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Dashtbani-Roozbehani A, Brown MH. Efflux Pump Mediated Antimicrobial Resistance by Staphylococci in Health-Related Environments: Challenges and the Quest for Inhibition. Antibiotics (Basel) 2021; 10:antibiotics10121502. [PMID: 34943714 PMCID: PMC8698293 DOI: 10.3390/antibiotics10121502] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 11/30/2021] [Accepted: 11/30/2021] [Indexed: 01/04/2023] Open
Abstract
The increasing emergence of antimicrobial resistance in staphylococcal bacteria is a major health threat worldwide due to significant morbidity and mortality resulting from their associated hospital- or community-acquired infections. Dramatic decrease in the discovery of new antibiotics from the pharmaceutical industry coupled with increased use of sanitisers and disinfectants due to the ongoing COVID-19 pandemic can further aggravate the problem of antimicrobial resistance. Staphylococci utilise multiple mechanisms to circumvent the effects of antimicrobials. One of these resistance mechanisms is the export of antimicrobial agents through the activity of membrane-embedded multidrug efflux pump proteins. The use of efflux pump inhibitors in combination with currently approved antimicrobials is a promising strategy to potentiate their clinical efficacy against resistant strains of staphylococci, and simultaneously reduce the selection of resistant mutants. This review presents an overview of the current knowledge of staphylococcal efflux pumps, discusses their clinical impact, and summarises compounds found in the last decade from plant and synthetic origin that have the potential to be used as adjuvants to antibiotic therapy against multidrug resistant staphylococci. Critically, future high-resolution structures of staphylococcal efflux pumps could aid in design and development of safer, more target-specific and highly potent efflux pump inhibitors to progress into clinical use.
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Szultka-Młyńska M, Janiszewska D, Pomastowski P, Złoch M, Kupczyk W, Buszewski B. Identification of Bacteria Associated with Post-Operative Wounds of Patients with the Use of Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry Approach. Molecules 2021; 26:5007. [PMID: 34443592 PMCID: PMC8402041 DOI: 10.3390/molecules26165007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/13/2021] [Accepted: 08/16/2021] [Indexed: 11/25/2022] Open
Abstract
The bacterial infection of post-operative wounds is a common health problem. Therefore, it is important to investigate fast and accurate methods of identifying bacteria in clinical samples. The aim of the study was to analyse the use of the MALDI-TOF MS technique to identify microorganism wounds that are difficult to heal. The most common bacteria are Escherichia coli, Staphylococcus spp., and Enterococcus spp. We also demonstrate the effect of culture conditions, such as the used growth medium (solid: Brain Heart Infusion Agar, Mueller Hilton Agar, Glucose Bromocresol Purple Agar, and Vancomycin Resistance Enterococci Agar Base and liquid: Tryptic Soy Broth and BACTEC Lytic/10 Anaerobic/F), the incubation time (4, 6, and 24h), and the method of the preparation of bacterial protein extracts (the standard method based on the Bruker guideline, the Sepsityper method) to identify factors and the quality of the obtained mass spectra. By comparing the protein profiles of bacteria from patients not treated with antibiotics to those treated with antibiotics based on the presence/absence of specific signals and using the UniProt platform, it was possible to predict the probable mechanism of the action of the antibiotic used and the mechanism of drug resistance.
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Affiliation(s)
- Małgorzata Szultka-Młyńska
- Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, Gagarin 7, 87-100 Torun, Poland; (D.J.); (B.B.)
| | - Daria Janiszewska
- Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, Gagarin 7, 87-100 Torun, Poland; (D.J.); (B.B.)
| | - Paweł Pomastowski
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Wilenska 4, 87-100 Torun, Poland; (P.P.); (M.Z.)
| | - Michał Złoch
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Wilenska 4, 87-100 Torun, Poland; (P.P.); (M.Z.)
| | - Wojciech Kupczyk
- Department of General, Gastroenterological and Oncological Surgery, Collegium Medicum, Nicolaus Copernicus University, 87-100 Torun, Poland;
| | - Bogusław Buszewski
- Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, Gagarin 7, 87-100 Torun, Poland; (D.J.); (B.B.)
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Wilenska 4, 87-100 Torun, Poland; (P.P.); (M.Z.)
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3
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Wu L, Wu ZC, Todosiichuk T, Korneva O. Nosocomial Infections: Pathogenicity, Resistance and Novel Antimicrobials. INNOVATIVE BIOSYSTEMS AND BIOENGINEERING 2021. [DOI: 10.20535/ibb.2021.5.2.228970] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Background. The fight against the spread of infectious diseases creates the problem of resistance to pathogens and the most resistant of them – the propagators of nosocomial infections – are formed in hospitals because of a number of reasons. The solution of the problem lies in different areas, but the search of new effective means for the treatment of such diseases remains relevant right today. The shortest way to do this is to find the "pain points" of the pathogens themselves, i.e. the factors of their pathogenicity and resistance to which the action of novel antiseptics should be directed.
Objective. We aimed to analyse and evaluate the main factors of pathogenicity and resistance of pathogens of nosocomial infections to determine modern approaches to the development of novel antimicrobials.
Methods. Search and systematization of new scientific data and results concerning pathogenic factors of microbial pathogens that can be used as targets for the action of drugs.
Results. Over the last 10–20 years, due to the development of new research methods in biology, it has become possible to clarify the features and additional conditions for the detection of pathogenic factors of nosocomial infections. Additional mechanisms of manifestation of resistance, adhesiveness, invasiveness, transmission of signs, secretion of toxins by pathogens are shownthat determines the general increase of their resistance to the action of currently used means. The general idea of creating antiseptics that will not increase the resistance of pathogens can now be implemented by using substances with multidirectional or indirect mechanisms of action that minimally affect the metabolism of the cell and significantly reduce its resistance and pathogenicity.
Conclusions. Factors of pathogenicity of propagators of nosocomial infections and mechanisms of their implementation can be considered as the main targets for the action of novel antiseptics that will inhibit the spread of pathogens without increasing their resistance. The promising substances for such drugs, among other things, are bacteriophages and their modifications, enzybiotics, immunobiotics, autoinducer inhibitors, quorum sensing-system inhibitors, b-lactamase inhibitors and others. Some of these substances in combination with the new generation of antibiotics significantly enhance their effectiveness and together they are able to overcome the resistance of even multidrug-resistant pathogens.
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Henderson PJF, Maher C, Elbourne LDH, Eijkelkamp BA, Paulsen IT, Hassan KA. Physiological Functions of Bacterial "Multidrug" Efflux Pumps. Chem Rev 2021; 121:5417-5478. [PMID: 33761243 DOI: 10.1021/acs.chemrev.0c01226] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bacterial multidrug efflux pumps have come to prominence in human and veterinary pathogenesis because they help bacteria protect themselves against the antimicrobials used to overcome their infections. However, it is increasingly realized that many, probably most, such pumps have physiological roles that are distinct from protection of bacteria against antimicrobials administered by humans. Here we undertake a broad survey of the proteins involved, allied to detailed examples of their evolution, energetics, structures, chemical recognition, and molecular mechanisms, together with the experimental strategies that enable rapid and economical progress in understanding their true physiological roles. Once these roles are established, the knowledge can be harnessed to design more effective drugs, improve existing microbial production of drugs for clinical practice and of feedstocks for commercial exploitation, and even develop more sustainable biological processes that avoid, for example, utilization of petroleum.
