SE-90187 Umeå, Sweden
| | | | - Chloe L. P. Obernuefemann
- Department of Molecular Microbiology and Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, MO 63110-1093
| | - Jerome S. Pinkner
- Department of Molecular Microbiology and Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, MO 63110-1093
| | - Souvik Sarkar
- Department of Chemistry, Umeå University, SE-90187 Umeå, Sweden
- Umeå Centre for Microbial Research, UCMR, Umeå University, SE-90187 Umeå, Sweden
| | - Mari Bonde
- Department of Chemistry, Umeå University, SE-90187 Umeå, Sweden
- QureTech Bio, Umeå, Sweden
| | - Anders E. G. Lindgren
- Department of Chemistry, Umeå University, SE-90187 Umeå, Sweden
- Umeå Centre for Microbial Research, UCMR, Umeå University, SE-90187 Umeå, Sweden
| | - Karen W. Dodson
- Department of Molecular Microbiology and Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, MO 63110-1093
| | - Jörgen Johansson
- Department of Molecular Biology, Umeå University, SE-90187 Umeå, Sweden
- Umeå Centre for Microbial Research, UCMR, Umeå University, SE-90187 Umeå, Sweden
| | - Fredrik Almqvist
- Department of Chemistry, Umeå University, SE-90187 Umeå, Sweden
- Umeå Centre for Microbial Research, UCMR, Umeå University, SE-90187 Umeå, Sweden
| | - Michael G. Caparon
- Department of Molecular Microbiology and Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, MO 63110-1093
| | - Scott J. Hultgren
- Department of Molecular Microbiology and Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, MO 63110-1093
| |
Collapse
|
22
|
Gupta A, Bernacchia L, Kad N. Culture media, DMSO and efflux affect the antibacterial activity of cisplatin and oxaliplatin. Lett Appl Microbiol 2022; 75:951-956. [PMID: 35699349 PMCID: PMC9796146 DOI: 10.1111/lam.13767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/19/2022] [Accepted: 05/20/2022] [Indexed: 01/01/2023]
Abstract
Cisplatin was originally discovered through its antibacterial action and subsequently has found use as a potent broad-spectrum anticancer agent. This study determines the effect of growth media and solvent on the antibacterial activity of cisplatin and its analogue, oxaliplatin. Escherichia coli MG1655 or MG1655 ΔtolC was treated with the platinum compounds under different conditions and susceptibility was determined. Our results showed that DMSO reduced the activity of cisplatin by fourfold (MIC 12·5 mg l-1 ) compared with 0·9% NaCl-solubilized cisplatin (MIC 3·12 mg l-1 ) when tested in MOPS. Surprisingly, complete loss of activity was observed in Mueller-Hinton Broth II (MHB II). By supplementing MOPS with individual components of MHB II such as the sulphur-containing amino acids, l-cysteine and l-methionine, individually or in combination reduced activity by ≥8-fold (MIC ≥25 mg l-1 ). Oxaliplatin was less active against E. coli (MIC 100 mg l-1 ) but exhibited similar inactivation in the presence of DMSO, MHBII or MOPS spiked with l-cysteine and l-methionine (MIC ≥400 mg l-1 ). Our data suggest that the antibacterial activity of cisplatin and oxaliplatin is modulated by both choice of solvent and composition of growth media. We demonstrate that this is primarily due to sulphur-containing amino acids cysteine and methionine, an essential component of the recommended media for testing antimicrobial susceptibility, MHBII.
Collapse
Affiliation(s)
- A. Gupta
- School of Biological Sciences, Division of Natural SciencesUniversity of KentCanterburyUK
| | - L. Bernacchia
- School of Biological Sciences, Division of Natural SciencesUniversity of KentCanterburyUK
| | - N.M. Kad
- School of Biological Sciences, Division of Natural SciencesUniversity of KentCanterburyUK
| |
Collapse
|
23
|
Phytolectin-cationic lipid complex revive ciprofloxacin efficacy against multi-drug resistant uropathogenic Escherichia coli. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.128970] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
24
|
Abdel-Karim SAAM, El-Ganiny AMA, El-Sayed MA, Abbas HAA. Promising FDA-approved drugs with efflux pump inhibitory activities against clinical isolates of Staphylococcus aureus. PLoS One 2022; 17:e0272417. [PMID: 35905077 PMCID: PMC9337675 DOI: 10.1371/journal.pone.0272417] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 07/19/2022] [Indexed: 12/04/2022] Open
Abstract
Background and objectives Staphylococcus aureus is an opportunistic pathogen that causes wide range of nosocomial and community-acquired infections which have spread worldwide leading to an urgent need for developing effective anti-staphylococcal agents. Efflux is an important resistance mechanism that bacteria used to fight the antimicrobial action. This study aimed to investigate the efflux mechanism in S. aureus and assess diclofenac, domperidone, glyceryl trinitrate and metformin as potential efflux pump inhibitors that can be used in combination with antibiotics for treating topical infections caused by S. aureus. Materials and methods Efflux was detected qualitatively by the ethidium bromide Cart-Wheel method followed by investigating the presence of efflux genes by polymerase chain reaction. Twenty-six isolates were selected for further investigation of efflux by Cart-Wheel method in absence and presence of tested compounds followed by quantitative efflux assay. Furthermore, antibiotics minimum inhibitory concentrations in absence and presence of tested compounds were determined. The effects of tested drugs on expression levels of efflux genes norA, fexA and tetK were determined by quantitative real time-polymerase chain reaction. Results Efflux was found in 65.3% of isolates, the prevalence of norA, tetK, fexA and msrA genes were 91.7%, 77.8%, 27.8% and 6.9%. Efflux assay revealed that tested drugs had potential efflux inhibitory activities, reduced the antibiotic’s MICs and significantly decreased the relative expression of efflux genes. Conclusion Diclofenac sodium, domperidone and glyceryl trinitrate showed higher efflux inhibitory activities than verapamil and metformin. To our knowledge, this is the first report that shows that diclofenac sodium, glyceryl trinitrate and domperidone have efflux pump inhibitory activities against S. aureus.
