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Abass S, Parveen R, Irfan M, Malik Z, Husain SA, Ahmad S. Mechanism of antibacterial phytoconstituents: an updated review. Arch Microbiol 2024; 206:325. [PMID: 38913205 DOI: 10.1007/s00203-024-04035-y] [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: 04/25/2024] [Accepted: 06/05/2024] [Indexed: 06/25/2024]
Abstract
The increase of multiple drug resistance bacteria significantly diminishes the effectiveness of antibiotic armory and subsequently exaggerates the level of therapeutic failure. Phytoconstituents are exceptional substitutes for resistance-modifying vehicles. The plants appear to be a deep well for the discovery of novel antibacterial compounds. This is owing to the numerous enticing characteristics of plants, they are easily accessible and inexpensive, extracts or chemicals derived from plants typically have significant levels of action against infections, and they rarely cause serious adverse effects. The enormous selection of phytochemicals offers very distinct chemical structures that may provide both novel mechanisms of antimicrobial activity and deliver us with different targets in the interior of the bacterial cell. They can directly affect bacteria or act together with the crucial events of pathogenicity, in this manner decreasing the aptitude of bacteria to create resistance. Abundant phytoconstituents demonstrate various mechanisms of action toward multi drug resistance bacteria. Overall, this comprehensive review will provide insights into the potential of phytoconstituents as alternative treatments for bacterial infections, particularly those caused by multi drug resistance strains. By examining the current state of research in this area, the review will shed light on potential future directions for the development of new antimicrobial therapies.
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Affiliation(s)
- Sageer Abass
- Department of Biotechnology, Jamia Millia Islamia, New Delhi, 110025, India
- Department of Biosciences, Jamia Millia Islamia, New Delhi, 110025, India
- Centre of Excellence in Unani Medicine (Pharmacognosy and Pharmacology), Bioactive Natural Product Laboratory, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi, 110062, India
| | - Rabea Parveen
- Centre of Excellence in Unani Medicine (Pharmacognosy and Pharmacology), Bioactive Natural Product Laboratory, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi, 110062, India
| | - Mohammad Irfan
- Department of Biotechnology, Jamia Millia Islamia, New Delhi, 110025, India
- Department of Biosciences, Jamia Millia Islamia, New Delhi, 110025, India
| | - Zoya Malik
- Department of Biosciences, Jamia Millia Islamia, New Delhi, 110025, India
- Centre of Excellence in Unani Medicine (Pharmacognosy and Pharmacology), Bioactive Natural Product Laboratory, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi, 110062, India
| | - Syed Akhtar Husain
- Department of Biosciences, Jamia Millia Islamia, New Delhi, 110025, India
| | - Sayeed Ahmad
- Centre of Excellence in Unani Medicine (Pharmacognosy and Pharmacology), Bioactive Natural Product Laboratory, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi, 110062, India.
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Suzuki S, Morita Y, Ishige S, Kai K, Kawasaki K, Matsushita K, Ogura K, Miyoshi-Akiyama† T, Shimizu T. Effects of quorum sensing-interfering agents, including macrolides and furanone C-30, and an efflux pump inhibitor on nitrosative stress sensitivity in Pseudomonas aeruginosa. MICROBIOLOGY (READING, ENGLAND) 2024; 170:001464. [PMID: 38900549 PMCID: PMC11263931 DOI: 10.1099/mic.0.001464] [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: 03/08/2024] [Accepted: 05/21/2024] [Indexed: 06/21/2024]
Abstract
Long-term administration of certain macrolides is efficacious in patients with persistent pulmonary Pseudomonas aeruginosa infection, despite how limited the clinically achievable concentrations are, being far below their MICs. An increase in the sub-MIC of macrolide exposure-dependent sensitivity to nitrosative stress is a typical characteristic of P. aeruginosa. However, a few P. aeruginosa clinical isolates do not respond to sub-MIC of macrolide treatment. Therefore, we examined the effects of sub-MIC of erythromycin (EM) on the sensitivity to nitrosative stress together with an efflux pump inhibitor (EPI) phenylalanine arginyl β-naphthylamide (PAβN). The sensitivity to nitrosative stress increased, suggesting that the efflux pump was involved in inhibiting the sub-MIC of macrolide effect. Analysis using efflux pump-mutant P. aeruginosa revealed that MexAB-OprM, MexXY-OprM, and MexCD-OprJ are factors in reducing the sub-MIC of macrolide effect. Since macrolides interfere with quorum sensing (QS), we demonstrated that the QS-interfering agent furanone C-30 (C-30) producing greater sensitivity to nitric oxide (NO) stress than EM. The effect of C-30 was decreased by overproduction of MexAB-OprM. To investigate whether the increase in the QS-interfering agent exposure-dependent sensitivity to nitrosative stress is characteristic of P. aeruginosa clinical isolates, we examined the viability of P. aeruginosa treated with NO. Although treatment with EM could reduce cell viability, a high variability in EM effects was observed. Conversely, C-30 was highly effective at reducing cell viability. Treatment with both C-30 and PAβN was sufficiently effective against the remaining isolates. Therefore, the combination of a QS-interfering agent and an EPI could be effective in treating P. aeruginosa infections.
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Affiliation(s)
- Shin Suzuki
- Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chiba, 260-8670, Japan
- Division of Laboratory Medicine, Chiba University Hospital, 1-8-1 Inohana, Chiba, 260-8677, Japan
| | - Yuji Morita
- Department of Infection Control Science, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo, 204-8588, Japan
| | - Shota Ishige
- Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chiba, 260-8670, Japan
| | - Kiyohiro Kai
- Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chiba, 260-8670, Japan
| | - Kenji Kawasaki
- Division of Laboratory Medicine, Chiba University Hospital, 1-8-1 Inohana, Chiba, 260-8677, Japan
| | - Kazuyuki Matsushita
- Division of Laboratory Medicine, Chiba University Hospital, 1-8-1 Inohana, Chiba, 260-8677, Japan
| | - Kohei Ogura
- Laboratory of Basic and Applied Molecular Biotechnology, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho, Uji, Kyoto, 6110011, Japan
| | - Tohru Miyoshi-Akiyama†
- Pathogenic Microbe Laboratory, Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo, 162-8655, Japan
| | - Takeshi Shimizu
- Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chiba, 260-8670, Japan
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Yu Z, Shi X, Wang Z. Structures and Efflux Mechanisms of the AcrAB-TolC Pump. Subcell Biochem 2024; 104:1-16. [PMID: 38963480 DOI: 10.1007/978-3-031-58843-3_1] [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: 07/05/2024]
Abstract
The global emergence of multidrug resistance (MDR) in gram-negative bacteria has become a matter of worldwide concern. MDR in these pathogens is closely linked to the overexpression of certain efflux pumps, particularly the resistance-nodulation-cell division (RND) efflux pumps. Inhibition of these pumps presents an attractive and promising strategy to combat antibiotic resistance, as the efflux pump inhibitors can effectively restore the potency of existing antibiotics. AcrAB-TolC is one well-studied RND efflux pump, which transports a variety of substrates, therefore providing resistance to a broad spectrum of antibiotics. To develop effective pump inhibitors, a comprehensive understanding of the structural aspect of the AcrAB-TolC efflux pump is imperative. Previous studies on this pump's structure have been limited to individual components or in vitro determination of fully assembled pumps. Recent advancements in cellular cryo-electron tomography (cryo-ET) have provided novel insights into this pump's assembly and functional mechanism within its native cell membrane environment. Here, we present a summary of the structural data regarding the AcrAB-TolC efflux pump, shedding light on its assembly pathway and operational mechanism.
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Affiliation(s)
- Zhili Yu
- Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, USA
| | - Xiaodong Shi
- Jiangsu Province Key Laboratory of Anesthesiology and Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Zhao Wang
- Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, USA.
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.
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Coppola D, Buonocore C, Palisse M, Tedesco P, de Pascale D. Exploring Oceans for Curative Compounds: Potential New Antimicrobial and Anti-Virulence Molecules against Pseudomonas aeruginosa. Mar Drugs 2022; 21:9. [PMID: 36662182 PMCID: PMC9865402 DOI: 10.3390/md21010009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/16/2022] [Accepted: 12/20/2022] [Indexed: 12/28/2022] Open
Abstract
Although several antibiotics are already widely used against a large number of pathogens, the discovery of new antimicrobial compounds with new mechanisms of action is critical today in order to overcome the spreading of antimicrobial resistance among pathogen bacteria. In this regard, marine organisms represent a potential source of a wide diversity of unique secondary metabolites produced as an adaptation strategy to survive in competitive and hostile environments. Among the multidrug-resistant Gram-negative bacteria, Pseudomonas aeruginosa is undoubtedly one of the most important species due to its high intrinsic resistance to different classes of antibiotics on the market and its ability to cause serious therapeutic problems. In the present review, we first discuss the general mechanisms involved in the antibiotic resistance of P. aeruginosa. Subsequently, we list the marine molecules identified up until now showing activity against P. aeruginosa, dividing them according to whether they act as antimicrobial or anti-virulence compounds.
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Affiliation(s)
- Daniela Coppola
- Department of Ecosustainable Marine Biotechnology, Stazione Zoologica Anton Dohrn, Via Ammiraglio Ferdinando Acton 55, 80133 Naples, Italy
| | - Carmine Buonocore
- Department of Ecosustainable Marine Biotechnology, Stazione Zoologica Anton Dohrn, Via Ammiraglio Ferdinando Acton 55, 80133 Naples, Italy
| | - Morgan Palisse
- Département des Sciences de la Vie et de la Terre, Université de Caen Normandie, Boulevard Maréchal Juin CS, CEDEX, 14032 Caen, France
| | - Pietro Tedesco
- Department of Ecosustainable Marine Biotechnology, Stazione Zoologica Anton Dohrn, Via Ammiraglio Ferdinando Acton 55, 80133 Naples, Italy
| | - Donatella de Pascale
- Department of Ecosustainable Marine Biotechnology, Stazione Zoologica Anton Dohrn, Via Ammiraglio Ferdinando Acton 55, 80133 Naples, Italy
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Law JP, Wood AJ, Friman VP. The Effects of Antibiotic Combination Treatments on Pseudomonas aeruginosa Tolerance Evolution and Coexistence with Stenotrophomonas maltophilia. Microbiol Spectr 2022; 10:e0184222. [PMID: 36453898 PMCID: PMC9769631 DOI: 10.1128/spectrum.01842-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 11/09/2022] [Indexed: 12/03/2022] Open
Abstract
The Pseudomonas aeruginosa bacterium is a common pathogen of cystic fibrosis (CF) patients due to its ability to evolve resistance to antibiotics during treatments. While P. aeruginosa resistance evolution is well-characterized in monocultures, it is less well-understood in polymicrobial CF infections. Here, we investigated how exposure to ciprofloxacin, colistin, or tobramycin antibiotics, administered at sub-minimum inhibitory concentration (MIC) doses, both alone and in combination, shaped the tolerance evolution of P. aeruginosa (PAO1 lab and clinical CF LESB58 strains) in the absence and presence of a commonly co-occurring species, Stenotrophomonas maltophilia. The increases in antibiotic tolerances were primarily driven by the presence of that antibiotic in the treatment. We observed a reciprocal cross-tolerance between ciprofloxacin and tobramycin, and, when combined, the selected antibiotics increased the MICs for all of the antibiotics. Though the presence of S. maltophilia did not affect the tolerance or the MIC evolution, it drove P. aeruginosa into extinction more frequently in the presence of tobramycin due to its relatively greater innate tobramycin tolerance. In contrast, P. aeruginosa dominated and drove S. maltophilia extinct in most other treatments. Together, our findings suggest that besides driving high-level antibiotic tolerance evolution, sub-MIC antibiotic exposure can alter competitive bacterial interactions, leading to target pathogen extinctions in multispecies communities. IMPORTANCE Cystic fibrosis (CF) is a genetic condition that results in thick mucus secretions in the lungs that are susceptible to chronic bacterial infections. The bacterial pathogen Pseudomonas aeruginosa is often associated with morbidity in CF and is difficult to treat due to its high resistance to antibiotics. The resistance evolution of Pseudomonas aeruginosa is poorly understood in polymicrobial infections that are typical of CF. To study this, we exposed P. aeruginosa to sublethal concentrations of ciprofloxacin, colistin, or tobramycin antibiotics in the absence and presence of a commonly co-occurring CF species, Stenotrophomonas maltophilia. We found that low-level antibiotic concentrations selected for high-level antibiotic resistance. While P. aeruginosa dominated in most antibiotic treatments, S. maltophilia drove it into extinction in the presence of tobramycin due to an innately higher tobramycin resistance. Our findings suggest that, besides driving high-level antibiotic tolerance evolution, sublethal antibiotic exposure can magnify competition in bacterial communities, which can lead to target pathogen extinctions in multispecies communities.
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Affiliation(s)
- Jack P. Law
- Department of Biology, University of York, York, United Kingdom
| | - A. Jamie Wood
- Department of Biology, University of York, York, United Kingdom
- Department of Mathematics, University of York, York, United Kingdom
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Wang N, Chen X, Luo J, Deng F, Shi F, Wu Q, Huang Y, Ouyang Q, Qin R, Zhou H. Artemisinin derivative DHA27 enhances the antibacterial effect of aminoglycosides against Pseudomonas aeruginosa by inhibiting mRNA expression of aminoglycoside-modifying enzymes. Front Pharmacol 2022; 13:970400. [PMID: 36353502 PMCID: PMC9637796 DOI: 10.3389/fphar.2022.970400] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 10/10/2022] [Indexed: 09/08/2024] Open
Abstract
Bacterial resistance is becoming increasingly serious, the present study aimed to investigate the mechanism of antibacterial sensitization effect of DHA27 combined with tobramycin in tobramycin-resistant Pseudomonas aeruginosa (PA). We found that DHA27 combined with aminoglycosides had an antibacterial sensitization effect on PA. Tobramycin, owing to its lower toxic and side effects, was selected to further study the molecular mechanism of drug combination. A sublethal-dose bacterial challenge/sepsis mouse model was established to study the protective effect of DHA27 plus tobramycin. Scanning electron microscopy was used to investigate whether DHA27 exerts the antibacterial sensitization effect by directly affecting bacterial morphology. The effect of DHA27 on daunorubicin accumulation in bacteria was studied, and quantitative reverse transcription PCR was used to study the effect of DHA27 plus tobramycin on 16S rRNA methyltransferase and aminoglycoside-modifying enzyme mRNA expression. Twenty clinical isolates of PA were found to be tobramycin resistant; DHA27 plus tobramycin had a significant antibacterial sensitization effect on many of these resistant strains. DHA27 plus tobramycin reduced the bacterial load in the spleen and lungs of sepsis model mice and levels of proinflammatory cytokines interleukin-1β (IL-1β) and interferon-γ (IFN-γ). DHA27 plus tobramycin significantly inhibited the mRNA expression of aminoglycoside-modifying enzymes in bacteria. DHA27 combined with AGs had an antibacterial sensitization effect on PA; the molecular mechanism underlying this effect is closely related to the inhibition of the mRNA expression of aminoglycoside-modifying enzymes, especially aac(3)-II.