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Affiliation(s)
- Peter J F Henderson
- School of Biomedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Claire Maher
- School of Environmental and Life Sciences, University of Newcastle, Callaghan 2308, New South Wales, Australia
| | - Liam D H Elbourne
- Department of Biomolecular Sciences, Macquarie University, Sydney 2109, New South Wales, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney 2019, New South Wales, Australia
| | - Bart A Eijkelkamp
- College of Science and Engineering, Flinders University, Bedford Park 5042, South Australia, Australia
| | - Ian T Paulsen
- Department of Biomolecular Sciences, Macquarie University, Sydney 2109, New South Wales, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney 2019, New South Wales, Australia
| | - Karl A Hassan
- School of Environmental and Life Sciences, University of Newcastle, Callaghan 2308, New South Wales, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney 2019, New South Wales, Australia
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5
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Ribič U, Jakše J, Toplak N, Koren S, Kovač M, Klančnik A, Jeršek B. Transporters and Efflux Pumps Are the Main Mechanisms Involved in Staphylococcus epidermidis Adaptation and Tolerance to Didecyldimethylammonium Chloride. Microorganisms 2020; 8:E344. [PMID: 32121333 PMCID: PMC7143832 DOI: 10.3390/microorganisms8030344] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 02/27/2020] [Accepted: 02/28/2020] [Indexed: 01/28/2023] Open
Abstract
Staphylococcus epidermidis cleanroom strains are often exposed to sub-inhibitory concentrations of disinfectants, including didecyldimethylammonium chloride (DDAC). Consequently, they can adapt or even become tolerant to them. RNA-sequencing was used to investigate adaptation and tolerance mechanisms of S. epidermidis cleanroom strains (SE11, SE18), with S. epidermidis SE11Ad adapted and S. epidermidis SE18To tolerant to DDAC. Adaptation to DDAC was identified with up-regulation of genes mainly involved in transport (thioredoxin reductase [pstS], the arsenic efflux pump [gene ID, SE0334], sugar phosphate antiporter [uhpT]), while down-regulation was seen for the Agr system (agrA, arC, agrD, psm, SE1543), for enhanced biofilm formation. Tolerance to DDAC revealed the up-regulation of genes associated with transporters (L-cysteine transport [tcyB]; uracil permease [SE0875]; multidrug transporter [lmrP]; arsenic efflux pump [arsB]); the down-regulation of genes involved in amino-acid biosynthesis (lysine [dapE]; histidine [hisA]; methionine [metC]), and an enzyme involved in peptidoglycan, and therefore cell wall modifications (alanine racemase [SE1079]). We show for the first time the differentially expressed genes in DDAC-adapted and DDAC-tolerant S. epidermidis strains, which highlight the complexity of the responses through the involvement of different mechanisms.
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Affiliation(s)
- Urška Ribič
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia; (U.R.); (A.K.)
| | - Jernej Jakše
- Department of Agronomy, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia;
| | - Nataša Toplak
- Omega d.o.o., Dolinškova 8, SI-1000 Ljubljana, Slovenia; (N.T.); (S.K.); (M.K.)
| | - Simon Koren
- Omega d.o.o., Dolinškova 8, SI-1000 Ljubljana, Slovenia; (N.T.); (S.K.); (M.K.)
| | - Minka Kovač
- Omega d.o.o., Dolinškova 8, SI-1000 Ljubljana, Slovenia; (N.T.); (S.K.); (M.K.)
| | - Anja Klančnik
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia; (U.R.); (A.K.)
| | - Barbara Jeršek
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia; (U.R.); (A.K.)
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Ribič U, Polak T, Lušnic Polak M, Klančnik A, Jeršek B. Adaptation Response Mechanisms of Staphylococcus epidermidis Strains Exposed to Increasing Concentrations of Didecyldimethylammonium Chloride. Microb Drug Resist 2020; 26:583-593. [PMID: 31910354 DOI: 10.1089/mdr.2019.0064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Staphylococcus epidermidis is a commensal inhabitant of human skin and mucosa, and a common nosocomial pathogen in immunocompromised patients. S. epidermidis strains were isolated from places with precisely defined and controlled air quality and regular cleaning and disinfection regimes-cleanrooms. These strains were adapted to increasing concentrations of the quaternary ammonium disinfectant didecyldimethylammonium chloride (DDAC). Compared to nonadapted strains, these strains became adapted to up to 180-fold higher concentrations of DDAC, as seen by their increased minimal inhibitory concentrations. Examination of the stability of adaptation showed that three strains became permanently adapted to DDAC and named as resistant strains, and four strains were temporarily adapted to DDAC and named as strains with higher tolerance to DDAC. Some adapted strains showed cross-resistance to benzalkonium chloride and/or antibiotics. The adaptation response mechanisms of these DDAC-adapted strains were also investigated. The majority of adapted strains showed modifications to cell size and fatty acid composition. Some of the adapted strains showed changes in biofilm formation and overexpression of efflux pumps. Three adapted strains also showed altered growth rates. In this first report of adaptation of S. epidermidis strains to DDAC, the fatty acid profiling showed that the majority of strains had reduced ratio of saturated to unsaturated fatty acids and decreased content of straight-chain fatty acids, at the expense of the anteiso-branched fatty acids. We can conclude that S. epidermidis strains can adapt or become resistant to DDAC. We have revealed several adaptive response mechanisms that can be targeted for control and inhibition of S. epidermidis in cleanrooms and other clean processing environments.