Collapse
Affiliation(s)
| | | | - Mona Abdelmonem El-Sayed
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | | |
Collapse
|
25
|
Brar A, Majumder S, Navarro MZ, Benoit-Biancamano MO, Ronholm J, George S. Nanoparticle-Enabled Combination Therapy Showed Superior Activity against Multi-Drug Resistant Bacterial Pathogens in Comparison to Free Drugs. NANOMATERIALS 2022; 12:nano12132179. [PMID: 35808015 PMCID: PMC9268018 DOI: 10.3390/nano12132179] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 06/14/2022] [Accepted: 06/22/2022] [Indexed: 02/04/2023]
Abstract
The emergence of multidrug-resistant (MDR) bacterial pathogens in farm animals and their zoonotic spread is a concern to both animal agriculture and public health. Apart from antimicrobial resistance (AMR), bacterial pathogens from the genera of Salmonella and Staphylococcus take refuge inside host cells, thereby demanding intervention strategies that can eliminate intracellular MDR pathogens. In this study, seven clinical isolates of Salmonella and Staphylococcus from swine farms were characterized for antibiotic (n = 24) resistance, resistance mechanisms, and virulence characteristics. All isolates showed resistance to one or more antibiotics and S. enterica ser. Typhimurium isolate had the highest resistance to the panel of antibiotics tested. Major resistance mechanisms identified were efflux pump and beta-lactamase enzyme activities. Staphylococcus isolates showed complete hemolysis and strong biofilm formation, while Salmonella isolates caused partial hemolysis, but showed no or weak biofilm formation. MDR isolates of S. aureus M12 and S. enterica ser. Typhimurium bacteria were subsequently tested against combinations of antibiotics and potentiating adjuvants for improved antibacterial efficacy using a checkerboard assay, and their fractional inhibitory concentration index (FICI) was calculated. A combination of chitosan and silica nanoparticles containing tetracycline (TET) and efflux pump inhibitor chlorpromazine (CPZ), respectively, was characterized for physicochemical properties and effectiveness against MDR Salmonella enterica ser. Typhimurium isolate. This combination of nano-encapsulated drugs improved the antibacterial efficacy by inhibiting AMR mechanisms (efflux activity, beta-lactamase enzyme activity, and hydrogen sulfide (H2S) production) and reducing intracellular pathogen load by 83.02 ± 14.35%. In conclusion, this study sheds light on the promising applicability of nanoparticle-enabled combination therapy to combat multidrug-resistant pathogens encountered in animal agriculture.
Collapse
Affiliation(s)
- Amarpreet Brar
- Department of Food Science and Agricultural Chemistry, Macdonald Campus, McGill University, 21111 Lakeshore, Ste Anne de Bellevue, QC H9X 3V9, Canada; (A.B.); (S.M.); (J.R.)
- Swine and Poultry Infectious Diseases Research Center (CRIPA), Faculté de Médecine Vétérinaire, Université de Montréal, 3200 Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada; (M.Z.N.); (M.-O.B.-B.)
| | - Satwik Majumder
- Department of Food Science and Agricultural Chemistry, Macdonald Campus, McGill University, 21111 Lakeshore, Ste Anne de Bellevue, QC H9X 3V9, Canada; (A.B.); (S.M.); (J.R.)
- Swine and Poultry Infectious Diseases Research Center (CRIPA), Faculté de Médecine Vétérinaire, Université de Montréal, 3200 Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada; (M.Z.N.); (M.-O.B.-B.)
| | - Maria Zardon Navarro
- Swine and Poultry Infectious Diseases Research Center (CRIPA), Faculté de Médecine Vétérinaire, Université de Montréal, 3200 Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada; (M.Z.N.); (M.-O.B.-B.)
- Research Group on Infectious Diseases in Production Animals (GREMIP), Department of Pathology and Microbiology, Faculté de Médecine Vétérinaire, Université de Montréal, 3200 Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada
| | - Marie-Odile Benoit-Biancamano
- Swine and Poultry Infectious Diseases Research Center (CRIPA), Faculté de Médecine Vétérinaire, Université de Montréal, 3200 Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada; (M.Z.N.); (M.-O.B.-B.)
- Research Group on Infectious Diseases in Production Animals (GREMIP), Department of Pathology and Microbiology, Faculté de Médecine Vétérinaire, Université de Montréal, 3200 Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada
| | - Jennifer Ronholm
- Department of Food Science and Agricultural Chemistry, Macdonald Campus, McGill University, 21111 Lakeshore, Ste Anne de Bellevue, QC H9X 3V9, Canada; (A.B.); (S.M.); (J.R.)
- Department of Animal Science, Macdonald Campus, McGill University, 2111 Lakeshore, Ste Anne de Bellevue, QC H9X 3V9, Canada
| | - Saji George
- Department of Food Science and Agricultural Chemistry, Macdonald Campus, McGill University, 21111 Lakeshore, Ste Anne de Bellevue, QC H9X 3V9, Canada; (A.B.); (S.M.); (J.R.)
- Swine and Poultry Infectious Diseases Research Center (CRIPA), Faculté de Médecine Vétérinaire, Université de Montréal, 3200 Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada; (M.Z.N.); (M.-O.B.-B.)
- Correspondence: ; Tel.: +1-514-398-7920; Fax: +1-514-398-7990
| |
Collapse
|
26
|
Functional Role of YnfA, an Efflux Transporter in Resistance to Antimicrobial Agents in Shigella flexneri. Antimicrob Agents Chemother 2022; 66:e0029322. [PMID: 35727058 PMCID: PMC9295541 DOI: 10.1128/aac.00293-22] [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
Shigella flexneri has become a significant public health concern accounting for the majority of shigellosis cases worldwide. Even though a multitude of efforts is being made into the development of a vaccine to prevent infections, the absence of a licensed global vaccine compels us to enormously depend on antibiotics as the major treatment option. The extensive-unregulated use of antibiotics for treatment along with natural selection in bacteria has led to the rising of multidrug-resistance Shigella strains. Out of the various mechanisms employed by bacteria to gain resistance, efflux transporters are considered to be one of the principal contributors to antimicrobial resistance. The small multidrug-resistance family consists of unique small proteins that act as efflux pumps and are involved in extruding various antimicrobial compounds. The present study aims to demonstrate the role of an efflux transporter YnfA belonging to the SMR family and its functional involvement in promoting antimicrobial resistance in S. flexneri. Employing various genetic, computational, and biochemical techniques, we show how disrupting the YnfA transporter, renders the mutant Shigella strain more susceptible to some antimicrobial compounds tested in this study, and significantly affects the overall transport activity of the bacteria against ethidium bromide and acriflavine when compared with the wild-type Shigella strain. We also assessed how mutating some of the conserved amino acid residues of YnfA alters the resistance profile and efflux activity of the mutant YnfA transporter. This study provides a functional understanding of an uncharacterized SMR transporter YnfA of Shigella.
Collapse
|
27
|
Li W, Hadjigol S, Mazo AR, Holden J, Lenzo J, Shirbin SJ, Barlow A, Shabani S, Huang T, Reynolds EC, Qiao GG, O'Brien-Simpson NM. Star-Peptide Polymers are Multi-Drug-Resistant Gram-Positive Bacteria Killers. ACS APPLIED MATERIALS & INTERFACES 2022; 14:25025-25041. [PMID: 35500245 DOI: 10.1021/acsami.1c23734] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Antibiotic resistance in bacteria, especially Gram-positive bacteria like Staphylococcus aureus, is gaining considerable momentum worldwide and unless checked will pose a global health crisis. With few new antibiotics coming on the market, there is a need for novel antimicrobial materials that target and kill multi-drug-resistant (MDR) Gram-positive pathogens like methicillin-resistant Staphylococcus aureus (MRSA). In this study, using a novel mixed-bacteria antimicrobial assay, we show that the star-peptide polymers preferentially target and kill Gram-positive pathogens including MRSA. A major effect on the activity of the star-peptide polymer was structure, with an eight-armed structure inducing the greatest bactericidal activity. The different star-peptide polymer structures were found to induce different mechanisms of bacterial death both in vitro and in vivo. These results highlight the potential utility of peptide/polymers to fabricate materials for therapeutic development against MDR Gram-positive bacterial infections.