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Affiliation(s)
- Nuoyan Wang
- Key Laboratory of Basic Pharmacology, Ministry of Education and Joint Laboratory of International Cooperation, Ministry of Education of Characteristic Ethnic Medicine, College of Pharmacy, Zunyi Medical University, Zunyi, China
| | - Xuemin Chen
- Key Laboratory of Basic Pharmacology, Ministry of Education and Joint Laboratory of International Cooperation, Ministry of Education of Characteristic Ethnic Medicine, College of Pharmacy, Zunyi Medical University, Zunyi, China
| | - Jing Luo
- Key Laboratory of Basic Pharmacology, Ministry of Education and Joint Laboratory of International Cooperation, Ministry of Education of Characteristic Ethnic Medicine, College of Pharmacy, Zunyi Medical University, Zunyi, China
| | - Fei Deng
- Key Laboratory of Basic Pharmacology, Ministry of Education and Joint Laboratory of International Cooperation, Ministry of Education of Characteristic Ethnic Medicine, College of Pharmacy, Zunyi Medical University, Zunyi, China
| | - Fuguo Shi
- Key Laboratory of Basic Pharmacology, Ministry of Education and Joint Laboratory of International Cooperation, Ministry of Education of Characteristic Ethnic Medicine, College of Pharmacy, Zunyi Medical University, Zunyi, China
| | - Qin Wu
- Key Laboratory of Basic Pharmacology, Ministry of Education and Joint Laboratory of International Cooperation, Ministry of Education of Characteristic Ethnic Medicine, College of Pharmacy, Zunyi Medical University, Zunyi, China
| | - Yasi Huang
- Key Laboratory of Basic Pharmacology, Ministry of Education and Joint Laboratory of International Cooperation, Ministry of Education of Characteristic Ethnic Medicine, College of Pharmacy, Zunyi Medical University, Zunyi, China
| | - Qin Ouyang
- Department of Pharmaceutical Chemistry, College of Pharmacy, Army Medical University (The Third Military Medical University), Chongqing, China
| | - Rongxin Qin
- Department of Pharmacology, College of Pharmacy, Army Medical University (The Third Military Medical University), Chongqing, China
| | - Hong Zhou
- Key Laboratory of Basic Pharmacology, Ministry of Education and Joint Laboratory of International Cooperation, Ministry of Education of Characteristic Ethnic Medicine, College of Pharmacy, Zunyi Medical University, Zunyi, China
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Che S, Liang Y, Chen Y, Wu W, Liu R, Zhang Q, Bartlam M. Structure of Pseudomonas aeruginosa spermidine dehydrogenase: a polyamine oxidase with a novel heme-binding fold. FEBS J 2022; 289:1911-1928. [PMID: 34741591 DOI: 10.1111/febs.16264] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 10/31/2021] [Accepted: 11/04/2021] [Indexed: 11/29/2022]
Abstract
The opportunistic pathogen Pseudomonas aeruginosa can utilize polyamines (including putrescine, cadaverine, 4-aminobutyrate, spermidine, and spermine) as its sole source of carbon and nitrogen. Spermidine dehydrogenase (SpdH) is a component of one of the two polyamine utilization pathways identified in P. aeruginosa, but little is known about its structure and function. Here, we report the first crystal structure of SpdH from P. aeruginosa to 1.85 Å resolution. The resulting core structure confirms that SpdH belongs to the polyamine oxidase (PAO) family with flavin-binding and substrate-binding domains. A unique N-terminal extension wraps around the flavin-binding domain of SpdH and is required for heme binding, placing a heme cofactor in close proximity to the FAD cofactor. Structural and mutational analysis reveals that residues in the putative active site at the re side of the FAD isoalloxazine ring form part of the catalytic machinery. PaSpdH features an unusual active site and lacks the conserved lysine that forms part of a lysine-water-flavin N5 atom interaction in other PAO enzymes characterized to date. Mutational analysis further confirms that heme is required for catalytic activity. This work provides an important starting point for understanding the role of SpdH, which occurs universally in P. aeruginosa strains, in polyamine metabolism.
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Affiliation(s)
- Shiyou Che
- State Key Laboratory of Medicinal Chemical Biology, Nankai International Advanced Research Institute (Shenzhen Futian), College of Life Sciences, Nankai University, Tianjin, China
| | - Yakun Liang
- State Key Laboratory of Medicinal Chemical Biology, Nankai International Advanced Research Institute (Shenzhen Futian), College of Life Sciences, Nankai University, Tianjin, China
| | - Yujing Chen
- State Key Laboratory of Medicinal Chemical Biology, Nankai International Advanced Research Institute (Shenzhen Futian), College of Life Sciences, Nankai University, Tianjin, China
| | - Wenyue Wu
- State Key Laboratory of Medicinal Chemical Biology, Nankai International Advanced Research Institute (Shenzhen Futian), College of Life Sciences, Nankai University, Tianjin, China
| | - Ruihua Liu
- State Key Laboratory of Medicinal Chemical Biology, Nankai International Advanced Research Institute (Shenzhen Futian), College of Life Sciences, Nankai University, Tianjin, China
| | - Qionglin Zhang
- State Key Laboratory of Medicinal Chemical Biology, Nankai International Advanced Research Institute (Shenzhen Futian), College of Life Sciences, Nankai University, Tianjin, China
| | - Mark Bartlam
- State Key Laboratory of Medicinal Chemical Biology, Nankai International Advanced Research Institute (Shenzhen Futian), College of Life Sciences, Nankai University, Tianjin, China
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Chen M, Shi X, Yu Z, Fan G, Serysheva II, Baker ML, Luisi BF, Ludtke SJ, Wang Z. In situ structure of the AcrAB-TolC efflux pump at subnanometer resolution. Structure 2022; 30:107-113.e3. [PMID: 34506732 PMCID: PMC8741639 DOI: 10.1016/j.str.2021.08.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/22/2021] [Accepted: 08/18/2021] [Indexed: 01/09/2023]
Abstract
The tripartite AcrAB-TolC assembly, which spans both the inner and outer membranes in Gram-negative bacteria, is an efflux pump that contributes to multidrug resistance. Here, we present the in situ structure of full-length Escherichia coli AcrAB-TolC determined at 7 Å resolution by electron cryo-tomography. The TolC channel penetrates the outer membrane bilayer through to the outer leaflet and exhibits two different configurations that differ by a 60° rotation relative to the AcrB position in the pump assembly. AcrA protomers interact directly with the inner membrane and with AcrB via an interface located in proximity to the AcrB ligand-binding pocket. Our structural analysis suggests that these AcrA-bridged interactions underlie an allosteric mechanism for transmitting drug-evoked signals from AcrB to the TolC channel within the pump. Our study demonstrates the power of in situ electron cryo-tomography, which permits critical insights into the function of bacterial efflux pumps.
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Affiliation(s)
- Muyuan Chen
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Xiaodong Shi
- Jiangsu Province Key Laboratory of Anesthesiology and Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Zhili Yu
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Guizhen Fan
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School at the University of Texas Health Science Center, Houston, TX 77030, USA
| | - Irina I Serysheva
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School at the University of Texas Health Science Center, Houston, TX 77030, USA
| | - Matthew L Baker
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School at the University of Texas Health Science Center, Houston, TX 77030, USA
| | - Ben F Luisi
- Department of Biochemistry, University of Cambridge, Cambridge CB21GA, UK
| | - Steven J Ludtke
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zhao Wang
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
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Berberine Derivatives as Pseudomonas aeruginosa MexXY-OprM Inhibitors: Activity and In Silico Insights. Molecules 2021; 26:molecules26216644. [PMID: 34771051 PMCID: PMC8587913 DOI: 10.3390/molecules26216644] [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: 10/07/2021] [Revised: 10/28/2021] [Accepted: 10/29/2021] [Indexed: 11/17/2022] Open
Abstract
The natural alkaloid berberine has been demonstrated to inhibit the Pseudomonas aeruginosa multidrug efflux system MexXY-OprM, which is responsible for tobramycin extrusion by binding the inner membrane transporter MexY. To find a structure with improved inhibitory activity, we compared by molecular dynamics investigations the binding affinity of berberine and three aromatic substituents towards the three polymorphic sequences of MexY found in P. aeruginosa (PAO1, PA7, and PA14). The synergy of the combinations of berberine or berberine derivatives/tobramycin against the same strains was then evaluated by checkerboard and time-kill assays. The in silico analysis evidenced different binding modes depending on both the structure of the berberine derivative and the specific MexY polymorphism. In vitro assays showed an evident MIC reduction (32-fold and 16-fold, respectively) and a 2–3 log greater killing effect after 2 h of exposure to the combinations of 13-(2-methylbenzyl)- and 13-(4-methylbenzyl)-berberine with tobramycin against the tobramycin-resistant strain PA7, a milder synergy (a 4-fold MIC reduction) against PAO1 and PA14, and no synergy against the ΔmexXY strain K1525, confirming the MexY-specific binding and the computational results. These berberine derivatives could thus be considered new hit compounds to select more effective berberine substitutions and their common path of interaction with MexY as the starting point for the rational design of novel MexXY-OprM inhibitors.
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Evaluation of Antibiotic Tolerance in Pseudomonas aeruginosa for Aminoglycosides and Its Predicted Gene Regulations through In-Silico Transcriptomic Analysis. MICROBIOLOGY RESEARCH 2021. [DOI: 10.3390/microbiolres12030045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Pseudomonas aeruginosa causes chronic infections, such as cystic fibrosis, endocarditis, bacteremia, and sepsis, which are life-threatening and difficult to treat. The lack of antibiotic response in P. aeruginosa is due to adaptive resistance mechanism, which prevents the entry of antibiotics into the cytosol of the cell to achieve tolerance. Among the different groups of antibiotics, aminoglycosides are used as a parenteral antibiotic for the treatment of P. aeruginosa. This study aimed to determine the kinetics of antibiotic tolerance and gene expression changes in P. aeruginosa exposed to amikacin, gentamicin, and tobramycin. These antibiotics were exposed to P. aeruginosa at their MICs and the experimental setup was monitored for 72 h, followed by the measurement of optical density every 12 h. The growth of P. aeruginosa in the MICs of antibiotics represented the kinetics of antibiotic tolerance in amikacin, gentamicin, and tobramycin. The transcriptomic profile of antibiotic exposed P. aeruginosa PA14 was taken from the Gene Expression Omnibus (GEO), NCBI as microarray datasets. The gene expressions of two datasets were compared by test versus control. Tobramycin-exposed P. aeruginosa failed to develop tolerance in MICs of 0.5 µg/mL, 1 µg/mL, and 1.5 µg/mL, whereas amikacin- and gentamicin-treated P. aeruginosa developed tolerance. This illustrated the superior in vitro response of tobramycin over gentamicin and amikacin. Further, in silico transcriptomic analysis of tobramycin-treated P. aeruginosa resulted in differentially expressed genes (DEGs), enriched in 16s rRNA methyltransferase E, B, and L, alginate biosynthesis genes, and several proteins of the type II secretion system (T2SS) and type III secretion system (T3SS). The regulation of mucA in alginate biosynthesis, and gidB in RNA methyltransferases, suggested an increased antibiotic response and a low probability of developing resistance during tobramycin treatment. The use of tobramycin as a parenteral antibiotic with its synergistic combination might combat P. aeruginosa with increased response.
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Butler DA, Rana AP, Krapp F, Patel SR, Huang Y, Ozer EA, Hauser AR, Bulman ZP. Optimizing aminoglycoside selection for KPC-producing Klebsiella pneumoniae with the aminoglycoside-modifying enzyme (AME) gene aac(6')-Ib. J Antimicrob Chemother 2021; 76:671-679. [PMID: 33326561 DOI: 10.1093/jac/dkaa480] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 10/22/2020] [Indexed: 01/26/2023] Open
Abstract
OBJECTIVES KPC-producing Klebsiella pneumoniae (KPC-Kp) isolates commonly co-harbour the aminoglycoside-modifying enzyme (AME) gene aac(6')-Ib, which encodes an AME that can confer resistance to some of the commercially available aminoglycosides. We sought to determine the influence of AAC(6')-Ib in KPC-Kp on the pharmacodynamic activity of aminoglycosides. METHODS Six KPC-Kp clinical isolates, three with and three without aac(6')-Ib, were analysed. Using these isolates, the bacterial killing of amikacin, gentamicin and tobramycin was assessed in static time-kill experiments. The pharmacodynamic activity of the aminoglycosides was then assessed in a dynamic one-compartment infection model over 72 h using simulated human pharmacokinetics of once-daily dosing with amikacin (15 mg/kg), gentamicin (5 mg/kg) and tobramycin (5 mg/kg). RESULTS At clinically relevant aminoglycoside concentrations in time-kill experiments and the dynamic one-compartment model, gentamicin was more active than amikacin or tobramycin against the isolates harbouring aac(6')-Ib. Amikacin, gentamicin and tobramycin all showed progressively reduced bacterial killing with exposure to repeated doses against most isolates in the dynamic one-compartment model. MIC values were generally not a good predictor of gentamicin pharmacodynamic activity against KPC-Kp, but were more reliable for amikacin and tobramycin. CONCLUSIONS Gentamicin may be preferred over amikacin or tobramycin for treatment of KPC-Kp infections. However, gentamicin MICs are not a consistent predictor of its pharmacodynamic activity and unexpected treatment failures are possible.