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Affiliation(s)
- Urška Ribič
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Tomaž Polak
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Mateja Lušnic Polak
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Anja Klančnik
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Barbara Jeršek
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
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7
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Multidrug ABC transporters in bacteria. Res Microbiol 2019; 170:381-391. [DOI: 10.1016/j.resmic.2019.06.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 06/12/2019] [Accepted: 06/17/2019] [Indexed: 12/23/2022]
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8
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Sinha S, Gupta VK, Kumar P, Kumar R, Joshi R, Pal A, Darokar MP. Usnic acid modifies MRSA drug resistance through down-regulation of proteins involved in peptidoglycan and fatty acid biosynthesis. FEBS Open Bio 2019; 9:2025-2040. [PMID: 31050202 PMCID: PMC6886298 DOI: 10.1002/2211-5463.12650] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 03/10/2019] [Accepted: 05/01/2019] [Indexed: 01/17/2023] Open
Abstract
Multidrug‐resistant Staphylococcus aureus infections place a huge burden on the healthcare sector and the wider community. An increasing rate of infections caused by methicillin‐resistant Staphylococcus aureus (MRSA) has necessitated the development of alternative agents. We previously reported that usnic acid (UA) has activity against MRSA; here, we report the effect of UA in combination with norfloxacin on the drug resistance of MRSA clinical isolates. We observed that the combination of UA–norfloxacin significantly reduces the bacterial burden in mouse models infected with S. aureus, without causing any detectable associated toxicity. Proteomic analysis indicated that UA–norfloxacin induces oxidative stress within cells, which leads to membrane damage and inhibits metabolic activity and biosynthesis of peptidoglycan and fatty acids. Collectively, this study provides evidence that UA in combination with norfloxacin may be a potential candidate for development into a resistance‐modifying agent for the treatment of invasive MRSA infections. This is the first report on the drug resistance‐modifying potential of usnic acid (UA) through inhibition of the multidrug resistance (MDR) efflux pump and down‐regulation of proteins involved in peptidoglycan and fatty acid biosynthesis. This compound may be helpful in the management of infection caused by MRSA through (a) lowering the prescribed amount of antibiotics, (b) decreasing MDR generation, and (c) intensifying the efficacy of antibiotics against MRSA/VRSA under both in vitro and in vivo conditions. These results may be helpful in the development of anti‐MRSA drug combinations from economical and non‐toxic natural products.![]()
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Affiliation(s)
- Sneha Sinha
- Molecular Bioprospection Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Vivek Kumar Gupta
- Molecular Bioprospection Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Parmanand Kumar
- Molecular Bioprospection Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Rajiv Kumar
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, India
| | - Robin Joshi
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, India
| | - Anirban Pal
- Molecular Bioprospection Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Mahendra P Darokar
- Molecular Bioprospection Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
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9
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Abd El-Baky RM, Sandle T, John J, Abuo-Rahma GEDA, Hetta HF. A novel mechanism of action of ketoconazole: inhibition of the NorA efflux pump system and biofilm formation in multidrug-resistant Staphylococcus aureus. Infect Drug Resist 2019; 12:1703-1718. [PMID: 31354319 PMCID: PMC6585162 DOI: 10.2147/idr.s201124] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 03/11/2019] [Indexed: 11/23/2022] Open
Abstract
Background: The rapid emergence of antimicrobial resistance among Gram-positive organisms, especially staphylococci, has become a serious clinical challenge. Efflux machinery and biofilm formation are considered two of the main causes of antimicrobial resistance and therapy failure. Aim: Our study aims to evaluate the antibiofilm and efflux pump inhibitory activity of the antifungal ketoconazole against multidrug-resistant (MDR) Staphylococcus aureus. Methods: Ketoconazole was tested for its effect on the following: minimum inhibitory concentrations (MICs) of ciprofloxacin, norfloxacin, levofloxacin, and ethidium bromide (EtBr) by the broth microdilution method, the efflux of EtBr by NorA-positive MDR S. aureus, and the relative expression of NorA, NorB, and NorC efflux pump genes. Docking studies of ketoconazole were performed using 1PW4 (glycerol-3-phosphate transporter from Escherichia coli which was the representative structure from the major facilitator superfamily). Results: Ketoconazole significantly decreased the MICs of levofloxacin, ciprofloxacin, norfloxacin, and EtBr (a substrate for efflux pump) by 8 to 1024-fold (P<0.01) and decreased the efflux of EtBr. Furthermore, a time-kill assay revealed that combinations of levofloxacin with ketoconazole or carbonyl cyanide m-chlorophenylhydrazone showed no growth for the tested strains after 24 h in comparison to the effect of levofloxacin alone. Docking studies and the ability of ketoconazole to diminish the relative expression of NorA gene in comparison to control (untreated strains) confirmed its action as an efflux pump inhibitor. Conclusion: The findings showed that the antifungal ketoconazole has no antibacterial activity but can potentiate the activity of the fluroquinolones against MDR S. aureus via inhibiting efflux pump and biofilm formation in vitro.
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Affiliation(s)
- Rehab M Abd El-Baky
- Department of Microbiology and Immunology, Faculty of Pharmacy, Minia University, Minia 61519, Egypt.,Microbiology and Immunology Department, Faculty of Pharmacy, Deraya University, Minia 11566, Egypt
| | - Tim Sandle
- School of Health Sciences, Division of Pharmacy & Optometry, University of Manchester, Manchester, UK
| | - James John
- Sri Ramachandra Medical College and Research Institute, Sri Ramachandra University, Chennai, India
| | | | - Helal F Hetta
- Department of Medical Microbiology & Immunology, Faculty of Medicine, Assiut University, Assiut, Egypt.,Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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10
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The role played by drug efflux pumps in bacterial multidrug resistance. Essays Biochem 2017; 61:127-139. [DOI: 10.1042/ebc20160064] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 01/22/2017] [Accepted: 01/24/2017] [Indexed: 01/19/2023]
Abstract
Antimicrobial resistance is a current major challenge in chemotherapy and infection control. The ability of bacterial and eukaryotic cells to recognize and pump toxic compounds from within the cell to the environment before they reach their targets is one of the important mechanisms contributing to this phenomenon. Drug efflux pumps are membrane transport proteins that require energy to export substrates and can be selective for a specific drug or poly-specific that can export multiple structurally diverse drug compounds. These proteins can be classified into seven groups based on protein sequence homology, energy source and overall structure. Extensive studies on efflux proteins have resulted in a wealth of knowledge that has made possible in-depth understanding of the structures and mechanisms of action, substrate profiles, regulation and possible inhibition of many clinically important efflux pumps. This review focuses on describing known families of drug efflux pumps using examples that are well characterized structurally and/or biochemically.
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11
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Schroeder M, Brooks BD, Brooks AE. The Complex Relationship between Virulence and Antibiotic Resistance. Genes (Basel) 2017; 8:E39. [PMID: 28106797 PMCID: PMC5295033 DOI: 10.3390/genes8010039] [Citation(s) in RCA: 155] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 12/21/2016] [Accepted: 01/07/2017] [Indexed: 12/17/2022] Open
Abstract
Antibiotic resistance, prompted by the overuse of antimicrobial agents, may arise from a variety of mechanisms, particularly horizontal gene transfer of virulence and antibiotic resistance genes, which is often facilitated by biofilm formation. The importance of phenotypic changes seen in a biofilm, which lead to genotypic alterations, cannot be overstated. Irrespective of if the biofilm is single microbe or polymicrobial, bacteria, protected within a biofilm from the external environment, communicate through signal transduction pathways (e.g., quorum sensing or two-component systems), leading to global changes in gene expression, enhancing virulence, and expediting the acquisition of antibiotic resistance. Thus, one must examine a genetic change in virulence and resistance not only in the context of the biofilm but also as inextricably linked pathologies. Observationally, it is clear that increased virulence and the advent of antibiotic resistance often arise almost simultaneously; however, their genetic connection has been relatively ignored. Although the complexities of genetic regulation in a multispecies community may obscure a causative relationship, uncovering key genetic interactions between virulence and resistance in biofilm bacteria is essential to identifying new druggable targets, ultimately providing a drug discovery and development pathway to improve treatment options for chronic and recurring infection.
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Affiliation(s)
- Meredith Schroeder
- Department of Microbiological Sciences; North Dakota State University, Fargo, ND 58105, USA.
| | - Benjamin D Brooks
- Department of Electrical and Computer Engineering; North Dakota State University, Fargo, ND 58105, USA.
| | - Amanda E Brooks
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND 58105, USA.