Collapse
Affiliation(s)
- Wenyi Li
- ACTV Research Group, Melbourne Dental School, Centre for Oral Health Research, Royal Dental Hospital and The Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Sara Hadjigol
- ACTV Research Group, Melbourne Dental School, Centre for Oral Health Research, Royal Dental Hospital and The Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Alicia Rasines Mazo
- Polymer Science Group, Department of Chemical & Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - James Holden
- Melbourne Dental School, Centre for Oral Health Research, Royal Dental Hospital and The Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Jason Lenzo
- Melbourne Dental School, Centre for Oral Health Research, Royal Dental Hospital and The Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Steven J Shirbin
- Polymer Science Group, Department of Chemical & Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Anders Barlow
- Materials Characterisation and Fabrication Platform, Melbourne School of Engineering, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Sadegh Shabani
- Polymer Science Group, Department of Chemical & Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Tao Huang
- Department of Biomedical Engineering, Melbourne School of Engineering, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Eric C Reynolds
- Melbourne Dental School, Centre for Oral Health Research, Royal Dental Hospital and The Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Greg G Qiao
- Polymer Science Group, Department of Chemical & Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Neil M O'Brien-Simpson
- ACTV Research Group, Melbourne Dental School, Centre for Oral Health Research, Royal Dental Hospital and The Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Parkville, Victoria 3010, Australia
| |
Collapse
|
28
|
Li Y, Wen H, Ge X. Opposite motion of the Central Helices of efflux pump KmrA is important for its export efficiency. Microb Pathog 2022; 167:105570. [PMID: 35550844 DOI: 10.1016/j.micpath.2022.105570] [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: 11/08/2021] [Revised: 04/11/2022] [Accepted: 05/05/2022] [Indexed: 10/18/2022]
Abstract
Efflux pump of Major Facilitator Superfamily (MFS) is widely distributed in bacteria, while its role in regulating antibiotic resistance of nosocomial pathogen Klebsiella pneumoniae remains unclear. Herein we analyzed the effect of amino acid substitution of MFS efflux pump KmrA on its export efficiency via molecular biology and molecular dynamics (MD). After searching across the 804 sequenced K. pneumoniae isolates, we identified four major variants of KmrA, while one of them KmrA-A was demonstrated an inactive one in MIC and ethidium bromide efflux assays. Subsequently, MD simulations of KmrA and its variants were conducted and the opposite motion of the central helices were observed for the active variants, while it was not found for KmrA-A. To further identify the importance of the opposite motion to the conformational transition, we calculated their differences in volume of binding pocket, salt bridge and hydrophilic interaction with water based on the rocker-switch model. Our results indicated that the opposite motion of KmrA conferred a larger binding pocket and stronger hydrogen bond with water at inward-facing conformation. An unusual substitution S374A of KmrA-A disrupted the normal motion of central helices by enhancing hydrophobic interactions between them, resulting into the altered positions and strengths of salt bridge, which was deduced to affect the conformational transition. Overall our data provided detailed information on the regular of KmrA's moving trajectory, demonstrating the importance of opposite motion of central helices to KmrA's export efficiency.
Collapse
Affiliation(s)
- Ying Li
- College of Biochemical Engineering, Beijing Union University, Beijing, 100023, China
| | - Honglin Wen
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, 100010, China
| | - Xizhen Ge
- College of Biochemical Engineering, Beijing Union University, Beijing, 100023, China.
| |
Collapse
|
29
|
Yi K, Liu S, Liu P, Luo X, Zhao J, Yan F, Pan Y, Liu J, Zhai Y, Hu G. Synergistic antibacterial activity of tetrandrine combined with colistin against MCR-mediated colistin-resistant Salmonella. Biomed Pharmacother 2022; 149:112873. [PMID: 35349932 DOI: 10.1016/j.biopha.2022.112873] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/21/2022] [Accepted: 03/23/2022] [Indexed: 11/15/2022] Open
Abstract
It has been recognized that colistin resistance is a growing problem that seriously impairs the clinical efficacy of colistin against bacterial infections. One strategy that has been proven to have therapeutic effect is to overcome the widespread emergence of antibiotic-resistant pathogens by combining existing antibiotics with promising non-antibiotic agents. In this work, antibiotic susceptibility testing, checkerboard assays and time-kill curves were used to investigate the antibacterial activity of the individual drugs and the potential synergistic activity of the combination. The molecular mechanisms of tetrandrine in combination with colistin were analyzed using fluorometric assay and Real-time PCR. To predict possible interactions between tetrandrine and MCR-1, molecular docking assay was taken. Finally, we evaluated the in vivo efficacy of tetrandrine in combination with colistin against MCR-positive Salmonella. Overall, the combination of tetrandrine and colistin showed significant synergistic activity. In-depth mechanistic analysis showed that the combination of tetrandrine with colistin enhances the membrane-damaging ability of colistin, undermines the functions of proton motive force (PMF) and efflux pumps in MCR-positive bacteria. The results of molecular docking and RT-PCR analyses showed that tetrandrine not only affects the expression of mcr-1 but is also an effective MCR-1 inhibitor. Compared with colistin monotherapy, the combination of tetrandrine with colistin significantly reduced the bacterial load in vivo. Our findings demonstrated that tetrandrine serves as a potential colistin adjuvant against MCR-positive Salmonella.
Collapse
Affiliation(s)
- Kaifang Yi
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
| | - Shuobo Liu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
| | - Peiyi Liu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
| | - Xingwei Luo
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
| | - Jinfeng Zhao
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
| | - Fengbin Yan
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
| | - Yushan Pan
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
| | - Jianhua Liu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
| | - Yajun Zhai
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, China.
| | - Gongzheng Hu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, China.
| |
Collapse
|
30
|
Phenolic Compound Ethyl 3,4-Dihydroxybenzoate Retards Drug Efflux and Potentiates Antibiotic Activity. Antibiotics (Basel) 2022; 11:antibiotics11040497. [PMID: 35453250 PMCID: PMC9029221 DOI: 10.3390/antibiotics11040497] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/04/2022] [Accepted: 04/06/2022] [Indexed: 12/04/2022] Open
Abstract
The World Health Organization indicated that antibiotic resistance is one of the greatest threats to health, food security, and development in the world. Drug resistance efflux pumps are essential for antibiotic resistance in bacteria. Here, we evaluated the plant phenolic compound ethyl 3,4-dihydroxybenzoate (EDHB) for its efflux pump inhibitory (EPI) activity against drug-resistant Escherichia coli. The half-maximal inhibitory concentration, modulation assays, and time-kill studies indicated that EDHB has limited antibacterial activity but can potentiate the activity of antibiotics for drug-resistant E. coli. Dye accumulation/efflux and MALDI-TOF studies showed that EDHB not only significantly increases dye accumulation and reduces dye efflux but also increases the extracellular amount of antibiotics in the drug-resistant E. coli, indicating its interference with substrate translocation via a bacterial efflux pump. Molecular docking analysis using AutoDock Vina indicated that EDHB putatively posed within the distal binding pocket of AcrB and in close interaction with the residues by H-bonds and hydrophobic contacts. Additionally, EDHB showed an elevated postantibiotic effect on drug-resistant E. coli. Our toxicity assays showed that EDHB did not change the bacterial membrane permeability and exhibited mild human cell toxicity. In summary, these findings indicate that EDHB could serve as a potential EPI for drug-resistant E. coli.
