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Li H, E W, Zhao D, Liu H, Pei J, Du B, Liu K, Zhu X, Wang C. Response of Paenibacillus polymyxa SC2 to the stress of polymyxin B and a key ABC transporter YwjA involved. Appl Microbiol Biotechnol 2024; 108:17. [PMID: 38170316 DOI: 10.1007/s00253-023-12916-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 09/24/2023] [Accepted: 10/04/2023] [Indexed: 01/05/2024]
Abstract
Polymyxins are cationic peptide antibiotics and regarded as the "final line of defense" against multidrug-resistant bacterial infections. Meanwhile, some polymyxin-resistant strains and the corresponding resistance mechanisms have also been reported. However, the response of the polymyxin-producing strain Paenibacillus polymyxa to polymyxin stress remains unclear. The purpose of this study was to investigate the stress response of gram-positive P. polymyxa SC2 to polymyxin B and to identify functional genes involved in the stress response process. Polymyxin B treatment upregulated the expression of genes related to basal metabolism, transcriptional regulation, transport, and flagella formation and increased intracellular ROS levels, flagellar motility, and biofilm formation in P. polymyxa SC2. Adding magnesium, calcium, and iron alleviated the stress of polymyxin B on P. polymyxa SC2, furthermore, magnesium and calcium could improve the resistance of P. polymyxa SC2 to polymyxin B by promoting biofilm formation. Meanwhile, functional identification of differentially expressed genes indicated that an ABC superfamily transporter YwjA was involved in the stress response to polymyxin B of P. polymyxa SC2. This study provides an important reference for improving the resistance of P. polymyxa to polymyxins and increasing the yield of polymyxins. KEY POINTS: • Phenotypic responses of P. polymyxa to polymyxin B was performed and indicated by RNA-seq • Forming biofilm was a key strategy of P. polymyxa to alleviate polymyxin stress • ABC transporter YwjA was involved in the stress resistance of P. polymyxa to polymyxin B.
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Affiliation(s)
- Hui Li
- College of Life Sciences, National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, Shandong Engineering Research Center of Plant-Microbia Restoration for Saline-Alkali Land, Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018, China
| | - Wenhui E
- College of Life Sciences, National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, Shandong Engineering Research Center of Plant-Microbia Restoration for Saline-Alkali Land, Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018, China
| | - Dongying Zhao
- College of Life Sciences, National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, Shandong Engineering Research Center of Plant-Microbia Restoration for Saline-Alkali Land, Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018, China
| | - Haiyang Liu
- College of Life Sciences, National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, Shandong Engineering Research Center of Plant-Microbia Restoration for Saline-Alkali Land, Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018, China
| | - Jian Pei
- College of Life Sciences, National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, Shandong Engineering Research Center of Plant-Microbia Restoration for Saline-Alkali Land, Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018, China
| | - Binghai Du
- College of Life Sciences, National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, Shandong Engineering Research Center of Plant-Microbia Restoration for Saline-Alkali Land, Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018, China
| | - Kai Liu
- College of Life Sciences, National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, Shandong Engineering Research Center of Plant-Microbia Restoration for Saline-Alkali Land, Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018, China
| | - Xueming Zhu
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Chengqiang Wang
- College of Life Sciences, National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, Shandong Engineering Research Center of Plant-Microbia Restoration for Saline-Alkali Land, Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018, China.