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Affiliation(s)
- David A Butler
- University of Illinois at Chicago College of Pharmacy, Chicago, IL, USA
| | - Amisha P Rana
- University of Illinois at Chicago College of Pharmacy, Chicago, IL, USA
| | - Fiorella Krapp
- Northwestern University Feinberg School of Medicine, Chicago, IL, USA.,Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano, Lima, Peru
| | - Shitalben R Patel
- University of Illinois at Chicago College of Pharmacy, Chicago, IL, USA
| | - Yanqin Huang
- University of Illinois at Chicago College of Pharmacy, Chicago, IL, USA
| | - Egon A Ozer
- Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Alan R Hauser
- Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Zackery P Bulman
- University of Illinois at Chicago College of Pharmacy, Chicago, IL, USA
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12
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Yip CH, Mahalingam S, Wan KL, Nathan S. Prodigiosin inhibits bacterial growth and virulence factors as a potential physiological response to interspecies competition. PLoS One 2021; 16:e0253445. [PMID: 34161391 PMCID: PMC8221495 DOI: 10.1371/journal.pone.0253445] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 06/06/2021] [Indexed: 11/19/2022] Open
Abstract
Prodigiosin, a red linear tripyrrole pigment, has long been recognised for its antimicrobial property. However, the physiological contribution of prodigiosin to the survival of its producing hosts still remains undefined. Hence, the aim of this study was to investigate the biological role of prodigiosin from Serratia marcescens, particularly in microbial competition through its antimicrobial activity, towards the growth and secreted virulence factors of four clinical pathogenic bacteria (methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, Salmonella enterica serovar Typhimurium and Pseudomonas aeruginosa) as well as Staphylococcus aureus and Escherichia coli. Prodigiosin was first extracted from S. marcescens and its purity confirmed by absorption spectrum, high performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrophotometry (LC-MS/MS). The extracted prodigiosin was antagonistic towards all the tested bacteria. A disc-diffusion assay showed that prodigiosin is more selective towards Gram-positive bacteria and inhibited the growth of MRSA, S. aureus and E. faecalis and Gram-negative E. coli. A minimum inhibitory concentration of 10 μg/μL of prodigiosin was required to inhibit the growth of S. aureus, E. coli and E. faecalis whereas > 10 μg/μL was required to inhibit MRSA growth. We further assessed the effect of prodigiosin towards bacterial virulence factors such as haemolysin and production of protease as well as on biofilm formation. Prodigiosin did not inhibit haemolysis activity of clinically associated bacteria but was able to reduce protease activity for MRSA, E. coli and E. faecalis as well as decrease E. faecalis, Salmonella Typhimurium and E. coli biofilm formation. Results of this study show that in addition to its role in inhibiting bacterial growth, prodigiosin also inhibits the bacterial virulence factor protease production and biofilm formation, two strategies employed by bacteria in response to microbial competition. As clinical pathogens were more resistant to prodigiosin, we propose that prodigiosin is physiologically important for S. marcescens to compete against other bacteria in its natural soil and surface water environments.
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Affiliation(s)
- Chee-Hoo Yip
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor, Malaysia
| | - Sobina Mahalingam
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor, Malaysia
| | - Kiew-Lian Wan
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor, Malaysia
| | - Sheila Nathan
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor, Malaysia
- * E-mail:
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13
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Mangiaterra G, Cedraro N, Laudadio E, Minnelli C, Citterio B, Andreoni F, Mobbili G, Galeazzi R, Biavasco F. The Natural Alkaloid Berberine Can Reduce the Number of Pseudomonas aeruginosa Tolerant Cells. JOURNAL OF NATURAL PRODUCTS 2021; 84:993-1001. [PMID: 33848161 DOI: 10.1021/acs.jnatprod.0c01151] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The eradication of recurrent Pseudomonas aeruginosa (PA) lung infection in cystic fibrosis (CF) patients may be hampered by the development of persistent bacterial forms, which can tolerate antibiotics through efflux pump overexpression. After demonstrating the efflux pump inhibitory effect of the alkaloid berberine on the PA MexXY-OprM efflux pump, in this study, we tested its ability (80/320 μg/mL) to enhance tobramycin (20xMIC/1000xMIC) activity against PA planktonic/biofilm cultures. Preliminary investigations of the involvement of MexY in PA tolerance to tobramycin treatment, performed on the isogenic pair PA K767 (wild type)/K1525 (ΔmexY) growing in planktonic and biofilm cultures, demonstrated that the ΔmexY mutant K1525 produced a lower (100 and 10 000 times, respectively) amount of tolerant cells than that of the wild type. Next, we grew broth cultures of PAO1, PA14, and 20 PA clinical isolates (of which 13 were from CF patients) in the presence of 20xMIC tobramycin with and without berberine 80 μg/mL. Accordingly, most strains showed a greater (from 10- to 1000-fold) tolerance reduction in the presence of berberine. These findings highlight the involvement of the MexXY-OprM system in the tobramycin tolerance of PA and suggest that berberine may be used in new valuable therapeutic combinations to counteract persister survival.
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Affiliation(s)
- Gianmarco Mangiaterra
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona 60131, Italy
| | - Nicholas Cedraro
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona 60131, Italy
| | - Emiliano Laudadio
- Department of Materials, Environmental Sciences and Urban Planning, Polytechnic University of Marche, Ancona 60131, Italy
| | - Cristina Minnelli
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona 60131, Italy
| | - Barbara Citterio
- Department of Biomolecular Sciences, sect. Biotechnology, University of Urbino "Carlo Bo", Fano 61032, Italy
| | - Francesca Andreoni
- Department of Biomolecular Sciences, sect. Biotechnology, University of Urbino "Carlo Bo", Fano 61032, Italy
| | - Giovanna Mobbili
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona 60131, Italy
| | - Roberta Galeazzi
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona 60131, Italy
| | - Francesca Biavasco
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona 60131, Italy
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Langendonk RF, Neill DR, Fothergill JL. The Building Blocks of Antimicrobial Resistance in Pseudomonas aeruginosa: Implications for Current Resistance-Breaking Therapies. Front Cell Infect Microbiol 2021; 11:665759. [PMID: 33937104 PMCID: PMC8085337 DOI: 10.3389/fcimb.2021.665759] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 03/29/2021] [Indexed: 12/12/2022] Open
Abstract
P. aeruginosa is classified as a priority one pathogen by the World Health Organisation, and new drugs are urgently needed, due to the emergence of multidrug-resistant (MDR) strains. Antimicrobial-resistant nosocomial pathogens such as P. aeruginosa pose unwavering and increasing threats. Antimicrobial stewardship has been a challenge during the COVID-19 pandemic, with a majority of those hospitalized with SARS-CoV2 infection given antibiotics as a safeguard against secondary bacterial infection. This increased usage, along with increased handling of sanitizers and disinfectants globally, may further accelerate the development and spread of cross-resistance to antibiotics. In addition, P. aeruginosa is the primary causative agent of morbidity and mortality in people with the life-shortening genetic disease cystic fibrosis (CF). Prolonged periods of selective pressure, associated with extended antibiotic treatment and the actions of host immune effectors, results in widespread adaptive and acquired resistance in P. aeruginosa found colonizing the lungs of people with CF. This review discusses the arsenal of resistance mechanisms utilized by P. aeruginosa, how these operate under high-stress environments such as the CF lung and how their interconnectedness can result in resistance to multiple antibiotic classes. Intrinsic, adaptive and acquired resistance mechanisms will be described, with a focus on how each layer of resistance can serve as a building block, contributing to multi-tiered resistance to antimicrobial activity. Recent progress in the development of anti-resistance adjuvant therapies, targeting one or more of these building blocks, should lead to novel strategies for combatting multidrug resistant P. aeruginosa. Anti-resistance adjuvant therapy holds great promise, not least because resistance against such therapeutics is predicted to be rare. The non-bactericidal nature of anti-resistance adjuvants reduce the selective pressures that drive resistance. Anti-resistance adjuvant therapy may also be advantageous in facilitating efficacious use of traditional antimicrobials, through enhanced penetration of the antibiotic into the bacterial cell. Promising anti-resistance adjuvant therapeutics and targets will be described, and key remaining challenges highlighted. As antimicrobial stewardship becomes more challenging in an era of emerging and re-emerging infectious diseases and global conflict, innovation in antibiotic adjuvant therapy can play an important role in extending the shelf-life of our existing antimicrobial therapeutic agents.
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Affiliation(s)
- R. Frèdi Langendonk
- Institute of Infection, Veterinary and Ecological Science, University of Liverpool, Liverpool, United Kingdom
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15
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Maiden MM, Waters CM. Triclosan depletes the membrane potential in Pseudomonas aeruginosa biofilms inhibiting aminoglycoside induced adaptive resistance. PLoS Pathog 2020; 16:e1008529. [PMID: 33125434 PMCID: PMC7657502 DOI: 10.1371/journal.ppat.1008529] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 11/11/2020] [Accepted: 09/15/2020] [Indexed: 12/18/2022] Open
Abstract
Biofilm-based infections are difficult to treat due to their inherent resistance to antibiotic treatment. Discovering new approaches to enhance antibiotic efficacy in biofilms would be highly significant in treating many chronic infections. Exposure to aminoglycosides induces adaptive resistance in Pseudomonas aeruginosa biofilms. Adaptive resistance is primarily the result of active antibiotic export by RND-type efflux pumps, which use the proton motive force as an energy source. We show that the protonophore uncoupler triclosan depletes the membrane potential of biofilm growing P. aeruginosa, leading to decreased activity of RND-type efflux pumps. This disruption results in increased intracellular accumulation of tobramycin and enhanced antimicrobial activity in vitro. In addition, we show that triclosan enhances tobramycin effectiveness in vivo using a mouse wound model. Combining triclosan with tobramycin is a new anti-biofilm strategy that targets bacterial energetics, increasing the susceptibility of P. aeruginosa biofilms to aminoglycosides.
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Affiliation(s)
- Michael M. Maiden
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
- The BEACON Center for The Study of Evolution in Action, Michigan State University, East Lansing, Michigan, United States of America
| | - Christopher M. Waters
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
- The BEACON Center for The Study of Evolution in Action, Michigan State University, East Lansing, Michigan, United States of America
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16
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Khan M, Stapleton F, Summers S, Rice SA, Willcox MDP. Antibiotic Resistance Characteristics of Pseudomonas aeruginosa Isolated from Keratitis in Australia and India. Antibiotics (Basel) 2020; 9:antibiotics9090600. [PMID: 32937932 PMCID: PMC7559795 DOI: 10.3390/antibiotics9090600] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/08/2020] [Accepted: 09/09/2020] [Indexed: 02/07/2023] Open
Abstract
This study investigated genomic differences in Australian and Indian Pseudomonas aeruginosa isolates from keratitis (infection of the cornea). Overall, the Indian isolates were resistant to more antibiotics, with some of those isolates being multi-drug resistant. Acquired genes were related to resistance to fluoroquinolones, aminoglycosides, beta-lactams, macrolides, sulphonamides, and tetracycline and were more frequent in Indian (96%) than in Australian (35%) isolates (p = 0.02). Indian isolates had large numbers of gene variations (median 50,006, IQR = 26,967-50,600) compared to Australian isolates (median 26,317, IQR = 25,681-33,780). There were a larger number of mutations in the mutL and uvrD genes associated with the mismatch repair (MMR) system in Indian isolates, which may result in strains losing their efficacy for DNA repair. The number of gene variations were greater in isolates carrying MMR system genes or exoU. In the phylogenetic division, the number of core genes were similar in both groups, but Indian isolates had larger numbers of pan genes (median 6518, IQR = 6040-6935). Clones related to three different sequence types-ST308, ST316, and ST491-were found among Indian isolates. Only one clone, ST233, containing two strains was present in Australian isolates. The most striking differences between Australian and Indian isolates were carriage of exoU (that encodes a cytolytic phospholipase) in Indian isolates and exoS (that encodes for GTPase activator activity) in Australian isolates, large number of acquired resistance genes, greater changes to MMR genes, and a larger pan genome as well as increased overall genetic variation in the Indian isolates.
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Affiliation(s)
- Mahjabeen Khan
- School of Optometry and Vision Science, UNSW, Sydney, NSW 2052, Australia; (M.K.); (F.S.)
| | - Fiona Stapleton
- School of Optometry and Vision Science, UNSW, Sydney, NSW 2052, Australia; (M.K.); (F.S.)
| | - Stephen Summers
- The Singapore Centre for Environment Life Sciences Engineering (SCELSE), The School of Biological Sciences, Nanyang Technological University, Singapore 639798, Singapore; (S.S.); (S.A.R.)
| | - Scott A. Rice
- The Singapore Centre for Environment Life Sciences Engineering (SCELSE), The School of Biological Sciences, Nanyang Technological University, Singapore 639798, Singapore; (S.S.); (S.A.R.)
- The ithree Institute, The University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Mark D. P. Willcox
- School of Optometry and Vision Science, UNSW, Sydney, NSW 2052, Australia; (M.K.); (F.S.)
