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Mikuni-Mester P, Robben C, Witte AK, Linke K, Ehling-Schulz M, Rossmanith P, Grunert T. Antimicrobial Ionic Liquids: Ante-Mortem Mechanisms of Pathogenic EPEC and MRSA Examined by FTIR Spectroscopy. Int J Mol Sci 2024; 25:4705. [PMID: 38731923 PMCID: PMC11083031 DOI: 10.3390/ijms25094705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 04/22/2024] [Accepted: 04/22/2024] [Indexed: 05/13/2024] Open
Abstract
Ionic liquids (ILs) have gained considerable attention due to their versatile and designable properties. ILs show great potential as antibacterial agents, but understanding the mechanism of attack on bacterial cells is essential to ensure the optimal design of IL-based biocides. The final aim is to achieve maximum efficacy while minimising toxicity and preventing resistance development in target organisms. In this study, we examined a dose-response analysis of ILs' antimicrobial activity against two pathogenic bacteria with different Gram types in terms of molecular responses on a cellular level using Fourier-transform infrared (FTIR) spectroscopy. In total, 18 ILs with different antimicrobial active motifs were evaluated on the Gram-negative enteropathogenic Escherichia coli (EPEC) and Gram-positive methicillin-resistant Staphylococcus aureus (MRSA). The results showed that most ILs impact bacterial proteins with increasing concentration but have a minimal effect on cellular membranes. Dose-response spectral analysis revealed a distinct ante-mortem response against certain ILs for MRSA but not for EPEC. We found that at sub-lethal concentrations, MRSA actively changed their membrane composition to counteract the damaging effect induced by the ILs. This suggests a new adaptive mechanism of Gram-positive bacteria against ILs and demonstrates the need for a better understanding before using such substances as novel antimicrobials.
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Affiliation(s)
- Patrick Mikuni-Mester
- Centre for Food Science and Veterinary Public Health, Unit of Food Microbiology, Clinical Department for Farm Animals and Food System Science, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria;
- FFoQSI—Austrian Competence Centre for Feed and Food Quality, Safety & Innovation, Technopark 1D, 3430 Tulln, Austria
| | - Christian Robben
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria;
| | - Anna K. Witte
- HTK Hygiene Technologie Kompetenzzentrum GmbH, Buger Str. 80, 96049 Bamberg, Germany;
| | - Kristina Linke
- ZuchtData EDV-Dienstleistungen GmbH, Dresdner Str. 89/18, 1200 Vienna, Austria;
| | - Monika Ehling-Schulz
- Centre of Pathobiology, Functional Microbiology Division, Department of Biological Sciences and Pathobiology, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria; (M.E.-S.); (T.G.)
| | - Peter Rossmanith
- Centre for Food Science and Veterinary Public Health, Unit of Food Microbiology, Clinical Department for Farm Animals and Food System Science, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria;
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria;
| | - Tom Grunert
- Centre of Pathobiology, Functional Microbiology Division, Department of Biological Sciences and Pathobiology, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria; (M.E.-S.); (T.G.)
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Mester P, Robben C, Witte AK, Kalb R, Ehling-Schulz M, Rossmanith P, Grunert T. FTIR Spectroscopy Suggests a Revised Mode of Action for the Cationic Side-Chain Effect of Ionic Liquids. ACS COMBINATORIAL SCIENCE 2019; 21:90-97. [PMID: 30596487 DOI: 10.1021/acscombsci.8b00141] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Over the past decades, ionic liquids (ILs) have gained considerable attention from the scientific community because of their versatile and designable properties. As a result, there are numerous IL applications, not only in organic synthesis, catalysis, or extraction but also as active pharmaceutical ingredients or novel antimicrobials. While considerable effort has been put into developing quantitative structure-activity relationship (QSAR) models for IL toxicity prediction, little is known about their actual mode of action. In this study, Fourier transform infrared (FTIR) spectroscopy is used to monitor IL induced molecular responses directly at the cellular level. Investigation of the well-known cationic alkyl side-chain effect (increasing side-chain length leads to increasing toxicity) of imidazolium- and ammonium-based ILs on two bacterial pathogens, enteropathogenic Escherichia coli (EPEC) and methicillin-resistant Staphylococcus aureus (MRSA), surprisingly revealed two distinct modes of action. Contrary to prior models, it was only for [TMC16A][Cl], where a molecular response in the membrane was found, while ILs with shorter side-chain lengths predominantly affected bacterial proteins. The results of this study highlight the importance of further direct investigations of the impact of ILs at the cellular level to improve toxicity prediction and assess the usefulness of spectroscopic methods, such as FTIR spectroscopy at achieving this goal.