Collapse
|
31
|
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] [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
|
32
|
Anti-proliferative and antibacterial activity of oleo-gum-resin of Boswellia serrata extract and its isolate 3-hydroxy-11-keto-β-boswellic acid. J Herb Med 2022. [DOI: 10.1016/j.hermed.2022.100546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
33
|
Kerr R, Jabbari S, Blair JMA, Johnston IG. Dynamic Boolean modelling reveals the influence of energy supply on bacterial efflux pump expression. J R Soc Interface 2022; 19:20210771. [PMID: 35078338 PMCID: PMC8790346 DOI: 10.1098/rsif.2021.0771] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Antimicrobial resistance (AMR) is a global health issue. One key factor contributing to AMR is the ability of bacteria to export drugs through efflux pumps, which relies on the ATP-dependent expression and interaction of several controlling genes. Recent studies have shown that significant cell-to-cell ATP variability exists within clonal bacterial populations, but the contribution of intrinsic cell-to-cell ATP heterogeneity is generally overlooked in understanding efflux pumps. Here, we consider how ATP variability influences gene regulatory networks controlling expression of efflux pump genes in two bacterial species. We develop and apply a generalizable Boolean modelling framework, developed to incorporate the dependence of gene expression dynamics on available cellular energy supply. Theoretical results show that differences in energy availability can cause pronounced downstream heterogeneity in efflux gene expression. Cells with higher energy availability have a superior response to stressors. Furthermore, in the absence of stress, model bacteria develop heterogeneous pulses of efflux pump gene expression which contribute to a sustained sub-population of cells with increased efflux expression activity, potentially conferring a continuous pool of intrinsically resistant bacteria. This modelling approach thus reveals an important source of heterogeneity in cell responses to antimicrobials and sheds light on potentially targetable aspects of efflux pump-related antimicrobial resistance.
Collapse
Affiliation(s)
- Ryan Kerr
- School of Mathematics, University of Birmingham, Birmingham, UK.,Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Sara Jabbari
- School of Mathematics, University of Birmingham, Birmingham, UK.,Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Jessica M A Blair
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Iain G Johnston
- Department of Mathematics, Faculty of Mathematics and Natural Sciences, University of Bergen, Bergen, Norway.,Computational Biology Unit, University of Bergen, Bergen, Norway.,CAMRIA Centre for Antimicrobial Resistance, Vestland, Norway
| |
Collapse
|
34
|
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
|
35
|
Singh P, Verma RK, Chatterjee S. The diffusible signal factor synthase, RpfF, in Xanthomonas oryzae pv. oryzae is required for the maintenance of membrane integrity and virulence. MOLECULAR PLANT PATHOLOGY 2022; 23:118-132. [PMID: 34704368 PMCID: PMC8659556 DOI: 10.1111/mpp.13148] [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: 07/13/2021] [Revised: 09/03/2021] [Accepted: 09/24/2021] [Indexed: 05/12/2023]
Abstract
The Xanthomonas group of phytopathogens communicate with a fatty acid-like cell-cell signalling molecule, cis-11-2-methyl-dodecenoic acid, also known as diffusible signal factor (DSF). In the pathogen of rice, Xanthomonas oryzae pv. oryzae, DSF is involved in the regulation of several virulence-associated functions, including production and secretion of several cell wall hydrolysing type II secretion effectors. To understand the role of DSF in the secretion of type II effectors, we characterized DSF synthase-deficient (rpfF) and DSF-deficient, type II secretion (xpsE) double mutants. Mutant analysis by expression analysis, secretion assay, fatty acid analysis, and physiological studies indicated that rpfF mutants exhibit hypersecretion of several type II effectors due to a perturbed membrane and DSF is required for maintaining membrane integrity. The rpfF mutants exhibited significantly higher uptake of 1-N-phenylnapthylamine and ethidium bromide, and up-regulation of rpoE (σE ). Increasing the osmolarity of the medium could rescue the hypersecretion phenotype of the rpfF mutant. The rpfF mutant exhibited highly reduced virulence. We report for the first time that in X. oryzae pv. oryzae RpfF is involved in the maintenance of membrane integrity by playing a regulatory role in the fatty acid synthesis pathway.
Collapse
Affiliation(s)
- Prashantee Singh
- Laboratory of Plant Microbe InteractionsCentre for DNA Fingerprinting and DiagnosticsUppalIndia
- Graduate StudiesManipal Academy of Higher EducationMangaluruIndia
| | - Raj Kumar Verma
- Laboratory of Plant Microbe InteractionsCentre for DNA Fingerprinting and DiagnosticsUppalIndia
| | - Subhadeep Chatterjee
- Laboratory of Plant Microbe InteractionsCentre for DNA Fingerprinting and DiagnosticsUppalIndia
| |
Collapse
|
36
|
Evaluation of Heterocyclic Carboxamides as Potential Efflux Pump Inhibitors in Pseudomonas aeruginosa. Antibiotics (Basel) 2021; 11:antibiotics11010030. [PMID: 35052908 PMCID: PMC8772707 DOI: 10.3390/antibiotics11010030] [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: 11/05/2021] [Revised: 12/20/2021] [Accepted: 12/23/2021] [Indexed: 12/19/2022] Open
Abstract
The ability to rescue the activity of antimicrobials that are no longer effective against bacterial pathogens such as Pseudomonas aeruginosa is an attractive strategy to combat antimicrobial drug resistance. Herein, novel efflux pump inhibitors (EPIs) demonstrating strong potentiation in combination with levofloxacin against wild-type P. aeruginosa ATCC 27853 are presented. A structure activity relationship of aryl substituted heterocyclic carboxamides containing a pentane diamine side chain is described. Out of several classes of fused heterocyclic carboxamides, aryl indole carboxamide compound 6j (TXA01182) at 6.25 µg/mL showed 8-fold potentiation of levofloxacin. TXA01182 was found to have equally synergistic activities with other antimicrobial classes (monobactam, fluoroquinolones, sulfonamide and tetracyclines) against P. aeruginosa. Several biophysical and genetic studies rule out membrane disruption and support efflux inhibition as the mechanism of action (MOA) of TXA01182. TXA01182 was determined to lower the frequency of resistance (FoR) of the partner antimicrobials and enhance the killing kinetics of levofloxacin. Furthermore, TXA01182 demonstrated a synergistic effect with levofloxacin against several multidrug resistant P. aeruginosa clinical isolates.