- Correspondence: ; Tel.: +61-2-9385-4164
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17
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van Duijkeren E, Schwarz C, Bouchard D, Catry B, Pomba C, Baptiste KE, Moreno MA, Rantala M, Ružauskas M, Sanders P, Teale C, Wester AL, Ignate K, Kunsagi Z, Jukes H. The use of aminoglycosides in animals within the EU: development of resistance in animals and possible impact on human and animal health: a review. J Antimicrob Chemother 2020; 74:2480-2496. [PMID: 31002332 DOI: 10.1093/jac/dkz161] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Aminoglycosides (AGs) are important antibacterial agents for the treatment of various infections in humans and animals. Following extensive use of AGs in humans, food-producing animals and companion animals, acquired resistance among human and animal pathogens and commensal bacteria has emerged. Acquired resistance occurs through several mechanisms, but enzymatic inactivation of AGs is the most common one. Resistance genes are often located on mobile genetic elements, facilitating their spread between different bacterial species and between animals and humans. AG resistance has been found in many different bacterial species, including those with zoonotic potential such as Salmonella spp., Campylobacter spp. and livestock-associated MRSA. The highest risk is anticipated from transfer of resistant enterococci or coliforms (Escherichia coli) since infections with these pathogens in humans would potentially be treated with AGs. There is evidence that the use of AGs in human and veterinary medicine is associated with the increased prevalence of resistance. The same resistance genes have been found in isolates from humans and animals. Evaluation of risk factors indicates that the probability of transmission of AG resistance from animals to humans through transfer of zoonotic or commensal foodborne bacteria and/or their mobile genetic elements can be regarded as high, although there are no quantitative data on the actual contribution of animals to AG resistance in human pathogens. Responsible use of AGs is of great importance in order to safeguard their clinical efficacy for human and veterinary medicine.
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Affiliation(s)
| | - Christine Schwarz
- Federal Office of Consumer Protection and Food Safety, Berlin, Germany
| | - Damien Bouchard
- French Agency for Food, Environmental, and Occupational Safety, National Agency for Veterinary Medicinal Products, Fougères, France
| | - Boudewijn Catry
- Sciensano, Brussels, Belgium
- Faculty of Medicine, Université libre de Bruxelles (ULB), Brussels, Belgium
| | - Constança Pomba
- Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
| | | | - Miguel A Moreno
- Faculty of Veterinary Medicine, Complutense University, Madrid, Spain
| | - Merja Rantala
- Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | | | - Pascal Sanders
- French Agency for Food, Environmental, and Occupational Safety, Fougères Laboratory, Fougères, France
| | | | | | | | | | - Helen Jukes
- Veterinary Medicines Directorate, Addlestone, UK
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TpiA is a Key Metabolic Enzyme That Affects Virulence and Resistance to Aminoglycoside Antibiotics through CrcZ in Pseudomonas aeruginosa. mBio 2020; 11:mBio.02079-19. [PMID: 31911486 PMCID: PMC6946797 DOI: 10.1128/mbio.02079-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The increase in bacterial resistance against antibiotics imposes a severe threat to public health. It is urgent to identify new drug targets and develop novel antimicrobials. Metabolic homeostasis of bacteria plays an essential role in their virulence and resistance to antibiotics. Recent studies demonstrated that antibiotic efficacies can be improved by modulating the bacterial metabolism. Pseudomonas aeruginosa is an important opportunistic human pathogen that causes various infections. The bacterium is intrinsically resistant to antibiotics. In this study, we provide clear evidence that TpiA (triosephosphate isomerase) plays an essential role in the metabolism of P. aeruginosa and influences bacterial virulence and antibiotic resistance. The significance of this work is in identifying a key enzyme in the metabolic network, which will provide clues as to the development of novel treatment strategies against infections caused by P. aeruginosa. Carbon metabolism plays an essential role in bacterial pathogenesis and susceptibility to antibiotics. In Pseudomonas aeruginosa, Crc, Hfq, and a small RNA, CrcZ, are central regulators of carbon metabolism. By screening mutants of genes involved in carbon metabolism, we found that mutation of the tpiA gene reduces the expression of the type III secretion system (T3SS) and bacterial resistance to aminoglycoside antibiotics. TpiA is a triosephosphate isomerase that reversibly converts glyceraldehyde 3-phosphate to dihydroxyacetone phosphate, a key step connecting glucose metabolism with glycerol and phospholipid metabolisms. We found that mutation of the tpiA gene enhances the bacterial carbon metabolism, respiration, and oxidative phosphorylation, which increases the membrane potential and promotes the uptake of aminoglycoside antibiotics. Further studies revealed that the level of CrcZ is increased in the tpiA mutant due to enhanced stability. Mutation of the crcZ gene in the tpiA mutant background restored the expression of the T3SS genes and the bacterial resistance to aminoglycoside antibiotics. Overall, this study reveals an essential role of TpiA in the metabolism, virulence, and antibiotic resistance in P. aeruginosa.
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19
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Barbosa C, Römhild R, Rosenstiel P, Schulenburg H. Evolutionary stability of collateral sensitivity to antibiotics in the model pathogen Pseudomonas aeruginosa. eLife 2019; 8:e51481. [PMID: 31658946 PMCID: PMC6881144 DOI: 10.7554/elife.51481] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 10/21/2019] [Indexed: 12/27/2022] Open
Abstract
Evolution is at the core of the impending antibiotic crisis. Sustainable therapy must thus account for the adaptive potential of pathogens. One option is to exploit evolutionary trade-offs, like collateral sensitivity, where evolved resistance to one antibiotic causes hypersensitivity to another one. To date, the evolutionary stability and thus clinical utility of this trade-off is unclear. We performed a critical experimental test on this key requirement, using evolution experiments with Pseudomonas aeruginosa, and identified three main outcomes: (i) bacteria commonly failed to counter hypersensitivity and went extinct; (ii) hypersensitivity sometimes converted into multidrug resistance; and (iii) resistance gains frequently caused re-sensitization to the previous drug, thereby maintaining the trade-off. Drug order affected the evolutionary outcome, most likely due to variation in the effect size of collateral sensitivity, epistasis among adaptive mutations, and fitness costs. Our finding of robust genetic trade-offs and drug-order effects can guide design of evolution-informed antibiotic therapy.
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Affiliation(s)
- Camilo Barbosa
- Department of Evolutionary Ecology and GeneticsUniversity of KielKielGermany
| | - Roderich Römhild
- Department of Evolutionary Ecology and GeneticsUniversity of KielKielGermany
- Max Planck Institute for Evolutionary BiologyPlönGermany
| | | | - Hinrich Schulenburg
- Department of Evolutionary Ecology and GeneticsUniversity of KielKielGermany
- Max Planck Institute for Evolutionary BiologyPlönGermany
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20
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Kawalek A, Modrzejewska M, Zieniuk B, Bartosik AA, Jagura-Burdzy G. Interaction of ArmZ with the DNA-binding domain of MexZ induces expression of mexXY multidrug efflux pump genes and antimicrobial resistance in Pseudomonas aeruginosa. Antimicrob Agents Chemother 2019; 63:AAC.01199-19. [PMID: 31527038 PMCID: PMC6879243 DOI: 10.1128/aac.01199-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 09/13/2019] [Indexed: 12/17/2022] Open
Abstract
Multidrug efflux pumps play an important role in antibiotic resistance in bacteria. In Pseudomonas aeruginosa, MexXY pump provides intrinsic resistance to many antimicrobials, including aminoglycosides. The expression of mexXY operon is negatively regulated by MexZ repressor. The repression is alleviated in response to the antibiotic-induced ribosome stress, which results in increased synthesis of anti-repressor ArmZ, interacting with MexZ. The molecular mechanism of MexZ inactivation by ArmZ is not known. Here, we showed that the N-terminal part of MexZ, encompassing the DNA-binding domain, is required for interaction with ArmZ. Using the bacterial two hybrid system based mutant screening and pull-down analyses we identified substitutions in MexZ that diminished (R3S, K6E, R13H) or completely impaired (K53E) the interaction with ArmZ without blocking MexZ activity as a transcriptional repressor. Introduction of corresponding mexZ missense mutations into P aeruginosa PAO1161 chromosome impaired (mexZ K6E, mexZ R13H) or blocked (mexZ K53E) tetracycline mediated induction of mexY expression. Concomitantly, PAO1161 mexZ K53E strain was more susceptible to aminoglycosides. The identified residues are highly conserved in MexZ-like transcriptional regulators found in bacterial genomes encoding both MexX/MexY/MexZ and ArmZ/PA5470 orthologs, suggesting that a similar mechanism may contribute to induction of efflux mediated resistance in other bacterial species. Overall, our data shed light on the molecular mechanism of ArmZ mediated induction of intrinsic antimicrobial resistance in P. aeruginosa.
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Affiliation(s)
- Adam Kawalek
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Department of Microbial Biochemistry, Warsaw, Poland
| | - Magdalena Modrzejewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Department of Microbial Biochemistry, Warsaw, Poland
| | - Bartlomiej Zieniuk
- Department of Epidemiology and Clinical Microbiology, National Medicines Institute, Warsaw, Poland
| | - Aneta Agnieszka Bartosik
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Department of Microbial Biochemistry, Warsaw, Poland
| | - Grazyna Jagura-Burdzy
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Department of Microbial Biochemistry, Warsaw, Poland
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Dandachi I, Chaddad A, Hanna J, Matta J, Daoud Z. Understanding the Epidemiology of Multi-Drug Resistant Gram-Negative Bacilli in the Middle East Using a One Health Approach. Front Microbiol 2019; 10:1941. [PMID: 31507558 PMCID: PMC6716069 DOI: 10.3389/fmicb.2019.01941] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 08/07/2019] [Indexed: 12/16/2022] Open
Abstract
In the last decade, extended-spectrum cephalosporin and carbapenem resistant Gram-negative bacilli (GNB) have been extensively reported in the literature as being disseminated in humans but also in animals and the environment. These resistant organisms often cause treatment challenges due to their wide spectrum of antibiotic resistance. With the emergence of colistin resistance in animals and its subsequent detection in humans, the situation has worsened. Several studies reported the transmission of resistant organisms from animals to humans. Studies from the middle east highlight the spread of resistant organisms in hospitals and to a lesser extent in livestock and the environment. In view of the recent socio-economical conflicts that these countries are facing in addition to the constant population mobilization; we attempt in this review to highlight the gaps of the prevalence of resistance, antibiotic consumption reports, infection control measures and other risk factors contributing in particular to the spread of resistance in these countries. In hospitals, carbapenemases producers appear to be dominant. In contrast, extended spectrum beta lactamases (ESBL) and colistin resistance are becoming a serious problem in animals. This is mainly due to the continuous use of colistin in veterinary medicine even though it is now abandoned in the human sphere. In the environment, despite the small number of reports, ESBL and carbapenemases producers were both detected. This highlights the importance of the latter as a bridge between humans and animals in the transmission chain. In this review, we note that in the majority of the Middle Eastern area, little is known about the level of antibiotic consumption especially in the community and animal farms. Furthermore, some countries are currently facing issues with immigrants, poverty and poor living conditions which has been imposed by the civil war crisis. This all greatly facilitates the dissemination of resistance in all environments. In the one health concept, this work re-emphasizes the need to have global intervention measures to avoid dissemination of antibiotic resistance in humans, animals and the environment in Middle Eastern countries.
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Affiliation(s)
- Iman Dandachi
- Faculty of Medicine and Medical Sciences, Clinical Microbiology Laboratory, University of Balamand, Beirut, Lebanon
| | - Amer Chaddad
- Faculty of Medicine and Medical Sciences, Clinical Microbiology Laboratory, University of Balamand, Beirut, Lebanon
| | - Jason Hanna
- Faculty of Medicine and Medical Sciences, Clinical Microbiology Laboratory, University of Balamand, Beirut, Lebanon
| | - Jessika Matta
- Faculty of Medicine and Medical Sciences, Clinical Microbiology Laboratory, University of Balamand, Beirut, Lebanon
| | - Ziad Daoud
- Faculty of Medicine and Medical Sciences, Clinical Microbiology Laboratory, University of Balamand, Beirut, Lebanon
- Division of Clinical Microbiology, Saint George Hospital University Medical Center, Beirut, Lebanon
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Laudadio E, Cedraro N, Mangiaterra G, Citterio B, Mobbili G, Minnelli C, Bizzaro D, Biavasco F, Galeazzi R. Natural Alkaloid Berberine Activity against Pseudomonas aeruginosa MexXY-Mediated Aminoglycoside Resistance: In Silico and in Vitro Studies. JOURNAL OF NATURAL PRODUCTS 2019; 82:1935-1944. [PMID: 31274312 DOI: 10.1021/acs.jnatprod.9b00317] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The multidrug efflux system MexXY-OprM, inside the resistance-nodulation-division family, is a major determinant of aminoglycoside resistance in Pseudomonas aeruginosa. In the fight aimed to identify potential efflux pump inhibitors among natural compounds, the alkaloid berberine emerged as a putative inhibitor of MexXY-OprM. In this work, we elucidated its interaction with the extrusor protein MexY and assessed its synergistic activity with aminoglycosides. In particular, we built an in silico model for the MexY protein in its trimeric association using both AcrB (E. coli) and MexB (P. aeruginosa) as 3D templates. This model has been stabilized in the bacterial cytoplasmic membrane using a molecular dynamics approach and used for ensemble docking to obtain the binding site mapping. Then, through dynamic docking, we assessed its binding affinity and its synergism with aminoglycosides focusing on tobramycin, which is widely used in the treatment of pulmonary infections. In vitro assays validated the data obtained: the results showed a 2-fold increase of the inhibitory activity and 2-4 log increase of the killing activity of the association berberine-tobramycin compared to those of tobramycin alone against 13/28 tested P. aeruginosa clinical isolates. From hemolytic assays, we preliminarily assessed berberine's low toxicity.