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12
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Bhaskar BV, Babu TMC, Reddy NV, Rajendra W. Homology modeling, molecular dynamics, and virtual screening of NorA efflux pump inhibitors of Staphylococcus aureus. DRUG DESIGN DEVELOPMENT AND THERAPY 2016; 10:3237-3252. [PMID: 27757014 PMCID: PMC5055111 DOI: 10.2147/dddt.s113556] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Emerging drug resistance in clinical isolates of Staphylococcus aureus might be implicated to the overexpression of NorA efflux pump which is capable of extruding numerous structurally diverse compounds. However, NorA efflux pump is considered as a potential drug target for the development of efflux pump inhibitors. In the present study, NorA model was constructed based on the crystal structure of glycerol-3-phosphate transporter (PDBID: 1PW4). Molecular dynamics (MD) simulation was performed using NAMD2.7 for NorA which is embedded in the hydrated lipid bilayer. Structural design of NorA unveils amino (N)- and carboxyl (C)-terminal domains which are connected by long cytoplasmic loop. N and C domains are composed of six transmembrane α-helices (TM) which exhibits pseudo-twofold symmetry and possess voluminous substrate binding cavity between TM helices. Molecular docking of reserpine, totarol, ferruginol, salvin, thioxanthene, phenothiazine, omeprazole, verapamil, nalidixic acid, ciprofloxacin, levofloxacin, and acridine to NorA found that all the molecules were bound at the large hydrophobic cleft and indicated significant interactions with the key residues. In addition, structure-based virtual screening was employed which indicates that 14 potent novel lead molecules such as CID58685302, CID58685367, CID5799283, CID5578487, CID60028372, ZINC12196383, ZINC72140751, ZINC72137843, ZINC39227983, ZINC43742707, ZINC12196375, ZINC66166948, ZINC39228014, and ZINC14616160 have highest binding affinity for NorA. These lead molecules displayed considerable pharmacological properties as evidenced by Lipinski rule of five and prophecy of toxicity risk assessment. Thus, the present study will be helpful in designing and synthesis of a novel class of NorA efflux pump inhibitors that restore the susceptibilities of drug compounds.
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Affiliation(s)
| | | | - Netala Vasudeva Reddy
- Department of Biotechnology, Sri Venkateswara University, Tirupati, Andhra Pradesh, India
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13
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Schindler BD, Kaatz GW. Multidrug efflux pumps of Gram-positive bacteria. Drug Resist Updat 2016; 27:1-13. [DOI: 10.1016/j.drup.2016.04.003] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 03/28/2016] [Accepted: 04/22/2016] [Indexed: 11/16/2022]
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14
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Mutations within the mepA operator affect binding of the MepR regulatory protein and its induction by MepA substrates in Staphylococcus aureus. J Bacteriol 2015; 197:1104-14. [PMID: 25583977 DOI: 10.1128/jb.02558-14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The expression of mepA, encoding the Staphylococcus aureus MepA multidrug efflux protein, is repressed by the MarR homologue MepR. Repression occurs through binding of two MepR dimers to an operator with two homologous and closely approximated pseudopalindromic binding sites (site 1 [S1] and site 2 [S2]). MepR binding is impeded in the presence of pentamidine, a MepA substrate. The effects of various mepA operator mutations on MepR binding were determined using electrophoretic mobility shift assays and isothermal titration calorimetry, and an in vivo confirmation of the effects observed was established for a fully palindromic operator mutant. Altering the S1-S2 spacing by 1 to 4 bp severely impaired S2 binding, likely due to a physical collision between adjacent MepR dimers. Extension of the spacing to 9 bp eliminated the S1 binding-mediated DNA allostery required for efficient S2 binding, consistent with positive cooperative binding of MepR dimers. Binding of a single dimer to S1 was maintained when S2 was disrupted, whereas disruption of S1 eliminated any significant binding to S2, also consistent with positive cooperativity. Palindromization of binding sites, especially S2, enhanced MepR affinity for the mepA operator and reduced MepA substrate-mediated MepR induction. As a result, the on-off equilibrium between MepR and its binding sites was shifted toward the on state, resulting in less free MepR being available for interaction with inducing ligand. The selective pressure(s) under which mepA expression is advantageous likely contributed to the accumulation of mutations in the mepA operator, resulting in the current sequence from which MepR is readily induced by MepA substrates.
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Schindler BD, Jacinto PL, Buensalido JAL, Seo SM, Kaatz GW. Clonal relatedness is a predictor of spontaneous multidrug efflux pump gene overexpression in Staphylococcus aureus. Int J Antimicrob Agents 2014; 45:464-70. [PMID: 25548027 DOI: 10.1016/j.ijantimicag.2014.11.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 09/22/2014] [Accepted: 11/07/2014] [Indexed: 10/24/2022]
Abstract
Increased expression of genes encoding multidrug resistance efflux pumps (MDR-EPs) contributes to antimicrobial agent and biocide resistance in Staphylococcus aureus. Previously identified associations between norA overexpression and spa type t002 meticillin-resistant S. aureus (MRSA), and a similar yet weaker association between mepA overexpression and type t008 meticillin-susceptible S. aureus (MSSA), in clinical isolates are suggestive of clonal dissemination. It is also possible that related strains are prone to mutations resulting in overexpression of specific MDR-EP genes. Exposure of non-MDR-EP-overexpressing clinical isolates to biocides and dyes can select for MDR-EP-overexpressing mutants. spa types t002 and t008 isolates are predominated by multilocus sequencing typing sequence types (STs) 5 and 8, respectively. In this study, non-MDR-EP gene-overexpressing clinical isolates (MRSA and MSSA) representing ST5 and ST8 were subjected to single exposures of ethidium bromide (EtBr) to select for EtBr-resistant mutants. Measurements of active EtBr transport among mutants were used to demonstrate an efflux-proficient phenotype. Using quantitative reverse-transcription PCR, it was found that EtBr-resistant mutants of ST5 and ST8 parental strains predominantly overexpressed mepA (100%) and mdeA (83%), respectively, regardless of meticillin sensitivity. Associations between clonal lineage and MDR-EP gene overexpression differed from those previously observed and suggest the latter is due to clonal spread of efflux-proficient strains. The predilection of in vitro-selected mutants of related strains to overexpress the same MDR-EP gene indicates the presence of a consistent mutational process.
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Affiliation(s)
- Bryan D Schindler
- The John D. Dingell Department of Veterans Affairs Medical Center, Detroit, MI 48201, USA
| | - Pauline L Jacinto
- Department of Internal Medicine, Division of Infectious Diseases, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Joseph Adrian L Buensalido
- Department of Internal Medicine, Division of Infectious Diseases, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Susan M Seo
- The John D. Dingell Department of Veterans Affairs Medical Center, Detroit, MI 48201, USA
| | - Glenn W Kaatz
- The John D. Dingell Department of Veterans Affairs Medical Center, Detroit, MI 48201, USA; Department of Internal Medicine, Division of Infectious Diseases, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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Hequet A, Burchak ON, Jeanty M, Guinchard X, Le Pihive E, Maigre L, Bouhours P, Schneider D, Maurin M, Paris JM, Denis JN, Jolivalt C. 1-(1H-Indol-3-yl)ethanamine Derivatives as PotentStaphylococcus aureusNorA Efflux Pump Inhibitors. ChemMedChem 2014; 9:1534-45. [DOI: 10.1002/cmdc.201400042] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Indexed: 11/11/2022]
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Effects of Chlorophyll-Derived Efflux Pump Inhibitor Pheophorbide a and Pyropheophorbide a on Growth and Macrolide Antibiotic Resistance of Indicator and Anaerobic Swine Manure Bacteria. ACTA ACUST UNITED AC 2014. [DOI: 10.1155/2014/185068] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Natural plant compounds, such as the chlorophyll a catabolites pheophorbide a (php) and pyropheophorbide a (pyp), are potentially active in the gastrointestinal tracts and manure of livestock as antimicrobial resistance-modifying agents through inhibition of bacterial efflux pumps. To investigate whether php, a known efflux pump inhibitor, and pyp influence bacterial resistance, we determined their long-term effects on the MICs of erythromycin for reference strains of clinically relevant indicator bacteria with macrolide or multidrug resistance efflux pumps. Pyp reduced the final MIC endpoint for Staphylococcus (S.) aureus and Escherichia (E.) coli by up to 1536 and 1024 μg erythromycin mL−1 or 1.4- and 1.2-fold, respectively. Estimation of growth parameters of S. aureus revealed that pyp exerted an intrinsic inhibitory effect under anaerobic conditions and was synergistically active, thereby potentiating the effect of erythromycin and partially reversing high-level erythromycin resistance. Anaerobe colony counts of total and erythromycin-resistant bacteria from stored swine manure samples tended to be lower in the presence of pyp. Tylosin, php, and pyp were not detectable by HPLC in the manure or medium. This is the first study showing that pyp affects growth and the level of sensitivity to erythromycin of S. aureus, E. coli, and anaerobic manure bacteria.