Collapse
|
37
|
Roy S, Bahar AA, Gu H, Nangia S, Sauer K, Ren D. Persister control by leveraging dormancy associated reduction of antibiotic efflux. PLoS Pathog 2021; 17:e1010144. [PMID: 34890435 PMCID: PMC8716142 DOI: 10.1371/journal.ppat.1010144] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 12/29/2021] [Accepted: 11/24/2021] [Indexed: 11/19/2022] Open
Abstract
Persistent bacterial infections do not respond to current antibiotic treatments and thus present a great medical challenge. These conditions have been linked to the formation of dormant subpopulations of bacteria, known as persister cells, that are growth-arrested and highly tolerant to conventional antibiotics. Here, we report a new strategy of persister control and demonstrate that minocycline, an amphiphilic antibiotic that does not require active transport to penetrate bacterial membranes, is effective in killing Escherichia coli persister cells [by 70.8 ± 5.9% (0.53 log) at 100 μg/mL], while being ineffective in killing normal cells. Further mechanistic studies revealed that persister cells have reduced drug efflux and accumulate more minocycline than normal cells, leading to effective killing of this dormant subpopulation upon wake-up. Consistently, eravacycline, which also targets the ribosome but has a stronger binding affinity than minocycline, kills persister cells by 3 logs when treated at 100 μg/mL. In summary, the findings of this study reveal that while dormancy is a well-known cause of antibiotic tolerance, it also provides an Achilles’ heel for controlling persister cells by leveraging dormancy associated reduction of drug efflux. Bacterial persister cells are dormant phenotypic variants that are highly tolerant to most antibiotics; and thus, present a major challenge to infection control. This motivated us to develop new strategies that can specifically target the persister population. It is known that persister formation is associated with reduced membrane potential and cellular activities. Thus, we hypothesize that persister cells have reduced drug efflux compared to normal cells and accumulate more antimicrobial agents that can penetrate the membranes of persister cells. By testing this hypothesis, we developed a new set of criteria for selecting persister control agents and demonstrated effective control of Escherichia coli persister cells by minocycline, rifamycin SV, and eravacycline. Our results revealed that these agents are more effective against persister cells than normal cells and the killing occurred during persister wake-up. Collectively, these results demonstrate a new strategy for persister control by leveraging dormancy associated changes in bacterial physiology. The findings may contribute to future drug discovery and the treatment of persistent infections.
Collapse
Affiliation(s)
- Sweta Roy
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York, United States of America
| | - Ali Adem Bahar
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York, United States of America
| | - Huan Gu
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York, United States of America
| | - Shikha Nangia
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York, United States of America
| | - Karin Sauer
- Department of Biological Sciences, Binghamton University, Binghamton, New York, United States of America
| | - Dacheng Ren
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York, United States of America
- Department of Civil and Environmental Engineering, Syracuse University, Syracuse, New York, United States of America
- Department of Biology, Syracuse University, Syracuse, New York, United States of America
- * E-mail:
| |
Collapse
|
38
|
Chen H, Yang N, Yang Y, Zheng Y, Xu M, Zhang H, Liu Y, Shen W, Li J. Doxofylline Protects Gram-Negative Pathogens against Antibiotic-Mediated Killing. ACS Infect Dis 2021; 7:3241-3253. [PMID: 34851627 DOI: 10.1021/acsinfecdis.1c00417] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Given the growing rate of Gram-negative bacterial infections, antibiotics are now frequently prescribed for various respiratory diseases. Doxofylline is a newer generation xanthine with both bronchodilating and anti-inflammatory activities, but its influence on antibiotics remains poorly understood. Here, we first report the discovery of doxofylline-induced high minimum inhibitory concentrations of antibiotics. We also showed that doxofylline blocked antimicrobial-mediated killing for Gram-negative pathogens in vitro and in murine lung infection models in vivo. By combining efflux pump inhibition tests, gene expression analyses, and using the gene tolC knockout strain, we found that doxofylline positively regulated gene expression of the AcrAB-TolC efflux pump and attenuated the effect of doxofylline on antibacterial activities in ΔtolC mutants. Notably, doxofylline-mediated protection correlated with decreased reactive oxygen species (ROS) production. Collectively, our study indicates that doxofylline protects Gram-negative bacteria from antimicrobial lethality by regulating the AcrAB-TolC efflux pump in a TolC-dependent manner and suppressing antibiotic-induced ROS accumulation. These results suggest caution when using antibiotics alongside doxofylline in clinical treatment.
Collapse
Affiliation(s)
- Haoran Chen
- Department of Infectious Disease, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022, China
| | - Ning Yang
- Department of Infectious Disease, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022, China
| | - Yi Yang
- Department of Infectious Disease, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022, China
| | - Yahong Zheng
- Department of Infectious Disease, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022, China
| | - Mengran Xu
- Department of Infectious Disease, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022, China
| | - Hui Zhang
- Department of Infectious Disease, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022, China
| | - Yanyan Liu
- Department of Infectious Disease, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022, China
- Anhui Center for Surveillance of Bacterial Resistance, Hefei, Anhui 230022, China
- Institute of Bacterial Resistance, Anhui Medical University, Hefei, Anhui 230022, China
| | - Weihua Shen
- Department of Special Clinic, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022, China
| | - Jiabin Li
- Department of Infectious Disease, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022, China
- Department of Molecular Biology, Anhui Center for Surveillance of Bacterial Resistance, Hefei, Anhui 230022, China
- Anhui Center for Surveillance of Bacterial Resistance, Hefei, Anhui 230022, China
- Institute of Bacterial Resistance, Anhui Medical University, Hefei, Anhui 230022, China
| |
Collapse
|
39
|
Melander RJ, Mattingly AE, Melander C. Phenotypic screening of compound libraries as a platform for the identification of antibiotic adjuvants: Identification of colistin adjuvants from a natural product library. Methods Enzymol 2021; 665:153-176. [PMID: 35379433 PMCID: PMC10942738 DOI: 10.1016/bs.mie.2021.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The identification of antibiotic adjuvants, small molecules that potentiate the activity of conventional antibiotics, provides an orthogonal approach to the development of new antibiotics in the fight against drug resistant bacterial infections. Methods to identify novel adjuvants could potentially aid efforts to overcome the increasing prevalence of resistance and stave off the onset of a "post-antibiotic era." Phenotypic whole cell screens allow for the identification of hits with the necessary properties to access their biomolecular target, and may also facilitate the discovery of novel adjuvant targets. A phenotypic screening platform is outlined, in which a natural product library was explored for activity with antibiotics from several mechanistically distinct classes against clinically important bacterial species. General approaches to delineating the mechanism of action of hit compounds identified from phenotypic screens are described, followed by specific approaches to uncovering the mechanism of action of the colistin adjuvants identified from the natural product screen.