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Affiliation(s)
- Emiliano Laudadio
- Dipartimento S.I.M.A.U. , Università Politecnica delle Marche , Via Brecce Bianche , 60131 , Ancona , Italy
| | - Nicholas Cedraro
- Dipartimento di Scienze della Vita e dell'Ambiente , Università Politecnica delle Marche , Via Brecce Bianche , 60131 , Ancona , Italy
| | - Gianmarco Mangiaterra
- Dipartimento di Scienze della Vita e dell'Ambiente , Università Politecnica delle Marche , Via Brecce Bianche , 60131 , Ancona , Italy
| | - Barbara Citterio
- Dipartimento di Scienze Biomolecolari, sez. di Biotecnologie , Università degli Studi di Urbino "Carlo Bo" , 61029 , Urbino , Italy
| | - Giovanna Mobbili
- Dipartimento di Scienze della Vita e dell'Ambiente , Università Politecnica delle Marche , Via Brecce Bianche , 60131 , Ancona , Italy
| | - Cristina Minnelli
- Dipartimento di Scienze della Vita e dell'Ambiente , Università Politecnica delle Marche , Via Brecce Bianche , 60131 , Ancona , Italy
| | - Davide Bizzaro
- Dipartimento di Scienze della Vita e dell'Ambiente , Università Politecnica delle Marche , Via Brecce Bianche , 60131 , Ancona , Italy
| | - Francesca Biavasco
- Dipartimento di Scienze della Vita e dell'Ambiente , Università Politecnica delle Marche , Via Brecce Bianche , 60131 , Ancona , Italy
| | - Roberta Galeazzi
- Dipartimento di Scienze della Vita e dell'Ambiente , Università Politecnica delle Marche , Via Brecce Bianche , 60131 , Ancona , Italy
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Abdul-Mutakabbir JC, Kebriaei R, Jorgensen SCJ, Rybak MJ. Teaching an Old Class New Tricks: A Novel Semi-Synthetic Aminoglycoside, Plazomicin. Infect Dis Ther 2019; 8:155-170. [PMID: 30850956 PMCID: PMC6522576 DOI: 10.1007/s40121-019-0239-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Indexed: 11/30/2022] Open
Abstract
The emergence of multi-drug resistant (MDR) Gram-negative pathogens has become a serious worldwide health concern. Gram-negative bacteria such as Enterobacteriaceae (Klebsiella pneumoniae, Escherichia coli, Enterobacter spp.,) Acinetobacter spp., and Pseudomonas aeruginosa have rendered most antibiotics inactive, leaving aminoglycosides and polymyxins. Plazomicin (formerly ACHN-490), is a neoglycoside with unique structural modifications to the aminoglycoside pharmacophore that impart activity against many MDR Gram-negative organisms. ACHN-490 was recently approved by the US Food and Drug Administration for the treatment of complicated urinary tract infections caused by MDR Enterobacteriaceae. In this era of increasing Gram-negative resistance, it is imperative to critically evaluate new antibiotics so that we understand how to use them optimally. The objective of this article is to discuss available data detailing plazomicin's biochemistry, pharmacokinetic/pharmacodynamic characteristics, in-vitro activity and current progress in clinical trials. In addition, plazomicin's potential role in therapy for the treatment of MDR Gram-negative infections will be discussed.
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Affiliation(s)
- Jacinda C Abdul-Mutakabbir
- Anti-Infective Research Laboratory, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, USA
| | - Razieh Kebriaei
- Anti-Infective Research Laboratory, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, USA
| | - Sarah C J Jorgensen
- Anti-Infective Research Laboratory, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, USA
| | - Michael J Rybak
- Anti-Infective Research Laboratory, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, USA.
- Division of Infectious Diseases, School of Medicine, Wayne State University, Detroit, MI, USA.
- Detroit Receiving Hospital, Detroit, MI, USA.
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Mikhaleva TV, Zakharova OI, Ilyasov PV. Antibiotic Resistance: Modern Approaches and Ways to Overcome It (Review). APPL BIOCHEM MICRO+ 2019. [DOI: 10.1134/s000368381902011x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Maiden MM, Zachos MP, Waters CM. The ionophore oxyclozanide enhances tobramycin killing of Pseudomonas aeruginosa biofilms by permeabilizing cells and depolarizing the membrane potential. J Antimicrob Chemother 2019; 74:894-906. [PMID: 30624737 PMCID: PMC6735725 DOI: 10.1093/jac/dky545] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 10/31/2018] [Accepted: 11/29/2018] [Indexed: 12/30/2022] Open
Abstract
OBJECTIVES To assess the ability of oxyclozanide to enhance tobramycin killing of Pseudomonas aeruginosa biofilms and elucidate its mechanism of action. METHODS Twenty-four hour biofilms formed by the P. aeruginosa strain PAO1 and cystic fibrosis (CF) isolates were tested for susceptibility to oxyclozanide and tobramycin killing using BacTiter-Glo™ and cfu. Biofilm dispersal was measured using crystal violet staining. Membrane potential and permeabilization were quantified using DiOC2(3) and TO-PRO-3, respectively. RESULTS Here we show that the ionophore anthelmintic oxyclozanide, combined with tobramycin, significantly increased killing of P. aeruginosa biofilms over each treatment alone. This combination also significantly accelerated the killing of cells within biofilms and stationary phase cultures and it was effective against 4/6 CF clinical isolates tested, including a tobramycin-resistant strain. Oxyclozanide enhanced the ability of additional aminoglycosides and tetracycline to kill P. aeruginosa biofilms. Finally, oxyclozanide permeabilized cells within the biofilm, reduced the membrane potential and increased tobramycin accumulation within cells of mature P. aeruginosa biofilms. CONCLUSIONS Oxyclozanide enhances aminoglycoside and tetracycline activity against P. aeruginosa biofilms by reducing membrane potential, permeabilizing cells and enhancing tobramycin accumulation within biofilms. We propose that oxyclozanide counteracts the adaptive resistance response of P. aeruginosa to aminoglycosides, increasing both their maximum activity and rate of killing. As oxyclozanide is widely used in veterinary medicine for the treatment of parasitic worm infections, this combination could offer a new approach for the treatment of biofilm-based P. aeruginosa infections, repurposing oxyclozanide as an anti-biofilm agent.
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Affiliation(s)
- Michael M Maiden
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI, USA
| | - Mitchell P Zachos
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Christopher M Waters
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI, USA
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26
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Rowbotham NJ, Palser SC, Smith SJ, Smyth AR. Infection prevention and control in cystic fibrosis: a systematic review of interventions. Expert Rev Respir Med 2019; 13:425-434. [DOI: 10.1080/17476348.2019.1595594] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Nicola J Rowbotham
- Evidence Based Child Health Group, Division of Child Health, Obstetrics & Gynaecology, Queens Medical Centre, Nottingham, UK
| | - Sally C Palser
- Evidence Based Child Health Group, Division of Child Health, Obstetrics & Gynaecology, Queens Medical Centre, Nottingham, UK
| | - Sherie J Smith
- Evidence Based Child Health Group, Division of Child Health, Obstetrics & Gynaecology, Queens Medical Centre, Nottingham, UK
| | - Alan R Smyth
- Evidence Based Child Health Group, Division of Child Health, Obstetrics & Gynaecology, Queens Medical Centre, Nottingham, UK
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Loss of the Two-Component System TctD-TctE in Pseudomonas aeruginosa Affects Biofilm Formation and Aminoglycoside Susceptibility in Response to Citric Acid. mSphere 2019; 4:4/2/e00102-19. [PMID: 30842268 PMCID: PMC6403454 DOI: 10.1128/msphere.00102-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The two-component system TctD-TctE is important for regulating the uptake of tricarboxylic acids in Pseudomonas aeruginosa TctD-TctE accomplishes this through derepression of the gene opdH, which encodes a tricarboxylic acid-specific porin. Previous work from our lab revealed that TctD-TctE in P. aeruginosa also has a role in resistance to aminoglycoside antibiotics. The aim of this study was to further characterize the role of TctD-TctE in P. aeruginosa in the presence of citric acid. Here it was found that deletion of P. aeruginosa PA14 TctD-TctE (ΔtctED) resulted in a 4-fold decrease in the biofilm bactericidal concentrations of the aminoglycosides tobramycin and gentamicin when citric acid was present in nutrient media. Tobramycin accumulation assays demonstrated that deletion of TctD-TctE resulted in an increase in the amount of tobramycin retained in biofilm cells. The PA14 wild type responded to increasing concentrations of citric acid by producing less biofilm. In contrast, the amount of ΔtctED mutant biofilm formation remained constant or enhanced. Furthermore, the ΔtctED strain was incapable of growing on citric acid as a sole carbon source and was highly reduced in its ability to grow in the presence of citric acid even when an additional carbon source was available. Use of phenotypic and genetic microarrays found that this growth deficiency of the ΔtctED mutant is unique to citric acid and that multiple metabolic genes are dysregulated. This work demonstrates that TctD-TctE in P. aeruginosa has a role in biofilm development that is dependent on citric acid and that is separate from the previously characterized involvement in resistance to antibiotics.IMPORTANCE Nutrient availability is an important contributor to the ability of bacteria to establish successful infections in a host. Pseudomonas aeruginosa is an opportunistic pathogen in humans causing infections that are difficult to treat. In part, its success is attributable to a high degree of metabolic versatility. P. aeruginosa is able to sense and respond to varied and limited nutrient stress in the host environment. Two-component systems are important sensors-regulators of cellular responses to environmental stresses, such as those encountered in the host. This work demonstrates that the response by the two-component system TctD-TctE to the presence of citric acid has a role in biofilm formation, aminoglycoside susceptibility, and growth in P. aeruginosa.
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Zhou S, Zhuang Y, Zhu X, Yao F, Li H, Li H, Zou X, Wu J, Zhou H, Nuer G, Huang Y, Li S, Peng Q. YhjX Regulates the Growth of Escherichia coli in the Presence of a Subinhibitory Concentration of Gentamicin and Mediates the Adaptive Resistance to Gentamicin. Front Microbiol 2019; 10:1180. [PMID: 31191496 PMCID: PMC6545925 DOI: 10.3389/fmicb.2019.01180] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 05/09/2019] [Indexed: 02/05/2023] Open
Abstract
The mechanisms of adaptive resistance of Escherichia coli to aminoglycosides remain unclear. Our RNA-Seq study found that expression of yhjX was markedly upregulated during initial exposure to subinhibitory concentrations of gentamicin. The expression of yhjX was then downregulated dramatically during a second exposure to gentamicin compared to the first exposure. YhjX encodes a putative transporter of the major facilitator superfamily, which is known to be the sole target of the YpdA/YpdB two-component system, the expression of which is highly and specifically induced by pyruvate. To investigate the effect of yhjX on the adaptive resistance of E. coli, in the present study, we constructed yhjX deletion and complemented strains of E. coli ATCC25922. Changes in extracellular pyruvate levels of wide-type and yhjX mutant were measured to determine whether YhjX functions as a pyruvate transporter. The results showed that yhjX deletion improved the growth of E. coli in medium containing subinhibitory concentrations of gentamicin. The yhjX deletion mutant did not exhibit adaptive resistance to subinhibitory concentrations of gentamicin. YhjX might not function as a pyruvate efflux pump in E. coli but was associated with the decrease following a sharp increase in the extracellular pyruvate level. Our findings indicate that yhjX regulates the growth of E. coli in the presence of a subinhibitory concentration of gentamicin and mediates the adaptive resistance to gentamicin.
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Affiliation(s)
- Shuqin Zhou
- Department of Anesthesiology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Yijing Zhuang
- Department of Science and Education, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Xiaojuan Zhu
- Department of Anesthesiology, First People’s Hospital of Kashi, Kashi, China
| | - Fen Yao
- Department of Pharmacology, Shantou University Medical College, Shantou, China
| | - Haiyan Li
- Department of Pharmacology, Shantou University Medical College, Shantou, China
| | - Huifang Li
- Department of Anesthesiology, First People’s Hospital of Kashi, Kashi, China
| | - Xiaoguang Zou
- Department of Pharmacy, First People’s Hospital of Kashi, Kashi, China
| | - Jianhua Wu
- Department of Science and Education, First People’s Hospital of Kashi, Kashi, China
| | - Huifang Zhou
- Department of Clinical Laboratory, First People’s Hospital of Kashi, Kashi, China
| | - Gulibaier Nuer
- Department of Anesthesiology, First People’s Hospital of Kashi, Kashi, China
| | - Yuanchun Huang
- Department of Clinical Laboratory, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Shao Li
- Department of Hepatobiliary II, Zhujiang Hospital of Southern Medical University, Guangzhou, China
| | - Qing Peng
- Department of Hepatobiliary II, Zhujiang Hospital of Southern Medical University, Guangzhou, China
- *Correspondence: Qing Peng,
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Pang Z, Raudonis R, Glick BR, Lin TJ, Cheng Z. Antibiotic resistance in Pseudomonas aeruginosa: mechanisms and alternative therapeutic strategies. Biotechnol Adv 2018; 37:177-192. [PMID: 30500353 DOI: 10.1016/j.biotechadv.2018.11.013] [Citation(s) in RCA: 975] [Impact Index Per Article: 162.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 11/21/2018] [Accepted: 11/24/2018] [Indexed: 01/09/2023]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that is a leading cause of morbidity and mortality in cystic fibrosis patients and immunocompromised individuals. Eradication of P. aeruginosa has become increasingly difficult due to its remarkable capacity to resist antibiotics. Strains of Pseudomonas aeruginosa are known to utilize their high levels of intrinsic and acquired resistance mechanisms to counter most antibiotics. In addition, adaptive antibiotic resistance of P. aeruginosa is a recently characterized mechanism, which includes biofilm-mediated resistance and formation of multidrug-tolerant persister cells, and is responsible for recalcitrance and relapse of infections. The discovery and development of alternative therapeutic strategies that present novel avenues against P. aeruginosa infections are increasingly demanded and gaining more and more attention. Although mostly at the preclinical stages, many recent studies have reported several innovative therapeutic technologies that have demonstrated pronounced effectiveness in fighting against drug-resistant P. aeruginosa strains. This review highlights the mechanisms of antibiotic resistance in P. aeruginosa and discusses the current state of some novel therapeutic approaches for treatment of P. aeruginosa infections that can be further explored in clinical practice.