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Modulation of Bacterial Multidrug Resistance Efflux Pumps of the Major Facilitator Superfamily. INTERNATIONAL JOURNAL OF BACTERIOLOGY 2013; 2013. [PMID: 25750934 PMCID: PMC4347946 DOI: 10.1155/2013/204141] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bacterial infections pose a serious public health concern, especially when an infectious disease has a multidrug resistant causative agent. Such multidrug resistant bacteria can compromise the clinical utility of major chemotherapeutic antimicrobial agents. Drug and multidrug resistant bacteria harbor several distinct molecular mechanisms for resistance. Bacterial antimicrobial agent efflux pumps represent a major mechanism of clinical resistance. The major facilitator superfamily (MFS) is one of the largest groups of solute transporters to date and includes a significant number of bacterial drug and multidrug efflux pumps. We review recent work on the modulation of multidrug efflux pumps, paying special attention to those transporters belonging primarily to the MFS.
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Vandendriessche S, Vanderhaeghen W, Larsen J, de Mendonça R, Hallin M, Butaye P, Hermans K, Haesebrouck F, Denis O. High genetic diversity of methicillin-susceptible Staphylococcus aureus (MSSA) from humans and animals on livestock farms and presence of SCCmec remnant DNA in MSSA CC398. J Antimicrob Chemother 2013; 69:355-62. [PMID: 24072172 DOI: 10.1093/jac/dkt366] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
OBJECTIVES To investigate the genetic diversity of methicillin-susceptible Staphylococcus aureus (MSSA) carriage isolates from animals and humans on pig, veal, dairy, beef and broiler farms. METHODS S. aureus isolates were genotyped using spa typing and multilocus sequence typing (MLST). Antimicrobial susceptibility phenotypes and genotypes were determined. The presence of staphylococcal cassette chromosome mec (SCCmec)-associated DNA was characterized by PCR and sequencing among isolates of clonal complex (CC) 398. RESULTS Overall, 41 MSSA isolates in humans and 141 in animals were found, originating from all farm types. These MSSA were mainly assigned to CC398, CC1, CC5, CC9, CC30, CC97, CC133 and CC705/151. MSSA CC398 showed resistance to tetracycline, trimethoprim, macrolides and/or lincosamides, aminoglycosides, ciprofloxacin, spectinomycin and quinupristin/dalfopristin, whereas non-CC398 MSSA showed considerably less resistance. Three porcine MSSA CC398-t011 isolates harboured remnant DNA of a composite SCCmec V(5C2&5)c element that lacked the mec gene complex. This resulted from an MRSA-to-MSSA conversion due to recombination between the ccrC genes flanking the mec gene complex. The SCC remnant still contained an intact J1 region harbouring czrC and tet(K), encoding zinc and tetracycline resistance, respectively, thereby illustrating the capacity of S. aureus CC398 to adapt to different antibiotic selection pressures in the farming environment. Processes such as mec gene complex deletion probably contribute to the enormous diversity of SCC(mec) elements observed in staphylococci. CONCLUSIONS MSSA CC398 precursors from which MRSA CC398 might (re)emerge were present on pig, veal and broiler farms, all of which are livestock sectors commonly known to be affected by MRSA CC398. The multiresistance phenotype of S. aureus CC398 appears to be independent of methicillin resistance.
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Affiliation(s)
- Stien Vandendriessche
- National Reference Centre for S. aureus, Department of Microbiology, Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium
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Schindler BD, Jacinto P, Kaatz GW. Inhibition of drug efflux pumps in Staphylococcus aureus: current status of potentiating existing antibiotics. Future Microbiol 2013; 8:491-507. [PMID: 23534361 DOI: 10.2217/fmb.13.16] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The emergence of multidrug-resistant Staphylococcus aureus coupled with a declining output of new antibiotic treatment options from the pharmaceutical industry is a growing worldwide healthcare problem. Multidrug efflux pumps are known to play a role in antibiotic and biocide resistance in S. aureus. These membrane transporters are capable of extruding drugs and other structurally unrelated compounds, hence decreasing intracellular concentration and increasing survival. Coadministration of efflux pump inhibitors (EPIs) with antibiotics that are pump substrates could increase intracellular drug levels, thus bringing renewed efficacy to existing antistaphylococcal agents. Numerous EPIs have been identified or synthesized over the past two decades; these include existing pharmacologic drugs, naturally occurring compounds, and synthetic derivatives thereof. This review describes the current progress in EPI development for use against S. aureus.
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Affiliation(s)
- Bryan D Schindler
- John D Dingell Veterans Affairs Medical Center, Wayne State University, Detroit, MI 48201, USA
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Expression of multidrug resistance efflux pump genes in clinical and environmental isolates of Staphylococcus aureus. Int J Antimicrob Agents 2012; 40:204-9. [DOI: 10.1016/j.ijantimicag.2012.04.014] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 04/14/2012] [Accepted: 04/16/2012] [Indexed: 11/21/2022]
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França CA, Peixoto RM, Cavalcante MB, Melo NF, Oliveira CJB, Veschi JLA, Mota RA, Costa MM. Antimicrobial resistance of Staphylococcus spp. from small ruminant mastitis in Brazil. PESQUISA VETERINARIA BRASILEIRA 2012. [DOI: 10.1590/s0100-736x2012000800012] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The study aimed to determine the antimicrobial resistance patterns and to identify molecular resistance markers in Staphylococcus spp. (n=210) isolated from small ruminant mastitis in Brazil. The antimicrobial resistance patterns were evaluated by the disk diffusion test and by detection of the presence of mecA, blaZ, ermA, ermB, ermC and msrA genes by PCR. The efflux pump test was performed using ethidium bromide and biofilm production was determined by Congo red agar test along with PCR for detection of the icaD gene. The isolates were most resistant to amoxicillin (50.0%), streptomycin (42.8%), tetracycline (40.4%), lincomycin (39.0%) and erythromycin (33.8%). Pan-susceptibility to all tested drugs was observed in 71 (33.8%) isolates and 41 Staphylococcus isolates were positive for the efflux pump. Although phenotypic resistance to oxacillin was observed in 12.8% of the isolates, none harbored the mecA gene. However, 45.7% of the isolates harbored blaZ indicating that beta-lactamase production was the main mechanism associated with staphylococci resistance to beta-lactams in the present study. The other determinants of resistance to antimicrobial agents ermA, ermB, ermC, and msrA were observed in 1.4%, 10.4%, 16.2%, and 0.9% of the isolates, respectively. In addition, the icaD gen was detected in 32.9% of the isolates. Seventy three isolates (54 from goats and 19 from sheep) were negative for all resistance genes tested and 69 isolates presented two or more resistance genes. Association among blaZ, ermA, ermB, ermC and efflux pump were observed in 17 isolates, 14 of which originated from goats and three from sheep. The data obtained in this study show the resistance of the isolates to beta-lactamics, which may be associated with the use of antimicrobial drugs without veterinary control.