Collapse
Affiliation(s)
- Roberta J Melander
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States
| | - Anne E Mattingly
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States
| | - Christian Melander
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States.
| |
Collapse
|
40
|
Casalone E, Vignolini T, Braconi L, Gardini L, Capitanio M, Pavone FS, Giovannelli L, Dei S, Teodori E. Characterization of substituted piperazines able to reverse MDR in Escherichia coli strains overexpressing resistance-nodulation-cell division (RND) efflux pumps. J Antimicrob Chemother 2021; 77:413-424. [PMID: 34747445 DOI: 10.1093/jac/dkab388] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 09/28/2021] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND MDR in bacteria is threatening to public health. Overexpression of efflux pumps is an important cause of MDR. The co-administration of antimicrobial drugs and efflux pump inhibitors (EPIs) is a promising approach to address the problem of MDR. OBJECTIVES To identify new putative EPIs and to characterize their mechanisms of action. METHODS The effects of four selected piperazine derivatives on resistance-nodulation-cell division (RND) pumps was evaluated in Escherichia coli strains overexpressing or not expressing RND pumps by assays aimed at evaluating antibiotic potentiation, membrane functionality, ethidium bromide accumulation and AcrB expression. The cytotoxicity of selected piperazines towards primary cultures of human dermal fibroblasts was also investigated. RESULTS Four molecules enhanced levofloxacin activity against strains overexpressing RND efflux pumps (AcrAB-TolC and AcrEF-TolC), but not against RND pump-deficient strains. They had little effects on membrane potential. Molecule 4 decreased, whereas the other three increased, membrane permeability compared with untreated control cells. The four molecules showed differences in the specificity of interaction with RND efflux pumps, by inactivating the transport of one or more antibiotics, and in the levels of ethidium bromide accumulation and of acrB expression inhibition. CONCLUSIONS Piperazine derivatives are good candidates as inhibitors of RND efflux pumps. They decreased the activity of RND pumps by mixed mechanisms of action. Small structural differences among the molecules can be critical in defining their behaviour.
Collapse
Affiliation(s)
- Enrico Casalone
- Department of Biology, University of Florence, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy
| | - Tiziano Vignolini
- LENS-European Laboratory for Non-Linear Spectroscopy, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy
| | - Laura Braconi
- Department of Neurosciences, Psychology, Drug Research and Child's Health-Section of Pharmaceutical and Nutraceutical Sciences, Via U. Schiff 6, 50019 Sesto Fiorentino, Italy
| | - Lucia Gardini
- LENS-European Laboratory for Non-Linear Spectroscopy, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy.,National Institute of Optics-National Research Council, Largo Fermi 6, 50125 Florence, Italy
| | - Marco Capitanio
- LENS-European Laboratory for Non-Linear Spectroscopy, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy.,Department of Physics and Astronomy, University of Florence, Via Sansone 1, 50019 Sesto Fiorentino, Italy
| | - Francesco S Pavone
- LENS-European Laboratory for Non-Linear Spectroscopy, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy.,National Institute of Optics-National Research Council, Largo Fermi 6, 50125 Florence, Italy.,Department of Physics and Astronomy, University of Florence, Via Sansone 1, 50019 Sesto Fiorentino, Italy
| | - Lisa Giovannelli
- Department of Neurosciences, Psychology, Drug Research and Child's Health-Section of Pharmacology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy
| | - Silvia Dei
- Department of Neurosciences, Psychology, Drug Research and Child's Health-Section of Pharmaceutical and Nutraceutical Sciences, Via U. Schiff 6, 50019 Sesto Fiorentino, Italy
| | - Elisabetta Teodori
- Department of Neurosciences, Psychology, Drug Research and Child's Health-Section of Pharmaceutical and Nutraceutical Sciences, Via U. Schiff 6, 50019 Sesto Fiorentino, Italy
| |
Collapse
|
41
|
Comparison of the Acinetobacter baumannii Reference Strains ATCC 17978 and ATCC 19606 in Antimicrobial Resistance Mediated by the AdeABC Efflux Pump. Antimicrob Agents Chemother 2021; 65:e0057021. [PMID: 34097477 DOI: 10.1128/aac.00570-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Acinetobacter baumannii RND efflux pump AdeABC is regulated by the 2-component regulator AdeRS. In this study, we compared the regulation and expression of AdeABC of the reference strains ATCC 17978 and ATCC 19606. A clearly stronger efflux activity was demonstrated for ATCC 19606. An amino acid substitution at residue 172 of adeS was identified as a potential cause for differential expression of the pump. Therefore, we recommend caution with exclusively using single reference strains for research.
Collapse
|
42
|
Jánosity A, Klančnik A, Kiskó G, Možina SS, Baranyi J. Determining optimum carvacrol treatment as a cardinal value of a secondary model. Int J Food Microbiol 2021; 354:109311. [PMID: 34225033 DOI: 10.1016/j.ijfoodmicro.2021.109311] [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: 06/01/2020] [Revised: 05/06/2021] [Accepted: 06/14/2021] [Indexed: 10/21/2022]
Abstract
Predictive microbiology methods were used to study the effect of carvacrol on the bacterial resistance to antimicrobials. Our objective was to estimate the optimum dose of carvacrol at concentrations below its MIC value (Minimum Inhibitory Concentration). As a fluorescent marker, ethidium bromide (EtBr) was applied to Escherichia coli to acquire raw data. The accumulation of EtBr was measured by its fluorescence signal (Fs), in the unit of RFU (Relative Fluorescence Unit). The temporal change of the fluorescence values, at a constant concentration of carvacrol, was described by a saturation curve (primary model). The difference, within the observation interval, between the fitted initial and maximum fluorescent values was chosen as the primary parameter to be fitted in the secondary model: a convex, asymmetric, bi-linear function of the carvacrol concentration changing between 0 and 0.5 MIC. Its breakpoint is the optimum value of the carvacrol, a cardinal parameter of the secondary model, where the chosen primary parameter assumes its highest value. This optimum was estimated with high uncertainty for individual experiments, but F-test showed that, with appropriate experimental and numerical procedure, its existence and value can be claimed with confidence. Our results demonstrate that the estimation of the optimum of the secondary model can be robust even if the full secondary model is uncertain.
Collapse
Affiliation(s)
- Anna Jánosity
- Department of Food Microbiology, Hygiene and Safety, Hungarian University of Agriculture and Life Sciences, Budapest, Hungary
| | - Anja Klančnik
- Department of Food Science and Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Gabriella Kiskó
- Department of Food Microbiology, Hygiene and Safety, Hungarian University of Agriculture and Life Sciences, Budapest, Hungary
| | - Sonja Smole Možina
- Department of Food Science and Technology, University of Ljubljana, Ljubljana, Slovenia
| | - József Baranyi
- Institute of Nutrition, University of Debrecen, Debrecen, Hungary.
| |
Collapse
|
43
|
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 DOI: 10.1021/acs.chemrev.0c01137] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [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
|
44
|
Beebout CJ, Sominsky LA, Eberly AR, Van Horn GT, Hadjifrangiskou M. Cytochrome bd promotes Escherichia coli biofilm antibiotic tolerance by regulating accumulation of noxious chemicals. NPJ Biofilms Microbiomes 2021; 7:35. [PMID: 33863914 PMCID: PMC8052454 DOI: 10.1038/s41522-021-00210-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 03/16/2021] [Indexed: 02/02/2023] Open
Abstract
Nutrient gradients in biofilms cause bacteria to organize into metabolically versatile communities capable of withstanding threats from external agents including bacteriophages, phagocytes, and antibiotics. We previously determined that oxygen availability spatially organizes respiration in uropathogenic Escherichia coli biofilms, and that the high-affinity respiratory quinol oxidase cytochrome bd is necessary for extracellular matrix production and biofilm development. In this study we investigate the physiologic consequences of cytochrome bd deficiency in biofilms and determine that loss of cytochrome bd induces a biofilm-specific increase in expression of general diffusion porins, leading to elevated outer membrane permeability. In addition, loss of cytochrome bd impedes the proton mediated efflux of noxious chemicals by diminishing respiratory flux. As a result, loss of cytochrome bd enhances cellular accumulation of noxious chemicals and increases biofilm susceptibility to antibiotics. These results identify an undescribed link between E. coli biofilm respiration and stress tolerance, while suggesting the possibility of inhibiting cytochrome bd as an antibiofilm therapeutic approach.