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Affiliation(s)
- Zheng Pang
- Department of Pathology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Renee Raudonis
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Bernard R Glick
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Tong-Jun Lin
- Department of Pathology, Dalhousie University, Halifax, NS B3H 4R2, Canada; Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada; Department of Pediatrics, IWK Health Centre, Halifax, NS B3K 6R8, Canada
| | - Zhenyu Cheng
- Department of Pathology, Dalhousie University, Halifax, NS B3H 4R2, Canada; Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
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Fan Z, Xu C, Pan X, Dong Y, Ren H, Jin Y, Bai F, Cheng Z, Jin S, Wu W. Mechanisms of RsaL mediated tolerance to ciprofloxacin and carbenicillin in Pseudomonas aeruginosa. Curr Genet 2018; 65:213-222. [DOI: 10.1007/s00294-018-0863-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 06/05/2018] [Accepted: 06/22/2018] [Indexed: 02/07/2023]
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Ramaswamy VK, Vargiu AV, Malloci G, Dreier J, Ruggerone P. Molecular Determinants of the Promiscuity of MexB and MexY Multidrug Transporters of Pseudomonas aeruginosa. Front Microbiol 2018; 9:1144. [PMID: 29910784 PMCID: PMC5992780 DOI: 10.3389/fmicb.2018.01144] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 05/14/2018] [Indexed: 12/14/2022] Open
Abstract
Secondary multidrug transporters of the resistance-nodulation-cell division (RND) superfamily contribute crucially to antibiotic resistance in Gram-negative bacteria. Compared to the most studied transporter AcrB of Escherichia coli, little is known about the molecular determinants of distinct polyspecificities of the most important RND transporters MexB and MexY of Pseudomonas aeruginosa. In an effort to add knowledge on this topic, we performed an exhaustive atomic-level comparison of the main putative recognition sites (access and deep binding pockets) in these two Mex transporters. We identified an underlying link between some structural, chemical and dynamical features of the binding pockets and the physicochemical nature of the corresponding substrates recognized by either one or both pumps. In particular, mosaic-like lipophilic and electrostatic surfaces of the binding pockets provide for both proteins several multifunctional sites for diffuse binding of diverse substrates. Specific lipophilicity signatures of the weakly conserved deep pocket suggest a key role of this site as a selectivity filter as in Acr transporters. Finally, the different dynamics of the bottom-loop in MexB and MexY support its possible role in binding of large substrates. Our work represents the first comparative study of the major RND transporters in P. aeruginosa and also the first structure-based study of MexY, for which no experimental structure is available yet.
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Affiliation(s)
| | - Attilio V Vargiu
- Department of Physics, University of Cagliari, Monserrato, Italy
| | - Giuliano Malloci
- Department of Physics, University of Cagliari, Monserrato, Italy
| | - Jürg Dreier
- Basilea Pharmaceutica International Ltd., Basel, Switzerland
| | - Paolo Ruggerone
- Department of Physics, University of Cagliari, Monserrato, Italy
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Modeling the Emergence of Antibiotic Resistance in the Environment: an Analytical Solution for the Minimum Selection Concentration. Antimicrob Agents Chemother 2018; 62:AAC.01686-17. [PMID: 29263062 DOI: 10.1128/aac.01686-17] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 12/07/2017] [Indexed: 11/20/2022] Open
Abstract
Environmental antibiotic risk management requires an understanding of how subinhibitory antibiotic concentrations contribute to the spread of resistance. We develop a simple model of competition between sensitive and resistant bacterial strains to predict the minimum selection concentration (MSC), the lowest level of antibiotic at which resistant bacteria are selected. We present an analytical solution for the MSC based on the routinely measured MIC, the selection coefficient (sc) that expresses fitness differences between strains, the intrinsic net growth rate, and the shape of the bacterial growth dose-response curve with antibiotic or metal exposure (the Hill coefficient [κ]). We calibrated the model by optimizing the Hill coefficient to fit previously reported experimental growth rate difference data. The model fit varied among nine compound-taxon combinations examined but predicted the experimentally observed MSC/MIC ratio well (R2 ≥ 0.95). The shape of the antibiotic response curve varied among compounds (0.7 ≤ κ ≤ 10.5), with the steepest curve being found for the aminoglycosides streptomycin and kanamycin. The model was sensitive to this antibiotic response curve shape and to the sc, indicating the importance of fitness differences between strains for determining the MSC. The MSC can be >1 order of magnitude lower than the MIC, typically by the factor scκ This study provides an initial quantitative depiction and a framework for a research agenda to examine the growing evidence of selection for resistant bacterial communities at low environmental antibiotic concentrations.
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Antibiotic Persistence as a Metabolic Adaptation: Stress, Metabolism, the Host, and New Directions. Pharmaceuticals (Basel) 2018; 11:ph11010014. [PMID: 29389876 PMCID: PMC5874710 DOI: 10.3390/ph11010014] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 01/25/2018] [Accepted: 01/27/2018] [Indexed: 12/16/2022] Open
Abstract
Persistence is a phenomenon during which a small fraction of a total bacterial population survives treatment with high concentrations of antibiotics for an extended period of time. In conjunction with biofilms, antibiotic persisters represent a major cause of recalcitrant and recurring infections, resulting in significant morbidity and mortality. In this review, we discuss the clinical significance of persister cells and the central role of bacterial metabolism in their formation, specifically with respect to carbon catabolite repression, sugar metabolism, and growth regulation. Additionally, we will examine persister formation as an evolutionary strategy used to tolerate extended periods of stress and discuss some of the response mechanisms implicated in their formation. To date, the vast majority of the mechanistic research examining persistence has been conducted in artificial in vitro environments that are unlikely to be representative of host conditions. Throughout this review, we contextualize the existing body of literature by discussing how in vivo conditions may create ecological niches that facilitate the development of persistence. Lastly, we identify how the development of next-generation sequencing and other “big data” tools may enable researchers to examine persistence mechanisms within the host to expand our understanding of their clinical importance.
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Mensa J, Barberán J, Soriano A, Llinares P, Marco F, Cantón R, Bou G, del Castillo JG, Maseda E, Azanza JR, Pasquau J, García-Vidal C, Reguera JM, Sousa D, Gómez J, Montejo M, Borges M, Torres A, Alvarez-Lerma F, Salavert M, Zaragoza R, Oliver A. Antibiotic selection in the treatment of acute invasive infections by Pseudomonas aeruginosa: Guidelines by the Spanish Society of Chemotherapy. REVISTA ESPANOLA DE QUIMIOTERAPIA : PUBLICACION OFICIAL DE LA SOCIEDAD ESPANOLA DE QUIMIOTERAPIA 2018; 31:78-100. [PMID: 29480677 PMCID: PMC6159363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Pseudomonas aeruginosa is characterized by a notable intrinsic resistance to antibiotics, mainly mediated by the expression of inducible chromosomic β-lactamases and the production of constitutive or inducible efflux pumps. Apart from this intrinsic resistance, P. aeruginosa possess an extraordinary ability to develop resistance to nearly all available antimicrobials through selection of mutations. The progressive increase in resistance rates in P. aeruginosa has led to the emergence of strains which, based on their degree of resistance to common antibiotics, have been defined as multidrug resistant, extended-resistant and panresistant strains. These strains are increasingly disseminated worldwide, progressively complicating the treatment of P. aeruginosa infections. In this scenario, the objective of the present guidelines was to review and update published evidence for the treatment of patients with acute, invasive and severe infections caused by P. aeruginosa. To this end, mechanisms of intrinsic resistance, factors favoring development of resistance during antibiotic exposure, prevalence of resistance in Spain, classical and recently appeared new antibiotics active against P. aeruginosa, pharmacodynamic principles predicting efficacy, clinical experience with monotherapy and combination therapy, and principles for antibiotic treatment were reviewed to elaborate recommendations by the panel of experts for empirical and directed treatment of P. aeruginosa invasive infections.
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Affiliation(s)
- José Mensa
- Servicio de Enfermedades Infecciosas, Hospital Clinic, Barcelona, Spain
| | - José Barberán
- Servicio de Medicina Enfermedades infecciosas, Hospital Universitario HM Montepríncipe, Universidad San Pablo CEU. Madrid, Spain
| | - Alex Soriano
- Servicio de Enfermedades Infecciosas, Hospital Clinic, Barcelona, Spain
| | - Pedro Llinares
- Unidad de Enfermedades Infecciosas, Complejo Hospitalario Universitario A Coruña, Spain
| | - Francesc Marco
- Servicio de Microbiología, Hospital Clinic, Barcelona, Spain
| | - Rafael Cantón
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS). Madrid, Spain
| | - German Bou
- Servicio de Microbiología, Complejo Hospitalario Universitario A Coruña, Spain
| | | | - Emilio Maseda
- Servicio de Anestesiología, Hospital Universitario La Paz, Madrid, Spain
| | - José Ramón Azanza
- Servicio de Farmacología, Clínica Universitaria de Navarra, Pamplona, Spain
| | - Juan Pasquau
- Servicio de Enfermedades Infecciosas, Hospital Universitario Virgen de la Nieves, Granada, Spain
| | | | - José María Reguera
- Servicio de Enfermedades Infecciosas, Hospital Universitario Carlos Haya, Málaga, Spain
| | - Dolores Sousa
- Unidad de Enfermedades Infecciosas, Complejo Hospitalario Universitario A Coruña, Spain
| | - Joaquín Gómez
- Servicio de Enfermedades Infecciosas, Hospital Clínico Universitario Virgen de la Arrixaca, Murcia, Spain
| | - Miguel Montejo
- Servicio de Enfermedades Infecciosas, Hospital Universitario Cruces, Bilbao, Spain
| | - Marcio Borges
- Servicio de Medicina Intensiva, Hospital Son Llátzer, Palma de Mallorca, Spain
| | - Antonio Torres
- Departamento de Neumología, Hospital Clinic, Barcelona, Spain
| | | | - Miguel Salavert
- Unidad de Enfermedades Infecciosas. Hospital Univeristario la Fe, Valencia, Spain
| | - Rafael Zaragoza
- Servicio de Medicina Intensiva, Hospital Universitario Dr. Peset, Valencia, Spain
| | - Antonio Oliver
- Servicio de Microbiología, Hospital Universitari Son Espases, Instituto de Investigación Sanitaria Illes Balears (idISBa), Palma de Mallorca, Spain
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Ramanathan B, Jindal HM, Le CF, Gudimella R, Anwar A, Razali R, Poole-Johnson J, Manikam R, Sekaran SD. Next generation sequencing reveals the antibiotic resistant variants in the genome of Pseudomonas aeruginosa. PLoS One 2017; 12:e0182524. [PMID: 28797043 PMCID: PMC5557631 DOI: 10.1371/journal.pone.0182524] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 07/19/2017] [Indexed: 01/29/2023] Open
Abstract
Rapid progress in next generation sequencing and allied computational tools have aided in identification of single nucleotide variants in genomes of several organisms. In the present study, we have investigated single nucleotide polymorphism (SNP) in ten multi-antibiotic resistant Pseudomonas aeruginosa clinical isolates. All the draft genomes were submitted to Rapid Annotations using Subsystems Technology (RAST) web server and the predicted protein sequences were used for comparison. Non-synonymous single nucleotide polymorphism (nsSNP) found in the clinical isolates compared to the reference genome (PAO1), and the comparison of nsSNPs between antibiotic resistant and susceptible clinical isolates revealed insights into the genome variation. These nsSNPs identified in the multi-drug resistant clinical isolates were found to be altering a single amino acid in several antibiotic resistant genes. We found mutations in genes encoding efflux pump systems, cell wall, DNA replication and genes involved in repair mechanism. In addition, nucleotide deletions in the genome and mutations leading to generation of stop codons were also observed in the antibiotic resistant clinical isolates. Next generation sequencing is a powerful tool to compare the whole genomes and analyse the single base pair variations found within the antibiotic resistant genes. We identified specific mutations within antibiotic resistant genes compared to the susceptible strain of the same bacterial species and these findings may provide insights to understand the role of single nucleotide variants in antibiotic resistance.
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Affiliation(s)
- Babu Ramanathan
- Department of Biological Sciences, School of Science and Technology, Sunway University, Kuala Lumpur, Malaysia
- * E-mail: (BR); (SDS)
| | - Hassan Mahmood Jindal
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Cheng Foh Le
- School of Pharmacy, Faculty of Science, University of Nottingham Malaysia Campus, Jalan Broga, Selangor, Malaysia
| | - Ranganath Gudimella
- Sengenics, High Impact Research (HIR), University of Malaya, Kuala Lumpur, Malaysia
| | - Arif Anwar
- Sengenics, High Impact Research (HIR), University of Malaya, Kuala Lumpur, Malaysia
| | - Rozaimi Razali
- Sengenics, High Impact Research (HIR), University of Malaya, Kuala Lumpur, Malaysia
| | - Johan Poole-Johnson
- Sengenics, High Impact Research (HIR), University of Malaya, Kuala Lumpur, Malaysia
| | - Rishya Manikam
- Department of Trauma and Emergency, University Malaya Medical Centre, Kuala Lumpur, Malaysia
| | - Shamala Devi Sekaran
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- * E-mail: (BR); (SDS)
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37
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Yen P, Papin JA. History of antibiotic adaptation influences microbial evolutionary dynamics during subsequent treatment. PLoS Biol 2017; 15:e2001586. [PMID: 28792497 PMCID: PMC5549691 DOI: 10.1371/journal.pbio.2001586] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 07/06/2017] [Indexed: 11/24/2022] Open
Abstract
Antibiotic regimens often include the sequential changing of drugs to limit the development and evolution of resistance of bacterial pathogens. It remains unclear how history of adaptation to one antibiotic can influence the resistance profiles when bacteria subsequently adapt to a different antibiotic. Here, we experimentally evolved Pseudomonas aeruginosa to six 2-drug sequences. We observed drug order-specific effects, whereby adaptation to the first drug can limit the rate of subsequent adaptation to the second drug, adaptation to the second drug can restore susceptibility to the first drug, or final resistance levels depend on the order of the 2-drug sequence. These findings demonstrate how resistance not only depends on the current drug regimen but also the history of past regimens. These order-specific effects may allow for rational forecasting of the evolutionary dynamics of bacteria given knowledge of past adaptations and provide support for the need to consider the history of past drug exposure when designing strategies to mitigate resistance and combat bacterial infections.