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Affiliation(s)
| | - Rodolfo M. Peixoto
- Instituto Federal de Educação, Ciência e Tecnologia do Sertão Pernambucano, Brazil
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Holler JG, Slotved HC, Mølgaard P, Olsen CE, Christensen SB. Chalcone inhibitors of the NorA efflux pump in Staphylococcus aureus whole cells and enriched everted membrane vesicles. Bioorg Med Chem 2012; 20:4514-21. [PMID: 22682300 DOI: 10.1016/j.bmc.2012.05.025] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 05/01/2012] [Accepted: 05/11/2012] [Indexed: 11/19/2022]
Abstract
A library of 117 chalcones was screened for efflux pump inhibitory (EPI) activity against NorA mediated ethidium bromide efflux. Five of the chalcones (5-7, 9, and 10) were active and two chalcones (9 and 10) were equipotent to reserpine with IC(50)-values of 9.0 and 7.7 μM, respectively. Twenty chalcones were subsequently proved to be inhibitors of the NorA efflux pump in everted membrane vesicles. Compounds 5, 7, and 9 synergistically increased the effect of ciprofloxacin on Staphylococcus aureus. Our results suggest that chalcones might be developed into drugs for overcoming multidrug resistance based on efflux transporters of microorganisms.
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Affiliation(s)
- Jes Gitz Holler
- University of Copenhagen, Faculty of Pharmaceutical Sciences, Department of Medicinal Chemistry, Denmark.
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Biochemistry of bacterial multidrug efflux pumps. Int J Mol Sci 2012; 13:4484-4495. [PMID: 22605991 PMCID: PMC3344227 DOI: 10.3390/ijms13044484] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 03/09/2012] [Accepted: 03/15/2012] [Indexed: 11/17/2022] Open
Abstract
Bacterial pathogens that are multi-drug resistant compromise the effectiveness of treatment when they are the causative agents of infectious disease. These multi-drug resistance mechanisms allow bacteria to survive in the presence of clinically useful antimicrobial agents, thus reducing the efficacy of chemotherapy towards infectious disease. Importantly, active multi-drug efflux is a major mechanism for bacterial pathogen drug resistance. Therefore, because of their overwhelming presence in bacterial pathogens, these active multi-drug efflux mechanisms remain a major area of intense study, so that ultimately measures may be discovered to inhibit these active multi-drug efflux pumps.
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Muthukrishnan G, Quinn GA, Lamers RP, Diaz C, Cole AL, Chen S, Cole AM. Exoproteome of Staphylococcus aureus reveals putative determinants of nasal carriage. J Proteome Res 2011; 10:2064-78. [PMID: 21338050 DOI: 10.1021/pr200029r] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Due to the increasing prevalence of nosocomial and community-acquired antibiotic resistant Staphylococcus aureus (SA), understanding the determinants of SA nasal carriage has become a major imperative. Previous research has revealed many host and bacterial factors that contribute to SA nasal carriage. To assess bacterial factors that facilitate nasal carriage, we compared the exoproteome of a nasal carrier strain of SA to a genetically similar noncarrier strain. Additionally, the carrier strain biofilm exoproteome was also compared against its planktonic counterpart. Using high throughput proteomics, it was observed that the carrier strain of SA secretes a greater number of proteins that may promote successful colonization of the human nose, including cell attachment and immunoevasive proteins, than the noncarrier strain. Similarly, SA carrier strain biofilm exoproteome contains a greater number of immunoevasive proteins than its planktonic counterpart. Analysis of the most abundant immunoevasive proteins revealed that Staphylococcal protein A was present at significantly higher levels in carrier than in noncarrier strains of SA, suggesting an association with nasal carriage. While further analyses of specific differences between carrier and noncarrier strains of SA are required, many of the differentially expressed proteins identified can be considered to be putative determinants of nasal carriage.
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Affiliation(s)
- Gowrishankar Muthukrishnan
- Laboratory of Innate Host Defense, Department of Molecular Biology and Microbiology, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, United States
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Mode-of-action studies of the novel bisquaternary bisnaphthalimide MT02 against Staphylococcus aureus. Antimicrob Agents Chemother 2010; 55:311-20. [PMID: 20937782 DOI: 10.1128/aac.00586-10] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Screening of various bisquaternary bisnaphthalimides against a variety of human pathogens revealed one compound, designated MT02, with strong inhibitory effects against Gram-positive bacteria. The MICs ranged from 0.31 μg/ml against community-acquired methicillin-resistant Staphylococcus aureus (MRSA) lineage USA300 to 20 μg/ml against Streptococcus pneumoniae. Radioactive whole-cell labeling experiments indicated a strong impact of MT02 on bacterial DNA replication. DNA microarray studies generated a transcriptional signature characterized by stronger expression of genes involved in DNA metabolism, DNA replication, SOS response, and transport of positively charged compounds. Furthermore, surface plasmon resonance and gel retardation experiments demonstrated direct binding of MT02 to DNA in a concentration-dependent, reversible, and non-sequence-specific manner. The data presented suggest that the bisquaternary bisnaphthalimide MT02 exerts anti-Gram-positive activity by binding to DNA and thereby preventing appropriate DNA replication.
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Ethidium bromide MIC screening for enhanced efflux pump gene expression or efflux activity in Staphylococcus aureus. Antimicrob Agents Chemother 2010; 54:5070-3. [PMID: 20855743 DOI: 10.1128/aac.01058-10] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Multidrug resistance efflux pumps contribute to antimicrobial and biocide resistance in Staphylococcus aureus. The detection of strains capable of efflux is time-consuming and labor-intensive using currently available techniques. A simple and inexpensive method to identify such strains is needed. Ethidium bromide is a substrate for all but one of the characterized S. aureus multidrug-resistant (MDR) efflux pumps (NorC), leading us to examine the utility of simple broth microtiter MIC determinations using this compound in identifying efflux-proficient strains. Quantitative reverse transcription-PCR identified the increased expression of one or more MDR efflux pump genes in 151/309 clinical strains (49%). Ethidium bromide MIC testing was insensitive (48%) but specific (92%) in identifying strains with gene overexpression, but it was highly sensitive (95%) and specific (99%) in identifying strains capable of ethidium efflux. The increased expression of norA with or without other genes was most commonly associated with efflux, and in the majority of cases that efflux was inhibited by reserpine. Ethidium bromide MIC testing is a simple and straightforward method to identify effluxing strains and can provide accurate predictions of efflux prevalence in large strain sets in a short period of time.
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Kosmidis C, DeMarco CE, Frempong-Manso E, Seo SM, Kaatz GW. In silico genetic correlations of multidrug efflux pump gene expression in Staphylococcus aureus. Int J Antimicrob Agents 2010; 36:222-9. [PMID: 20598861 DOI: 10.1016/j.ijantimicag.2010.05.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 05/27/2010] [Accepted: 05/28/2010] [Indexed: 10/19/2022]
Abstract
Regulatory mechanisms for chromosomal genes encoding multidrug resistance (MDR) efflux pumps (EPs) in Staphylococcus aureus are poorly defined. Microbiological, quantitative gene expression, mRNA half-life and genome data for 11 strains of S. aureus combined with bioinformatic analyses were used to identify correlates of increased MDR EP gene expression. The presence of qacA/B and/or increased expression of one to two MDR EP genes were identified in eight strains. Microbiological and gene expression data correlated in four instances, existing knowledge of the substrate specificity of NorC resulted in correlation in two others, and a transcriptional/translational disconnect is possible for the remaining two. In silico analyses and mRNA half-life determinations linked insertions of nucleotide repeats 3' to the -10 motif of the norA promoter with increased promoter activity. Mutations in the 5'-untranslated and/or coding regions were identified that may affect transcription efficiency. Substitutions of residues in the helix-turn-helix (HTH) motif of NorG may augment its positive regulation of norB. The correlations proposed provide a guide for further experimentation leading to a better understanding of MDR EP gene expression in this important pathogen.