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2
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Antunes B, Zanchi C, Johnston PR, Maron B, Witzany C, Regoes RR, Hayouka Z, Rolff J. The evolution of antimicrobial peptide resistance in Pseudomonas aeruginosa is severely constrained by random peptide mixtures. PLoS Biol 2024; 22:e3002692. [PMID: 38954678 PMCID: PMC11218975 DOI: 10.1371/journal.pbio.3002692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 05/28/2024] [Indexed: 07/04/2024] Open
Abstract
The prevalence of antibiotic-resistant pathogens has become a major threat to public health, requiring swift initiatives for discovering new strategies to control bacterial infections. Hence, antibiotic stewardship and rapid diagnostics, but also the development, and prudent use, of novel effective antimicrobial agents are paramount. Ideally, these agents should be less likely to select for resistance in pathogens than currently available conventional antimicrobials. The usage of antimicrobial peptides (AMPs), key components of the innate immune response, and combination therapies, have been proposed as strategies to diminish the emergence of resistance. Herein, we investigated whether newly developed random antimicrobial peptide mixtures (RPMs) can significantly reduce the risk of resistance evolution in vitro to that of single sequence AMPs, using the ESKAPE pathogen Pseudomonas aeruginosa (P. aeruginosa) as a model gram-negative bacterium. Infections of this pathogen are difficult to treat due the inherent resistance to many drug classes, enhanced by the capacity to form biofilms. P. aeruginosa was experimentally evolved in the presence of AMPs or RPMs, subsequentially assessing the extent of resistance evolution and cross-resistance/collateral sensitivity between treatments. Furthermore, the fitness costs of resistance on bacterial growth were studied and whole-genome sequencing used to investigate which mutations could be candidates for causing resistant phenotypes. Lastly, changes in the pharmacodynamics of the evolved bacterial strains were examined. Our findings suggest that using RPMs bears a much lower risk of resistance evolution compared to AMPs and mostly prevents cross-resistance development to other treatments, while maintaining (or even improving) drug sensitivity. This strengthens the case for using random cocktails of AMPs in favour of single AMPs, against which resistance evolved in vitro, providing an alternative to classic antibiotics worth pursuing.
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Affiliation(s)
- Bernardo Antunes
- Freie Universität Berlin, Evolutionary Biology, Berlin, Germany
- Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Caroline Zanchi
- Freie Universität Berlin, Evolutionary Biology, Berlin, Germany
| | - Paul R. Johnston
- Freie Universität Berlin, Evolutionary Biology, Berlin, Germany
- Berlin Centre for Genomics in Biodiversity Research, Berlin, Germany
- University of St. Andrews, School of Medicine, North Haugh, St Andrews, Fife, United Kingdom
| | - Bar Maron
- Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot, Israel
| | | | - Roland R. Regoes
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
| | - Zvi Hayouka
- Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Jens Rolff
- Freie Universität Berlin, Evolutionary Biology, Berlin, Germany
- Berlin Centre for Genomics in Biodiversity Research, Berlin, Germany
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3
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Hsieh YYP, Sun W, Young JM, Cheung R, Hogan DA, Dandekar AA, Malik HS. Widespread fungal-bacterial competition for magnesium lowers bacterial susceptibility to polymyxin antibiotics. PLoS Biol 2024; 22:e3002694. [PMID: 38900845 PMCID: PMC11218974 DOI: 10.1371/journal.pbio.3002694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 07/02/2024] [Accepted: 05/29/2024] [Indexed: 06/22/2024] Open
Abstract
Fungi and bacteria coexist in many polymicrobial communities, yet the molecular basis of their interactions remains poorly understood. Here, we show that the fungus Candida albicans sequesters essential magnesium ions from the bacterium Pseudomonas aeruginosa. To counteract fungal Mg2+ sequestration, P. aeruginosa expresses the Mg2+ transporter MgtA when Mg2+ levels are low. Thus, loss of MgtA specifically impairs P. aeruginosa in co-culture with C. albicans, but fitness can be restored by supplementing Mg2+. Using a panel of fungi and bacteria, we show that Mg2+ sequestration is a general mechanism of fungal antagonism against gram-negative bacteria. Mg2+ limitation enhances bacterial resistance to polymyxin antibiotics like colistin, which target gram-negative bacterial membranes. Indeed, experimental evolution reveals that P. aeruginosa evolves C. albicans-dependent colistin resistance via non-canonical means; antifungal treatment renders resistant bacteria colistin-sensitive. Our work suggests that fungal-bacterial competition could profoundly impact polymicrobial infection treatment with antibiotics of last resort.