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Affiliation(s)
- Phillip Yen
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, United States of America
| | - Jason A. Papin
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, United States of America
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38
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López-Causapé C, Sommer LM, Cabot G, Rubio R, Ocampo-Sosa AA, Johansen HK, Figuerola J, Cantón R, Kidd TJ, Molin S, Oliver A. Evolution of the Pseudomonas aeruginosa mutational resistome in an international Cystic Fibrosis clone. Sci Rep 2017; 7:5555. [PMID: 28717172 PMCID: PMC5514035 DOI: 10.1038/s41598-017-05621-5] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 05/31/2017] [Indexed: 12/18/2022] Open
Abstract
Emergence of epidemic clones and antibiotic resistance development compromises the management of Pseudomonas aeruginosa cystic fibrosis (CF) chronic respiratory infections. Whole genome sequencing (WGS) was used to decipher the phylogeny, interpatient dissemination, WGS mutator genotypes (mutome) and resistome of a widespread clone (CC274), in isolates from two highly-distant countries, Australia and Spain, covering an 18-year period. The coexistence of two divergent CC274 clonal lineages was revealed, but without evident geographical barrier; phylogenetic reconstructions and mutational resistome demonstrated the interpatient transmission of mutators. The extraordinary capacity of P. aeruginosa to develop resistance was evidenced by the emergence of mutations in >100 genes related to antibiotic resistance during the evolution of CC274, catalyzed by mutator phenotypes. While the presence of classical mutational resistance mechanisms was confirmed and correlated with resistance phenotypes, results also showed a major role of unexpected mutations. Among them, PBP3 mutations, shaping up β-lactam resistance, were noteworthy. A high selective pressure for mexZ mutations was evidenced, but we showed for the first time that high-level aminoglycoside resistance in CF is likely driven by mutations in fusA1/fusA2, coding for elongation factor G. Altogether, our results provide valuable information for understanding the evolution of the mutational resistome of CF P. aeruginosa.
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Affiliation(s)
- Carla López-Causapé
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Islas Baleares (IdISBa), Palma de Mallorca, Spain.
| | - Lea Mette Sommer
- Novo Nordisk Foundation Center for Biosustainability, The Technical University of Denmark, Lingby, Denmark
| | - Gabriel Cabot
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Islas Baleares (IdISBa), Palma de Mallorca, Spain
| | - Rosa Rubio
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Islas Baleares (IdISBa), Palma de Mallorca, Spain
| | - Alain A Ocampo-Sosa
- Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla, Instituto de Investigación Marqués de Valdecilla, Santander, Spain
| | - Helle Krogh Johansen
- Novo Nordisk Foundation Center for Biosustainability, The Technical University of Denmark, Lingby, Denmark
| | - Joan Figuerola
- Servicio de Pediatría, Hospital Son Espases, Palma de Mallorca, Spain
| | - Rafael Cantón
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Timothy J Kidd
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.,Child Health Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Soeren Molin
- Novo Nordisk Foundation Center for Biosustainability, The Technical University of Denmark, Lingby, Denmark
| | - Antonio Oliver
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Islas Baleares (IdISBa), Palma de Mallorca, Spain.
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Ciofu O, Rojo-Molinero E, Macià MD, Oliver A. Antibiotic treatment of biofilm infections. APMIS 2017; 125:304-319. [PMID: 28407419 DOI: 10.1111/apm.12673] [Citation(s) in RCA: 237] [Impact Index Per Article: 33.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Accepted: 01/10/2017] [Indexed: 12/24/2022]
Abstract
Bacterial biofilms are associated with a wide range of infections, from those related to exogenous devices, such as catheters or prosthetic joints, to chronic tissue infections such as those occurring in the lungs of cystic fibrosis patients. Biofilms are recalcitrant to antibiotic treatment due to multiple tolerance mechanisms (phenotypic resistance). This causes persistence of biofilm infections in spite of antibiotic exposure which predisposes to antibiotic resistance development (genetic resistance). Understanding the interplay between phenotypic and genetic resistance mechanisms acting on biofilms, as well as appreciating the diversity of environmental conditions of biofilm infections which influence the effect of antibiotics are required in order to optimize the antibiotic treatment of biofilm infections. Here, we review the current knowledge on phenotypic and genetic resistance in biofilms and describe the potential strategies for the antibiotic treatment of biofilm infections. Of note is the optimization of PK/PD parameters in biofilms, high-dose topical treatments, combined and sequential/alternate therapies or the use antibiotic adjuvants.
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Affiliation(s)
- Oana Ciofu
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
| | - Estrella Rojo-Molinero
- Servicio de Microbiología, Hospital Son Espases, Instituto de Investigación Sanitaria de Palma (IdISPa), Palma de Mallorca, Spain
| | - María D Macià
- Servicio de Microbiología, Hospital Son Espases, Instituto de Investigación Sanitaria de Palma (IdISPa), Palma de Mallorca, Spain
| | - Antonio Oliver
- Servicio de Microbiología, Hospital Son Espases, Instituto de Investigación Sanitaria de Palma (IdISPa), Palma de Mallorca, Spain
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40
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Uemura S, Yokota SI, Shiraishi T, Kitagawa M, Hirayama S, Kyan R, Mizuno H, Sawamoto K, Inoue H, Miyamoto A, Narimatsu E. Adaptive Cross-Resistance to Aminoglycoside Antibiotics in Pseudomonas aeruginosa Induced by Topical Dosage of Neomycin. Chemotherapy 2016; 62:121-127. [PMID: 27794569 DOI: 10.1159/000449368] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 08/22/2016] [Indexed: 11/19/2022]
Abstract
BACKGROUND Topical antimicrobial formulations containing neomycin are commonly used to prevent and treat burn infections. However, Pseudomonas aeruginosa shows rapid acquisition of adaptive resistance to neomycin. This study aimed to evaluate the survival of P. aeruginosa during exposure to neomycin at high concentrations comparable to those used in topical formulations, and to investigate the effect of adaptive resistance to neomycin on the susceptibility to other aminoglycosides. METHODS Strain IID1130 [neomycin minimal inhibitory concentration (MIC) = 4 µg/ml] was incubated on an agar medium containing neomycin at high concentrations (8-4,096 µg/ml), and growing colonies were macroscopically observed. Acquisition of adaptive resistance was examined for 5 P. aeruginosa strains. Cells were sequentially passaged on agar medium containing neomycin with step-wise increased concentrations (8-2,048 µg/ml). To assess reversion of antibiotic susceptibility, the resulting colonies were repeatedly subcultured on antibiotic-free agar plates. RESULTS Growing IID1130 colonies were macroscopically detected on a neomycin-containing (2,048 µg/ml) agar plate for 48 h. These cells showed increasing MIC for not only neomycin, but also gentamicin and amikacin; the MIC values were occasionally higher than the breakpoints. When the adapted cells were subcultured on antibiotic-free agar, several passages were required for reversion of susceptibility. CONCLUSIONS Our findings suggest that P. aeruginosa can survive in the presence of neomycin with a concentration typically used in topical dosage forms, and that the acquired adaptive resistance is persistent and is accompanied by cross-resistance to other aminoglycosides.
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Affiliation(s)
- Shuji Uemura
- Department of Emergency Medicine, Sapporo Medical University Hospital, Sapporo, Japan
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41
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Rees VE, Bulitta JB, Oliver A, Tsuji BT, Rayner CR, Nation RL, Landersdorfer CB. Resistance suppression by high-intensity, short-duration aminoglycoside exposure against hypermutable and non-hypermutable Pseudomonas aeruginosa. J Antimicrob Chemother 2016; 71:3157-3167. [PMID: 27521357 DOI: 10.1093/jac/dkw297] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 06/14/2016] [Accepted: 06/23/2016] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVES Hypermutable bacteria are causing a drastic problem via their enhanced ability to become resistant. Our objectives were to compare bacterial killing and resistance emergence between differently shaped tobramycin concentration-time profiles at a given fAUC/MIC, and determine the tobramycin exposure durations that prevent resistance. METHODS Static concentration time-kill studies over 24 h used Pseudomonas aeruginosa WT strains (ATCC 27853 and PAO1) and hypermutable PAOΔmutS. fAUC/MIC values of 36, 72 and 168 were assessed at initial inocula of 106 and 104 cfu/mL (all strains) and 101.2 cfu/mL (PAOΔmutS only) in duplicate. Tobramycin was added at 0 h and removed at 1, 4, 10 or 24 h. Proportions of resistant bacteria and MICs were determined at 24 h. Mechanism-based modelling was conducted. RESULTS For all strains, high tobramycin concentrations over 1 and 4 h resulted in more rapid and extensive initial killing compared with 10 and 24 h exposures at a given fAUC/MIC. No resistance emerged for 1 and 4 h durations of exposure, although extensive regrowth of susceptible bacteria occurred. The 24 h duration of exposure revealed less regrowth, but tobramycin-resistant populations had completely replaced susceptible bacteria by 24 h for the 106 cfu/mL inoculum. The hypermutable PAOΔmutS showed the highest numbers of resistant bacteria. Total and resistant bacterial counts were described well by novel mechanism-based modelling. CONCLUSIONS Extensive resistance emerged for 10 and 24 h durations of exposure, but not for shorter durations. The tobramycin concentration-time profile shape is vital for resistance prevention and should aid the introduction of optimized combination regimens.
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Affiliation(s)
- Vanessa E Rees
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), Parkville, Victoria 3052, Australia
| | - Jürgen B Bulitta
- Center for Pharmacometrics and Systems Pharmacology, College of Pharmacy, University of Florida, Orlando, FL, USA
| | - Antonio Oliver
- Servicio de Microbiología, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria de Palma, Palma de Mallorca, Spain
| | - Brian T Tsuji
- School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Craig R Rayner
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), Parkville, Victoria 3052, Australia.,d3 medicine LLC, Parsippany, NJ, USA
| | - Roger L Nation
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), Parkville, Victoria 3052, Australia
| | - Cornelia B Landersdorfer
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), Parkville, Victoria 3052, Australia .,School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA
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42
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Hernando-Amado S, Blanco P, Alcalde-Rico M, Corona F, Reales-Calderón JA, Sánchez MB, Martínez JL. Multidrug efflux pumps as main players in intrinsic and acquired resistance to antimicrobials. Drug Resist Updat 2016; 28:13-27. [PMID: 27620952 DOI: 10.1016/j.drup.2016.06.007] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 05/31/2016] [Accepted: 06/23/2016] [Indexed: 12/31/2022]
Abstract
Multidrug efflux pumps constitute a group of transporters that are ubiquitously found in any organism. In addition to other functions with relevance for the cell physiology, efflux pumps contribute to the resistance to compounds used for treating different diseases, including resistance to anticancer drugs, antibiotics or antifungal compounds. In the case of antimicrobials, efflux pumps are major players in both intrinsic and acquired resistance to drugs currently in use for the treatment of infectious diseases. One important aspect not fully explored of efflux pumps consists on the identification of effectors able to induce their expression. Indeed, whereas the analysis of clinical isolates have shown that mutants overexpressing these resistance elements are frequently found, less is known on the conditions that may trigger expression of efflux pumps, hence leading to transient induction of resistance in vivo, a situation that is barely detectable using classical susceptibility tests. In the current article we review the structure and mechanisms of regulation of the expression of bacterial and fungal efflux pumps, with a particular focus in those for which a role in clinically relevant resistance has been reported.
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Affiliation(s)
- Sara Hernando-Amado
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Paula Blanco
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Manuel Alcalde-Rico
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Fernando Corona
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Jose A Reales-Calderón
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - María B Sánchez
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - José L Martínez
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain.
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43
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Krause KM, Serio AW, Kane TR, Connolly LE. Aminoglycosides: An Overview. Cold Spring Harb Perspect Med 2016; 6:6/6/a027029. [PMID: 27252397 DOI: 10.1101/cshperspect.a027029] [Citation(s) in RCA: 511] [Impact Index Per Article: 63.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Aminoglycosides are natural or semisynthetic antibiotics derived from actinomycetes. They were among the first antibiotics to be introduced for routine clinical use and several examples have been approved for use in humans. They found widespread use as first-line agents in the early days of antimicrobial chemotherapy, but were eventually replaced in the 1980s with cephalosporins, carbapenems, and fluoroquinolones. Aminoglycosides synergize with a variety of other antibacterial classes, which, in combination with the continued increase in the rise of multidrug-resistant bacteria and the potential to improve the safety and efficacy of the class through optimized dosing regimens, has led to a renewed interest in these broad-spectrum and rapidly bactericidal antibacterials.
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Affiliation(s)
| | | | | | - Lynn E Connolly
- Achaogen, South San Francisco, California 94080 Department of Medicine, Division of Infectious Diseases, University of California, San Francisco, San Francisco, California 94143
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44
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Potentiation of Aminoglycoside Activity in Pseudomonas aeruginosa by Targeting the AmgRS Envelope Stress-Responsive Two-Component System. Antimicrob Agents Chemother 2016; 60:3509-18. [PMID: 27021319 DOI: 10.1128/aac.03069-15] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 03/17/2016] [Indexed: 02/06/2023] Open
Abstract
A screen for agents that potentiated the activity of paromomycin (PAR), a 4,5-linked aminoglycoside (AG), against wild-type Pseudomonas aeruginosa identified the RNA polymerase inhibitor rifampin (RIF). RIF potentiated additional 4,5-linked AGs, such as neomycin and ribostamycin, but not the clinically important 4,6-linked AGs amikacin and gentamicin. Potentiation was absent in a mutant lacking the AmgRS envelope stress response two-component system (TCS), which protects the organism from AG-generated membrane-damaging aberrant polypeptides and, thus, promotes AG resistance, an indication that RIF was acting via this TCS in potentiating 4,5-linked AG activity. Potentiation was also absent in a RIF-resistant RNA polymerase mutant, consistent with its potentiation of AG activity being dependent on RNA polymerase perturbation. PAR-inducible expression of the AmgRS-dependent genes htpX and yccA was reduced by RIF, suggesting that AG activation of this TCS was compromised by this agent. Still, RIF did not compromise the membrane-protective activity of AmgRS, an indication that it impacted some other function of this TCS. RIF potentiated the activities of 4,5-linked AGs against several AG-resistant clinical isolates, in two cases also potentiating the activity of the 4,6-linked AGs. These cases were, in one instance, explained by an observed AmgRS-dependent expression of the MexXY multidrug efflux system, which accommodates a range of AGs, with RIF targeting of AmgRS undermining mexXY expression and its promotion of resistance to 4,5- and 4,6-linked AGs. Given this link between AmgRS, MexXY expression, and pan-AG resistance in P. aeruginosa, RIF might be a useful adjuvant in the AG treatment of P. aeruginosa infections.