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Affiliation(s)
- Christos Kosmidis
- Department of Medicine, Division of Infectious Diseases, Wayne State University School of Medicine, Detroit, MI 48201, USA
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Bornstein E, Gridley S, Wengender P, Robbins A. Photodamage to multidrug-resistant gram-positive and gram-negative bacteria by 870 nm/930 nm light potentiates erythromycin, tetracycline and ciprofloxacin. Photochem Photobiol 2010; 86:617-27. [PMID: 20408973 DOI: 10.1111/j.1751-1097.2010.00725.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We have previously shown that 870 nm/930 nm wavelengths cause photodamage at physiologic temperatures in methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli via generation of endogenous radical oxygen species (ROS) and decreased plasma membrane potentials (Delta Psi p). We tested MRSA (Strain HSJ216) in vitro with sublethal 870 nm/930 nm laser energy and subinhibitory concentrations of erythromycin, tetracycline, penicillin, rifampin and trimethoprim to surmise whether photodamage could potentiate these antimicrobials. We also tested patient isolates of fluoroquinolone-resistant MRSA and E. coli with subinhibitory concentrations of ciprofloxacin. In MRSA (Strain HSJ216) we observed 97% potentiation (a 1.5 log(10) CFU decrease) with erythromycin and tetracycline. In patient isolates of E. coli, we observed 100% potentiation (>3 log(10) CFU decrease) in all irradiated samples with ciprofloxacin. To assess whether staphyloxanthin pigment conferred protection against the generated ROS, we created an isogenic carotenoid-deficient mutant of S. aureus that was significantly less tolerant of 870 nm/930 nm exposure than the wild type strain (P < 0.0001). We suggest that antibiotic potentiation results from a photobiological attenuation of ATP-dependent macromolecular synthetic pathways, similar to that observed with daptomycin, via disruption of Delta Psi p and endogenous generation of ROS. With erythromycin, tetracycline and ciprofloxacin, attenuation of energy-dependent efflux systems is also a possibility.
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Lomovskaya O, Zgurskaya HI, Bostian K. Bacterial Multidrug Transporters: Molecular and Clinical Aspects. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/9783527627424.ch5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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McCallum N, Berger-Bächi B, Senn MM. Regulation of antibiotic resistance in Staphylococcus aureus. Int J Med Microbiol 2009; 300:118-29. [PMID: 19800843 DOI: 10.1016/j.ijmm.2009.08.015] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Staphylococcus aureus has a formidable ability to adapt to varying environmental conditions and an extraordinary capacity to rapidly become resistant to virtually all antibiotics. Resistance develops either through mutations and rearrangements within the staphylococcal genome, or by the acquisition of resistance determinants. Antibiotic resistances often impose a fitness burden on the host. Such biological costs can be reduced by tight regulation and antibiotic-inducible expression of resistance genes, or by compensatory mutations. Resistance induction by antibiotics can be mediated by dedicated, antibiotic-recognizing signal transducers or by mechanisms relieving translational attenuation. Antibiotic tolerance and the expression of resistance phenotypes can also be strongly influenced by the genetic backgrounds of strains and several other factors. Modification and indirect regulation of resistance levels can occur by mutations that alter gene expression or substrate specificity of genes contributing to resistance. Insertion elements can alter resistance profiles by turning relevant genes on or off. Environmental conditions and stress response mechanisms triggered by perturbation of the cell envelope, DNA damage, or faulty intermediary metabolism can also have an impact on resistance development and expression. Clinically relevant resistance is often built up through multiple steps, each of which contributes to an increase in resistance. The driving force behind resistance formation is antibiotic stress, and under clinical conditions selection for resistance is continuously competing with selection for bacterial fitness.
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Affiliation(s)
- Nadine McCallum
- Institute of Medical Microbiology, University of Zürich, Gloriastrasse 32, CH-8006 Zürich, Switzerland
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Abstract
Drug efflux pumps play a key role in drug resistance and also serve other functions in bacteria. There has been a growing list of multidrug and drug-specific efflux pumps characterized from bacteria of human, animal, plant and environmental origins. These pumps are mostly encoded on the chromosome, although they can also be plasmid-encoded. A previous article in this journal provided a comprehensive review regarding efflux-mediated drug resistance in bacteria. In the past 5 years, significant progress has been achieved in further understanding of drug resistance-related efflux transporters and this review focuses on the latest studies in this field since 2003. This has been demonstrated in multiple aspects that include but are not limited to: further molecular and biochemical characterization of the known drug efflux pumps and identification of novel drug efflux pumps; structural elucidation of the transport mechanisms of drug transporters; regulatory mechanisms of drug efflux pumps; determining the role of the drug efflux pumps in other functions such as stress responses, virulence and cell communication; and development of efflux pump inhibitors. Overall, the multifaceted implications of drug efflux transporters warrant novel strategies to combat multidrug resistance in bacteria.
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Affiliation(s)
- Xian-Zhi Li
- Human Safety Division, Veterinary Drugs Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario K1A OK9, Canada
| | - Hiroshi Nikaido
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202, USA
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Optimized production and analysis of the staphylococcal multidrug efflux protein QacA. Protein Expr Purif 2009; 64:118-24. [DOI: 10.1016/j.pep.2008.11.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 11/19/2008] [Accepted: 11/22/2008] [Indexed: 11/21/2022]
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Frempong-Manso E, Raygada JL, DeMarco CE, Seo SM, Kaatz GW. Inability of a reserpine-based screen to identify strains overexpressing efflux pump genes in clinical isolates of Staphylococcus aureus. Int J Antimicrob Agents 2008; 33:360-3. [PMID: 19097759 DOI: 10.1016/j.ijantimicag.2008.10.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Revised: 10/14/2008] [Accepted: 10/16/2008] [Indexed: 11/18/2022]
Abstract
Overexpression of efflux pump genes conferring multidrug resistance (MDR) in Staphylococcus aureus results in reduced susceptibility to select biocides, dyes and fluoroquinolones. Reserpine is commonly used as an inhibitor of MDR efflux pumps and previous work from our laboratory using a reserpine-based screen to identify clinical isolates with an efflux phenotype revealed that nearly one-half overexpressed norA-B-C, mepA or mdeA. The accuracy of reserpine in predicting efflux pump gene overexpression in clinical strains was examined in detail. Bloodstream isolates of S. aureus previously classified as non-effluxing strains by the reserpine screen underwent gene expression analysis using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). The reserpine screen failed to identify many strains shown by qRT-PCR to overexpress one or more MDR efflux pump genes. Microdilution susceptibility testing with and without reserpine also failed to predict efflux pump activity. Although gene expression does not always correlate with protein translation, our results indicate that in clinical S. aureus isolates the use of reserpine to predict the contribution of efflux to reduced susceptibility is not dependable. All strains used in studies designed to assess MDR efflux pump gene expression in clinical isolates should be evaluated by a method independent of in vitro susceptibility testing.