Collapse
Affiliation(s)
- Connor J. Beebout
- grid.412807.80000 0004 1936 9916Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN USA
| | - Levy A. Sominsky
- grid.152326.10000 0001 2264 7217Vanderbilt University, Nashville, TN USA
| | - Allison R. Eberly
- grid.412807.80000 0004 1936 9916Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN USA ,grid.66875.3a0000 0004 0459 167XPresent Address: Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN USA
| | - Gerald T. Van Horn
- grid.412807.80000 0004 1936 9916Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN USA
| | - Maria Hadjifrangiskou
- grid.412807.80000 0004 1936 9916Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN USA ,grid.412807.80000 0004 1936 9916Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN USA
| |
Collapse
|
45
|
Kaur UJ, Chopra A, Preet S, Raj K, Kondepudi KK, Gupta V, Rishi P. Potential of 1-(1-napthylmethyl)-piperazine, an efflux pump inhibitor against cadmium-induced multidrug resistance in Salmonella enterica serovar Typhi as an adjunct to antibiotics. Braz J Microbiol 2021; 52:1303-1313. [PMID: 33851343 DOI: 10.1007/s42770-021-00492-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 04/06/2021] [Indexed: 01/30/2023] Open
Abstract
This study was focused on elucidating inhibition of antibiotic efflux mechanism of cadmium adapted (CdA) Salmonella Typhi Ty2 cells. Herein, upregulated expression of efflux genes (acrB, tolC) and their regulators (soxS, marA) was observed in CdA Ty2 cells by qRT-PCR. The pathogen further elevated the expression of these genes even in the presence of three efflux pump inhibitors (EPIs), i.e., Phe-Arg-β-naphthylamide, 1-(1-naphthyl-methyl)piperazine, and 5-hydroxy-2-methyl-1,4-naphthoquinone, perhaps by sensing the pressure of the latter in addition to cadmium stress. Interaction of different EPIs with efflux pumps of CdA Ty2 cells was confirmed using ethidium bromide (EtBr) accumulation and efflux assay. All the EPIs could cause retention of EtBr which was indicated by increased fluorescence units. Considering this potential of EPIs, retention of antibiotics was evaluated in CdA Ty2 cells wherein EPIs were used in combination with selected antibiotics (instead of EtBr). A decrease in the effective concentration of antibiotics was observed. This was further validated using the clinical isolates. The data revealed the efficiency of EPIs as they could inhibit the efflux potential of even the overexpressed efflux pumps. Thus, combination of EPI(s)-antibiotics may be exploited in future as one of the strategies for combating metal induced antibiotic resistance.
Collapse
Affiliation(s)
- Ujjwal Jit Kaur
- Department of Microbiology, Panjab University, Chandigarh, India
| | - Adity Chopra
- Department of Microbiology, Panjab University, Chandigarh, India
| | - Simran Preet
- Department of Biophysics, Panjab University, Chandigarh, India
| | - Khem Raj
- Department of Microbiology, Panjab University, Chandigarh, India
| | | | - Varsha Gupta
- Government Medical College and Hospital, Sector- 32, Chandigarh, India
| | - Praveen Rishi
- Department of Microbiology, Panjab University, Chandigarh, India.
| |
Collapse
|
46
|
A Major Facilitator Superfamily (MFS) Efflux Pump, SCO4121, from Streptomyces coelicolor with Roles in Multidrug Resistance and Oxidative Stress Tolerance and Its Regulation by a MarR Regulator. Appl Environ Microbiol 2021; 87:AEM.02238-20. [PMID: 33483304 DOI: 10.1128/aem.02238-20] [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: 09/12/2020] [Accepted: 01/12/2021] [Indexed: 12/12/2022] Open
Abstract
Overexpression of efflux pumps is one of the major determinants of resistance in bacteria. Streptomyces species harbor a large array of efflux pumps that are transcriptionally silenced under laboratory conditions. However, their dissemination results in multidrug resistance in different clinical pathogens. In this study, we have identified an efflux pump from Streptomyces coelicolor, SCO4121, belonging to the major facilitator superfamily (MFS) family of transporters and characterized its role in antibiotic resistance. SCO4121 provided resistance to multiple dissimilar drugs upon overexpression in both native and heterologous hosts. Further, deletion of SCO4121 resulted in increased sensitivity toward ciprofloxacin and chloramphenicol, suggesting the pump to be a major transporter of these substrates. Apart from providing multidrug resistance, SCO4121 imparted increased tolerance against the strong oxidant HOCl. In wild-type Streptomyces coelicolor cells, these drugs were found to transcriptionally regulate the pump in a concentration-dependent manner. Additionally, we identified SCO4122, a MarR regulator that positively regulates SCO4121 in response to various drugs and the oxidant HOCl. Thus, through these studies we present the multiple roles of SCO4121 in S. coelicolor and highlight the intricate mechanisms via which it is regulated in response to antibiotics and oxidative stress.IMPORTANCE One of the key mechanisms of drug resistance in bacteria is overexpression of efflux pumps. Streptomyces species are a reservoir of a large number of efflux pumps, potentially to provide resistance to both endogenous and nonendogenous antibiotics. While many of these pumps are not expressed under standard laboratory conditions, they result in resistance to multiple drugs when spread to other bacterial pathogens through horizontal gene transfer. In this study, we have identified a widely conserved efflux pump SCO4121 from Streptomyces coelicolor with roles in both multidrug resistance and oxidative stress tolerance. We also report the presence of an adjacent MarR regulator, SCO4122, which positively regulates SCO4121 in the presence of diverse substrates in a redox-responsive manner. This study highlights that soil bacteria such as Streptomyces can reveal novel mechanisms of antibiotic resistance that may potentially emerge in clinically important bacteria.