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45
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Evolved resistance to colistin and its loss due to genetic reversion in Pseudomonas aeruginosa. Sci Rep 2016; 6:25543. [PMID: 27150578 PMCID: PMC4858706 DOI: 10.1038/srep25543] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 04/20/2016] [Indexed: 11/17/2022] Open
Abstract
The increased reliance on colistin for treating multidrug-resistant Gram-negative bacterial infections has resulted in the emergence of colistin-resistant Pseudomonas aeruginosa. We attempted to identify genetic contributors to colistin resistance in vitro evolved isogenic colistin-resistant and -susceptible strains of two P. aeruginosa lineages (P5 and P155). Their evolutionary paths to acquisition and loss of colistin resistance were also tracked. Comparative genomic analysis revealed 13 and five colistin resistance determinants in the P5 and P155 lineages, respectively. Lipid A in colistin-resistant mutants was modified through the addition of 4-amino-L-arabinose; this modification was absent in colistin-susceptible revertant strains. Many amino acid substitutions that emerged during the acquisition of colistin resistance were reversed in colistin-susceptible revertants. We demonstrated that evolved colistin resistance in P. aeruginosa was mediated by a complicated regulatory network that likely emerges through diverse genetic alterations. Colistin-resistant P. aeruginosa became susceptible to the colistin upon its withdrawal because of genetic reversion. The mechanisms through which P. aeruginosa acquires and loses colistin resistance have implications on the treatment options that can be applied against P. aeruginosa infections, with respect to improving bactericidal efficacy and preventing further resistance to antibiotics.
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46
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Teixeira B, Rodulfo H, Carreño N, Guzmán M, Salazar E, De Donato M. AMINOGLYCOSIDE RESISTANCE GENES IN Pseudomonas aeruginosa ISOLATES FROM CUMANA, VENEZUELA. Rev Inst Med Trop Sao Paulo 2016; 58:13. [PMID: 27007556 PMCID: PMC4804550 DOI: 10.1590/s1678-9946201658013] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 09/14/2015] [Indexed: 11/18/2022] Open
Abstract
The enzymatic modification of aminoglycosides by aminoglycoside-acetyltransferases
(AAC), aminoglycoside-adenyltransferases (AAD), and
aminoglycoside-phosphotransferases (APH), is the most common resistance mechanism in
P. aeruginosa and these enzymes can be coded on
mobile genetic elements that contribute to their dispersion. One hundred and thirty
seven P. aeruginosa isolates from the University Hospital, Cumana,
Venezuela (HUAPA) were evaluated. Antimicrobial susceptibility was determined by the
disk diffusion method and theaac, aadB and
aph genes were detected by PCR. Most of the P.
aeruginosa isolates (33/137) were identified from the Intensive Care Unit
(ICU), mainly from discharges (96/137). The frequency of resistant P.
aeruginosaisolates was found to be higher for the aminoglycosides
tobramycin and amikacin (30.7 and 29.9%, respectively). Phenotype VI, resistant to
these antibiotics, was the most frequent (14/49), followed by phenotype I, resistant
to all the aminoglycosides tested (12/49). The
aac(6´)-Ib,aphA1 and aadB genes
were the most frequently detected, and the simultaneous presence of several
resistance genes in the same isolate was demonstrated. Aminoglycoside resistance in
isolates ofP. aeruginosa at the HUAPA is partly due to the presence
of the aac(6´)-Ib, aphA1 andaadB
genes, but the high rates of antimicrobial resistance suggest the existence of
several mechanisms acting together. This is the first report of aminoglycoside
resistance genes in Venezuela and one of the few in Latin America.
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Affiliation(s)
| | - Hectorina Rodulfo
- Lab. Genética Molecular, Universidad de Oriente, Cumaná, Venezuela, , , ,
| | - Numirin Carreño
- Lab. Genética Molecular, Universidad de Oriente, Cumaná, Venezuela, , , ,
| | - Militza Guzmán
- Lab. de Bacteriología Molecular, Dpto. Bioanálisis, Universidad de Oriente, Cumaná, Venezuela, ,
| | - Elsa Salazar
- Lab. de Bacteriología Molecular, Dpto. Bioanálisis, Universidad de Oriente, Cumaná, Venezuela, ,
| | - Marcos De Donato
- Lab. Genética Molecular, Universidad de Oriente, Cumaná, Venezuela, , , ,
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47
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Jacobs M, Grégoire N, Couet W, Bulitta JB. Distinguishing Antimicrobial Models with Different Resistance Mechanisms via Population Pharmacodynamic Modeling. PLoS Comput Biol 2016; 12:e1004782. [PMID: 26967893 PMCID: PMC4788427 DOI: 10.1371/journal.pcbi.1004782] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 02/01/2016] [Indexed: 12/02/2022] Open
Abstract
Semi-mechanistic pharmacokinetic-pharmacodynamic (PK-PD) modeling is increasingly used for antimicrobial drug development and optimization of dosage regimens, but systematic simulation-estimation studies to distinguish between competing PD models are lacking. This study compared the ability of static and dynamic in vitro infection models to distinguish between models with different resistance mechanisms and support accurate and precise parameter estimation. Monte Carlo simulations (MCS) were performed for models with one susceptible bacterial population without (M1) or with a resting stage (M2), a one population model with adaptive resistance (M5), models with pre-existing susceptible and resistant populations without (M3) or with (M4) inter-conversion, and a model with two pre-existing populations with adaptive resistance (M6). For each model, 200 datasets of the total bacterial population were simulated over 24h using static antibiotic concentrations (256-fold concentration range) or over 48h under dynamic conditions (dosing every 12h; elimination half-life: 1h). Twelve-hundred random datasets (each containing 20 curves for static or four curves for dynamic conditions) were generated by bootstrapping. Each dataset was estimated by all six models via population PD modeling to compare bias and precision. For M1 and M3, most parameter estimates were unbiased (<10%) and had good imprecision (<30%). However, parameters for adaptive resistance and inter-conversion for M2, M4, M5 and M6 had poor bias and large imprecision under static and dynamic conditions. For datasets that only contained viable counts of the total population, common statistical criteria and diagnostic plots did not support sound identification of the true resistance mechanism. Therefore, it seems advisable to quantify resistant bacteria and characterize their MICs and resistance mechanisms to support extended simulations and translate from in vitro experiments to animal infection models and ultimately patients. Mathematical models are increasingly used for analysis and interpretation of in vitro efficacy results of antimicrobial drugs. Various models are employed in the scientific literature and it seems that they are equally able to describe the observed data. The aim of the present study was to compare different models in various experimental designs and with different resistance mechanisms of bacteria. For that purpose we have generated experimental data through Monte-Carlo simulations and then used six different mathematical models to analyze these results. We showed that statistical comparison of models did not allow determining which was the true mechanism of resistance, i.e. the one used for the simulation step. Moreover mathematical parameters for bacterial resistance were estimated with bias and with a low precision except for the simpler cases. This suggests that the choice of the mathematical model for data analysis should be guided by experimental characterization of the bacterial mechanism of resistance.
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Affiliation(s)
| | | | | | - Jurgen B. Bulitta
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, Florida, United States of America
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48
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Wu X, Held K, Zheng C, Staudinger BJ, Chavez JD, Weisbrod CR, Eng JK, Singh PK, Manoil C, Bruce JE. Dynamic Proteome Response of Pseudomonas aeruginosa to Tobramycin Antibiotic Treatment. Mol Cell Proteomics 2015; 14:2126-37. [PMID: 26018413 DOI: 10.1074/mcp.m115.050161] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Indexed: 11/06/2022] Open
Abstract
Genetically susceptible bacteria become antibiotic tolerant during chronic infections, and the mechanisms responsible are poorly understood. One factor that may contribute to differential sensitivity in vitro and in vivo is differences in the time-dependent tobramycin concentration profile experienced by the bacteria. Here, we examine the proteome response induced by subinhibitory concentrations of tobramycin in Pseudomonas aeruginosa cells grown under planktonic conditions. These efforts revealed increased levels of heat shock proteins and proteases were present at higher dosage treatments (0.5 and 1 μg/ml), while less dramatic at 0.1 μg/ml dosage. In contrast, many metabolic enzymes were significantly induced by lower dosages (0.1 and 0.5 μg/ml) but not at 1 μg/ml dosage. Time course proteome analysis further revealed that the increase of heat shock proteins and proteases was most rapid from 15 min to 60 min, and the increased levels sustained till 6 h (last time point tested). Heat shock protein IbpA exhibited the greatest induction by tobramycin, up to 90-fold. Nevertheless, deletion of ibpA did not enhance sensitivity to tobramycin. It seemed possible that the absence of sensitization could be due to redundant functioning of IbpA with other proteins that protect cells from tobramycin. Indeed, inactivation of two heat shock chaperones/proteases in addition to ibpA in double mutants (ibpA/clpB, ibpA/PA0779 and ibpA/hslV) did increase tobramycin sensitivity. Collectively, these results demonstrate the time- and concentration-dependent nature of the P. aeruginosa proteome response to tobramycin and that proteome modulation and protein redundancy are protective mechanisms to help bacteria resist antibiotic treatments.
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Affiliation(s)
- Xia Wu
- From the ‡Department of Genome Sciences
| | | | | | - Benjamin J Staudinger
- ¶Department of Medicine and Microbiology, University of Washington, Seattle, WA 98195
| | | | | | | | - Pradeep K Singh
- ¶Department of Medicine and Microbiology, University of Washington, Seattle, WA 98195
| | | | - James E Bruce
- From the ‡Department of Genome Sciences, §Department of Chemistry,
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49
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Sodium nitrite blocks the activity of aminoglycosides against Pseudomonas aeruginosa biofilms. Antimicrob Agents Chemother 2015; 59:3329-34. [PMID: 25801569 DOI: 10.1128/aac.00546-15] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 03/17/2015] [Indexed: 12/26/2022] Open
Abstract
Sodium nitrite has broad antimicrobial activity at pH 6.5, including the ability to prevent biofilm growth by Pseudomonas aeruginosa on the surfaces of airway epithelial cells. Because of its antimicrobial activity, nitrite is being investigated as an inhaled agent for chronic P. aeruginosa airway infections in cystic fibrosis patients. However, the interaction between nitrite and commonly used aminoglycosides is unknown. This paper investigates the interaction between nitrite and tobramycin in liquid culture, abiotic biofilms, and a biotic biofilm model simulating the conditions in the cystic fibrosis airway. The addition of nitrite prevented killing by aminoglycosides in liquid culture, with dose dependence between 1.5 and 15 mM. The effect was not blocked by the nitric oxide scavenger CPTIO or dependent on efflux pump activity. Nitrite shifted the biofilm minimal bactericidal concentration (MBC-biofilm) from 256 μg/ml to >1,024 μg/ml in an abiotic biofilm model. In a biotic biofilm model, the addition of 50 mM nitrite decreased the antibiofilm activity of tobramycin by up to 1.2 log. Respiratory chain inhibition recapitulated the inhibition of aminoglycoside activity by nitrite, suggesting a potential mechanism of inhibition of energy-dependent aminoglycoside uptake. In summary, sodium nitrite induces resistance to both gentamicin and tobramycin in P. aeruginosa grown in liquid culture, as an abiotic biofilm, or as a biotic biofilm.
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50
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Two mechanisms of killing of Pseudomonas aeruginosa by tobramycin assessed at multiple inocula via mechanism-based modeling. Antimicrob Agents Chemother 2015; 59:2315-27. [PMID: 25645838 DOI: 10.1128/aac.04099-14] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial resistance is among the most serious threats to human health globally, and many bacterial isolates have emerged that are resistant to all antibiotics in monotherapy. Aminoglycosides are often used in combination therapies against severe infections by multidrug-resistant bacteria. However, models quantifying different antibacterial effects of aminoglycosides are lacking. While the mode of aminoglycoside action on protein synthesis has often been studied, their disruptive action on the outer membrane of Gram-negative bacteria remains poorly characterized. Here, we developed a novel quantitative model for these two mechanisms of aminoglycoside action, phenotypic tolerance at high bacterial densities, and adaptive bacterial resistance in response to an aminoglycoside (tobramycin) against three Pseudomonas aeruginosa strains. At low-intermediate tobramycin concentrations (<4 mg/liter), bacterial killing due to the effect on protein synthesis was most important, whereas disruption of the outer membrane was the predominant killing mechanism at higher tobramycin concentrations (≥8 mg/liter). The extent of killing was comparable across all inocula; however, the rate of bacterial killing and growth was substantially lower at the 10(8.9) CFU/ml inoculum than that at the lower inocula. At 1 to 4 mg/liter tobramycin for strain PAO1-RH, there was a 0.5- to 6-h lag time of killing that was modeled via the time to synthesize hypothetical lethal protein(s). Disruption of the outer bacterial membrane by tobramycin may be critical to enhance the target site penetration of antibiotics used in synergistic combinations with aminoglycosides and thereby combat multidrug-resistant bacteria. The two mechanisms of aminoglycoside action and the new quantitative model hold great promise to rationally design novel, synergistic aminoglycoside combination dosage regimens.
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