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Affiliation(s)
- Emmanuel Frempong-Manso
- Department of Medicine, Division of Infectious Diseases, Wayne State University School of Medicine, Detroit, MI 48201, USA
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Huet AA, Raygada JL, Mendiratta K, Seo SM, Kaatz GW. Multidrug efflux pump overexpression in Staphylococcus aureus after single and multiple in vitro exposures to biocides and dyes. MICROBIOLOGY-SGM 2008; 154:3144-3153. [PMID: 18832320 DOI: 10.1099/mic.0.2008/021188-0] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Biocides and dyes are commonly employed in hospital and laboratory settings. Many of these agents are substrates for multiple-drug resistance (MDR)-conferring efflux pumps of both Gram-positive and Gram-negative organisms. Several such pumps have been identified in Staphylococcus aureus, and mutants overexpressing the NorA and MepA MDR pumps following exposure to fluoroquinolones have been identified. The effect of exposure to low concentrations of biocides and dyes on the expression of specific pump genes has not been evaluated. Using quantitative reverse-transcription PCR we found that exposure of clinical isolates to low concentrations of a variety of biocides and dyes in a single step, or to gradually increasing concentrations over several days, resulted in the appearance of mutants overexpressing mepA, mdeA, norA and norC, with mepA overexpression predominating. Overexpression was frequently associated with promoter-region or regulatory protein mutations. Mutants having significant increases in MICs of common pump substrates but no changes in expression of studied pump genes were also observed; in these cases changes in expression of as-yet-unidentified MDR pump genes may have occurred. Strains of S. aureus that exist in relatively protected environments and are repeatedly exposed to sublethal concentrations of biocides can develop efflux-related resistance to those agents, and acquisition of such strains poses a threat to patients treated with antimicrobial agents that are also substrates for those pumps, such as ciprofloxacin and moxifloxacin.
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Affiliation(s)
- Aurélie A Huet
- École Supérieure de Microbiologie et Sécurité Alimentaire de Brest, Université de Bretagne Occidentale, Technopôle Brest-Iroise, 29280 Plouzané, France.,John D. Dingell Department of Veterans Affairs Medical Center, Detroit, MI 48201, USA
| | - Jose L Raygada
- Department of Medicine, Division of Infectious Diseases, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Kabir Mendiratta
- John D. Dingell Department of Veterans Affairs Medical Center, Detroit, MI 48201, USA
| | - Susan M Seo
- Department of Medicine, Division of Infectious Diseases, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Glenn W Kaatz
- Department of Medicine, Division of Infectious Diseases, Wayne State University School of Medicine, Detroit, MI 48201, USA.,John D. Dingell Department of Veterans Affairs Medical Center, Detroit, MI 48201, USA
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Wu J, Hassan KA, Skurray RA, Brown MH. Functional analyses reveal an important role for tyrosine residues in the staphylococcal multidrug efflux protein QacA. BMC Microbiol 2008; 8:147. [PMID: 18793443 PMCID: PMC2553796 DOI: 10.1186/1471-2180-8-147] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Accepted: 09/16/2008] [Indexed: 11/21/2022] Open
Abstract
Background The staphylococcal QacA multidrug efflux protein confers resistance to an exceptional number of structurally unrelated antimicrobial compounds. Aromatic amino acid residues have been shown to be highly important for the transport function of several multidrug transporters and are intimately involved in multidrug binding. This study investigated the structural and functional importance of the seven tyrosine residues in QacA by examining the phenotypic effect of incorporating conservative (aromatic) and non-conservative (non-aromatic) substitutions for these residues. Results Determination of the resistance profiles and analysis of drug transport assays revealed that non-conservative substitutions for most tyrosine residues influenced the QacA drug recognition spectrum. However, an aromatic residue at three tyrosine positions, 63, 410 and 429, was of importance for QacA-mediated transport and resistance to the majority of substrates tested. Conclusion A tyrosine or phenylalanine residue at amino acid positions corresponding to 63 of QacA in related drug efflux proteins is found to be highly conserved. Therefore, an aromatic side chain at this position is likely to partake in a function common to these drug transporters, such as proton translocation or essential intramolecular contacts, whereas aromatic residues at the non-conserved 410 and 429 positions are expected to mediate a QacA-specific function, possibly forming or stabilising part of the QacA drug binding region.
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Affiliation(s)
- Jingqin Wu
- School of Biological Sciences, The University of Sydney, Sydney, New South Wales, 2006, Australia.
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Sabatini S, Kaatz GW, Rossolini GM, Brandini D, Fravolini A. From phenothiazine to 3-phenyl-1,4-benzothiazine derivatives as inhibitors of the Staphylococcus aureus NorA multidrug efflux pump. J Med Chem 2008; 51:4321-30. [PMID: 18578473 DOI: 10.1021/jm701623q] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Overexpression of efflux pumps is an important mechanism by which bacteria evade effects of substrate antimicrobial agents and inhibition of such pumps is a promising strategy to circumvent this resistance mechanism. NorA is a Staphylococcus aureus multidrug efflux pump, the activity of which confers decreased susceptibility to many structurally unrelated agents, including fluoroquinolones, resulting in a multidrug resistant (MDR) phenotype. In this work, a series of 1,4-benzothiazine derivatives were designed and synthesized as a minimized structural template of phenothiazine MDR efflux pump inhibitors (EPIs) in an effort to identify more potent S. aureus NorA EPIs. Almost all derivatives evaluated showed good activity in combination with ciprofloxacin against S. aureus ATCC 25923; some were capable of completely restoring ciprofloxacin activity in a norA-overexpressing strain (SA-K2378). Compounds 6k and 7j displayed good activity against SA-1199B, a strain that also overexpresses norA, in an ethidium bromide (EtBr) efflux inhibition assay.
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Affiliation(s)
- Stefano Sabatini
- Dipartimento di Chimica e Tecnologia del Farmaco, Universita di Perugia, 06123 Perugia, Italy
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Staphylococcus aureus HrtA is an ATPase required for protection against heme toxicity and prevention of a transcriptional heme stress response. J Bacteriol 2008; 190:3588-96. [PMID: 18326576 DOI: 10.1128/jb.01921-07] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
During systemic infection, Staphylococcus aureus acquires nutrient iron from heme, the cofactor of vertebrate myoglobin and hemoglobin. Upon exposure to heme, S. aureus up-regulates the expression of the heme-regulated transporter, HrtAB. Strains lacking hrtAB exhibit increased sensitivity to heme toxicity, and upon heme exposure they elaborate a secreted protein response that interferes with the recruitment of neutrophils to the site of infection. Taken together, these results have led to the suggestion that hrtAB encodes an efflux system responsible for relieving the toxic effects of accumulated heme. Here we extend these observations by demonstrating that HrtA is the ATPase component of the HrtAB transport system. We show that HrtA is an Mn(2+)/Mg(2+)-dependent ATPase that functions at an optimal pH of 7.5 and exhibits in vitro temperature dependence uncommon to ABC transporter ATPases. Furthermore, we identify conserved residues within HrtA that are required for in vitro ATPase activity and are essential for the functionality of HrtA in vivo. Finally, we show that heme induces an alteration in the gene expression pattern of S. aureus Delta hrtA, implying the presence of a novel transcriptional regulatory mechanism responsible for the previously described immunomodulatory characteristics of hrtA mutants exposed to heme.
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