Collapse
|
47
|
Branska B, Vasylkivska M, Raschmanova H, Jureckova K, Sedlar K, Provaznik I, Patakova P. Changes in efflux pump activity of Clostridium beijerinckii throughout ABE fermentation. Appl Microbiol Biotechnol 2021; 105:877-889. [PMID: 33409609 DOI: 10.1007/s00253-020-11072-2] [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: 04/08/2020] [Revised: 12/05/2020] [Accepted: 12/17/2020] [Indexed: 01/08/2023]
Abstract
Pumping toxic substances through a cytoplasmic membrane by protein transporters known as efflux pumps represents one bacterial mechanism involved in the stress response to the presence of toxic compounds. The active efflux might also take part in exporting low-molecular-weight alcohols produced by intrinsic cell metabolism; in the case of solventogenic clostridia, predominantly acetone, butanol and ethanol (ABE). However, little is known about this active efflux, even though some evidence exists that membrane pumps might be involved in solvent tolerance. In this study, we investigated changes in overall active efflux during ABE fermentation, employing a flow cytometric protocol adjusted for Clostridia and using ethidium bromide (EB) as a fluorescence marker for quantification of direct efflux. A fluctuation in efflux during the course of standard ABE fermentation was observed, with a maximum reached during late acidogenesis, a high efflux rate during early and mid-solventogenesis and an apparent decrease in EB efflux rate in late solventogenesis. The fluctuation in efflux activity was in accordance with transcriptomic data obtained for various membrane exporters in a former study. Surprisingly, under altered cultivation conditions, when solvent production was attenuated, and extended acidogenesis was promoted, stable low efflux activity was reached after an initial peak that appeared in the stage comparable to standard ABE fermentation. This study confirmed that efflux pump activity is not constant during ABE fermentation and suggests that undisturbed solvent production might be a trigger for activation of pumps involved in solvent efflux. KEY POINTS: • Flow cytometric assay for efflux quantification in Clostridia was established. • Efflux rate peaked in late acidogenesis and in early solventogenesis. • Impaired solventogenesis led to an overall decrease in efflux.
Collapse
Affiliation(s)
- Barbora Branska
- Department of Biotechnology, University of Chemistry and Technology Prague, Technicka 5, 166 28, Prague, Czech Republic.
| | - Maryna Vasylkivska
- Department of Biotechnology, University of Chemistry and Technology Prague, Technicka 5, 166 28, Prague, Czech Republic
| | - Hana Raschmanova
- Department of Biotechnology, University of Chemistry and Technology Prague, Technicka 5, 166 28, Prague, Czech Republic
| | - Katerina Jureckova
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 12, 616 00, Brno, Czech Republic
| | - Karel Sedlar
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 12, 616 00, Brno, Czech Republic
| | - Ivo Provaznik
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 12, 616 00, Brno, Czech Republic
| | - Petra Patakova
- Department of Biotechnology, University of Chemistry and Technology Prague, Technicka 5, 166 28, Prague, Czech Republic
| |
Collapse
|
48
|
Abstract
Mycobacteria are intrinsically resistant to most antimicrobials, which is generally attributed to the impermeability of their cell wall that considerably limits drug uptake. Moreover, like in other pathogenic bacteria, active efflux systems have been widely characterized from diverse mycobacterial species in laboratory conditions, showing that they can promote resistance by extruding noxious compounds prior to their reaching their intended targets. Therefore, the intracellular concentration of a given compound is determined by the balance between permeability, influx, and efflux.Given the urgent need to discover and develop novel antimycobacterial compounds in order to design effective therapeutic strategies, the contributions to drug resistance made by the controlled permeability of the cell wall and the increased activity of efflux pumps must be determined. In this chapter, we will describe a method that allows (1) the measuring of permeability and the quantification of general efflux activity of mycobacteria, by the study of the transport (influx and efflux) of fluorescent compounds, such as ethidium bromide; and (2) the screening of compounds in search of agents that increase the permeability of the cell wall and efflux inhibitors that could restore the effectiveness of antimicrobials that are subject to efflux.
Collapse
|
49
|
Zhao S, Adamiak JW, Bonifay V, Mehla J, Zgurskaya HI, Tan DS. Defining new chemical space for drug penetration into Gram-negative bacteria. Nat Chem Biol 2020; 16:1293-1302. [PMID: 33199906 PMCID: PMC7897441 DOI: 10.1038/s41589-020-00674-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 09/11/2020] [Indexed: 12/24/2022]
Abstract
We live in the era of antibiotic resistance, and this problem will progressively worsen if no new solutions emerge. In particular, Gram-negative pathogens present both biological and chemical challenges that hinder the discovery of new antibacterial drugs. First, these bacteria are protected from a variety of structurally diverse drugs by a low-permeability barrier composed of two membranes with distinct permeability properties, in addition to active drug efflux, making this cell envelope impermeable to most compounds. Second, chemical libraries currently used in drug discovery contain few compounds that can penetrate Gram-negative bacteria. As a result of these challenges, intensive screening campaigns have led to few successes, highlighting the need for new approaches to identify regions of chemical space that are specifically relevant to antibacterial drug discovery. Herein we provide an overview of emerging insights into this problem and outline a general approach to addressing it using prospective analysis of chemical libraries for the ability of compounds to accumulate in Gram-negative bacteria. The overall goal is to develop robust cheminformatic tools to predict Gram-negative permeation and efflux, which can then be used to guide medicinal chemistry campaigns and the design of antibacterial discovery libraries.
Collapse
Affiliation(s)
- Shibin Zhao
- Chemical Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Justyna W Adamiak
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Vincent Bonifay
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Jitender Mehla
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Helen I Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA.
| | - Derek S Tan
- Chemical Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Tri-Institutional Research Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
| |
Collapse
|
50
|
Hafeezunnisa M, Sen R. The Rho-Dependent Transcription Termination Is Involved in Broad-Spectrum Antibiotic Susceptibility in Escherichia coli. Front Microbiol 2020; 11:605305. [PMID: 33329496 PMCID: PMC7734253 DOI: 10.3389/fmicb.2020.605305] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 11/10/2020] [Indexed: 01/19/2023] Open
Abstract
One of the major ways of acquiring multidrug resistance in bacteria is via drug influx and efflux pathways. Here, we show that E. coli with compromised Rho-dependent transcription termination function has enhanced broad-spectrum antibiotic susceptibility, which arises from the inefficient TolC-efflux process and increased permeability of the membrane. The Rho mutants have altered morphology, distinct cell surface, and increased levels of lipopolysaccharide in their outer membrane, which might have rendered the TolC efflux pumps inefficient. These alterations are due to the upregulations of poly-N-acetyl-glucosamine and lipopolysaccharide synthesis operons because of inefficient Rho functions. The Rho mutants are capable of growing on various dipeptides and carbohydrate sources, unlike their WT counterpart. Dipeptides uptake arises from the upregulations of the di-peptide permease operon in these mutants. The metabolomics of the Rho mutants revealed the presence of a high level of novel metabolites. Accumulation of these metabolites in these Rho mutants might titrate out the TolC-efflux pumps, which could further reduce their efficiency. We conclude that the transcription termination factor, Rho, regulates the broad-spectrum antibiotic susceptibility of E. coli through multipartite pathways in a TolC-dependent manner. The involvement of Rho-dependent termination in multiple pathways and its association with antibiotic susceptibility should make Rho-inhibitors useful in the anti-bacterial treatment regimen.
Collapse
Affiliation(s)
- Md Hafeezunnisa
- Laboratory of Transcription, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India.,Graduate Studies, Manipal Academy of Higher Education, Manipal, India
| | - Ranjan Sen
- Laboratory of Transcription, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
| |
Collapse
|