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Affiliation(s)
- Patrick Mester
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria
| | - Christian Robben
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria
| | - Anna K. Witte
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria
| | - Roland Kalb
- Proionic GmbH, Parkring 18, 8074 Grambach, Austria
| | - Monika Ehling-Schulz
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria
| | - Peter Rossmanith
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria
- Institute of Milk Hygiene, Milk Technology and Food Science, Department of Veterinary Public Health and Food Science, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria
| | - Tom Grunert
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria
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Virucidal or Not Virucidal? That Is the Question-Predictability of Ionic Liquid's Virucidal Potential in Biological Test Systems. Int J Mol Sci 2018. [PMID: 29522483 PMCID: PMC5877651 DOI: 10.3390/ijms19030790] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
For three decades now, ionic liquids (ILs), organic salts comprising only ions, have emerged as a new class of pharmaceuticals. Although recognition of the antimicrobial effects of ILs is growing rapidly, there is almost nothing known about their possible virucidal activities. This probably reflects the paucity of understanding virus inactivation. In this study, we performed a systematic analysis to determine the effect of specific structural motifs of ILs on three different biological test systems (viruses, bacteria and enzymes). Overall, the effects of 27 different ILs on two non-enveloped and one enveloped virus (P100, MS2 and Phi6), two Gram negative and one Gram positive bacteria (E. coli, P. syringae and L. monocytogenes) and one enzyme (Taq DNA polymerase) were investigated. Results show that while some ILs were virucidal, no clear structure activity relationships (SARs) could be identified for the non-enveloped viruses P100 and MS2. However, for the first time, a correlation has been demonstrated between the effects of ILs on enveloped viruses, bacteria and enzyme inhibition. These identified SARs serve as a sound starting point for further studies.
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Fister S, Mester P, Sommer J, Witte AK, Kalb R, Wagner M, Rossmanith P. Virucidal Influence of Ionic Liquids on Phages P100 and MS2. Front Microbiol 2017; 8:1608. [PMID: 28883814 PMCID: PMC5573800 DOI: 10.3389/fmicb.2017.01608] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 08/07/2017] [Indexed: 11/13/2022] Open
Abstract
An increasing number of publications describe the potential of ionic liquids (ILs) as novel antimicrobials, antibacterial coatings and even as active pharmaceutical ingredients. Nevertheless, a major research area, notably their impact on viruses, has so far been neglected. Consequently the aim of this study was to examine the effects of ILs on the infectivity of viruses. A systematic analysis to investigate the effects of defined structural elements of ILs on virus activity was performed using 55 ILs. All structure activity relationships (SARs) were tested on the human norovirus surrogate phage MS2 and phage P100 representing non-enveloped DNA viruses. Results demonstrate that IL SAR conclusions, established for prokaryotes and eukaryotes, are not readily applicable to the examined phages. A virus-type-dependent IL influence was also apparent. Overall, four ILs, covering different structural elements, were found to reduce phage P100 infectivity by ≥4 log10 units, indicating a virucidal effect, whereas the highest reduction for phage MS2 was about 3 log10 units. Results indicate that future applications of ILs as virucidal agents will require development of novel SARs and the obtained results serve as a good starting point for future studies.
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Affiliation(s)
- Susanne Fister
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Institute for Milk Hygiene, Milk Technology and Food Science, Department for Farm Animals and Public Veterinary Health, University of Veterinary MedicineVienna, Austria
| | - Patrick Mester
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Institute for Milk Hygiene, Milk Technology and Food Science, Department for Farm Animals and Public Veterinary Health, University of Veterinary MedicineVienna, Austria
| | - Julia Sommer
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Institute for Milk Hygiene, Milk Technology and Food Science, Department for Farm Animals and Public Veterinary Health, University of Veterinary MedicineVienna, Austria
| | - Anna K Witte
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Institute for Milk Hygiene, Milk Technology and Food Science, Department for Farm Animals and Public Veterinary Health, University of Veterinary MedicineVienna, Austria
| | - Roland Kalb
- Proionic Production of Ionic Substances GmbHGrambach, Austria
| | - Martin Wagner
- Institute for Milk Hygiene, Milk Technology and Food Science, Department for Farm Animals and Public Veterinary Health, University of Veterinary MedicineVienna, Austria
| | - Peter Rossmanith
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Institute for Milk Hygiene, Milk Technology and Food Science, Department for Farm Animals and Public Veterinary Health, University of Veterinary MedicineVienna, Austria.,Institute for Milk Hygiene, Milk Technology and Food Science, Department for Farm Animals and Public Veterinary Health, University of Veterinary MedicineVienna, Austria
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Mester P, Jehle AK, Leeb C, Kalb R, Grunert T, Rossmanith P. FTIR metabolomic fingerprint reveals different modes of action exerted by active pharmaceutical ingredient based ionic liquids (API-ILs) on Salmonella typhimurium. RSC Adv 2016. [DOI: 10.1039/c5ra24970h] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
FTIR spectroscopic analysis of two IL species with similar high antimicrobial activity ([TC8MA]/[TMC16A]) revealed independently of their anion different modes of action against S. typhimurium through alterations in the bacterial membrane fluidity.
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Affiliation(s)
- P. Mester
- Department of Veterinary Public Health and Food Science
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants
- University of Veterinary Medicine
- 1210 Vienna
- Austria
| | - A. K. Jehle
- Department of Veterinary Public Health and Food Science
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants
- University of Veterinary Medicine
- 1210 Vienna
- Austria
| | - C. Leeb
- Department of Veterinary Public Health and Food Science
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants
- University of Veterinary Medicine
- 1210 Vienna
- Austria
| | - R. Kalb
- Proionic Production of Ionic Substances GmbH
- 8074 Grambach
- Austria
| | - T. Grunert
- Department of Pathobiology
- Functional Microbiology
- Institute of Microbiology
- University of Veterinary Medicine
- 1210 Vienna
| | - P. Rossmanith
- Department of Veterinary Public Health and Food Science
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants
- University of Veterinary Medicine
- 1210 Vienna
- Austria
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