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Affiliation(s)
- Yu-Ying Phoebe Hsieh
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Wanting Sun
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Janet M. Young
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Robin Cheung
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Deborah A. Hogan
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Ajai A. Dandekar
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Harmit S. Malik
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
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4
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Padhy I, Dwibedy SK, Mohapatra SS. A molecular overview of the polymyxin-LPS interaction in the context of its mode of action and resistance development. Microbiol Res 2024; 283:127679. [PMID: 38508087 DOI: 10.1016/j.micres.2024.127679] [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: 07/31/2023] [Revised: 03/03/2024] [Accepted: 03/06/2024] [Indexed: 03/22/2024]
Abstract
With the rising incidences of antimicrobial resistance (AMR) and the diminishing options of novel antimicrobial agents, it is paramount to decipher the molecular mechanisms of action and the emergence of resistance to the existing drugs. Polymyxin, a cationic antimicrobial lipopeptide, is used to treat infections by Gram-negative bacterial pathogens as a last option. Though polymyxins were identified almost seventy years back, their use has been restricted owing to toxicity issues in humans. However, their clinical use has been increasing in recent times resulting in the rise of polymyxin resistance. Moreover, the detection of "mobile colistin resistance (mcr)" genes in the environment and their spread across the globe have complicated the scenario. The mechanism of polymyxin action and the development of resistance is not thoroughly understood. Specifically, the polymyxin-bacterial lipopolysaccharide (LPS) interaction is a challenging area of investigation. The use of advanced biophysical techniques and improvement in molecular dynamics simulation approaches have furthered our understanding of this interaction, which will help develop polymyxin analogs with better bactericidal effects and lesser toxicity in the future. In this review, we have delved deeper into the mechanisms of polymyxin-LPS interactions, highlighting several models proposed, and the mechanisms of polymyxin resistance development in some of the most critical Gram-negative pathogens.
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Affiliation(s)
- Indira Padhy
- Molecular Microbiology Lab, Department of Biotechnology, Berhampur University, Bhanja Bihar, Berhampur 760007, Odisha, India
| | - Sambit K Dwibedy
- Molecular Microbiology Lab, Department of Biotechnology, Berhampur University, Bhanja Bihar, Berhampur 760007, Odisha, India
| | - Saswat S Mohapatra
- Molecular Microbiology Lab, Department of Biotechnology, Berhampur University, Bhanja Bihar, Berhampur 760007, Odisha, India.
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5
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Wu W, Huang J, Xu Z. Antibiotic influx and efflux in Pseudomonas aeruginosa: Regulation and therapeutic implications. Microb Biotechnol 2024; 17:e14487. [PMID: 38801351 PMCID: PMC11129675 DOI: 10.1111/1751-7915.14487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 05/06/2024] [Accepted: 05/09/2024] [Indexed: 05/29/2024] Open
Abstract
Pseudomonas aeruginosa is a notorious multidrug-resistant pathogen that poses a serious and growing threat to the worldwide public health. The expression of resistance determinants is exquisitely modulated by the abundant regulatory proteins and the intricate signal sensing and transduction systems in this pathogen. Downregulation of antibiotic influx porin proteins and upregulation of antibiotic efflux pump systems owing to mutational changes in their regulators or the presence of distinct inducing molecular signals represent two of the most efficient mechanisms that restrict intracellular antibiotic accumulation and enable P. aeruginosa to resist multiple antibiotics. Treatment of P. aeruginosa infections is extremely challenging due to the highly inducible mechanism of antibiotic resistance. This review comprehensively summarizes the regulatory networks of the major porin proteins (OprD and OprH) and efflux pumps (MexAB-OprM, MexCD-OprJ, MexEF-OprN, and MexXY) that play critical roles in antibiotic influx and efflux in P. aeruginosa. It also discusses promising therapeutic approaches using safe and efficient adjuvants to enhance the efficacy of conventional antibiotics to combat multidrug-resistant P. aeruginosa by controlling the expression levels of porins and efflux pumps. This review not only highlights the complexity of the regulatory network that induces antibiotic resistance in P. aeruginosa but also provides important therapeutic implications in targeting the inducible mechanism of resistance.
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Affiliation(s)
- Weiyan Wu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research CentreSouth China Agricultural UniversityGuangzhouChina
| | - Jiahui Huang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research CentreSouth China Agricultural UniversityGuangzhouChina
| | - Zeling Xu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research CentreSouth China Agricultural UniversityGuangzhouChina
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6
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Baltogianni M, Dermitzaki N, Kosmeri C, Serbis A, Balomenou F, Giapros V. Reintroduction of Legacy Antibiotics in Neonatal Sepsis: The Special Role of Fosfomycin and Colistin. Antibiotics (Basel) 2024; 13:333. [PMID: 38667009 PMCID: PMC11047481 DOI: 10.3390/antibiotics13040333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 04/03/2024] [Accepted: 04/04/2024] [Indexed: 04/29/2024] Open
Abstract
Neonatal sepsis is a leading cause of morbidity and mortality in neonates, particularly in low- and middle-income countries. The emergence of antimicrobial resistance is a rapidly growing global problem. A significant proportion of the pathogens that commonly cause neonatal sepsis are resistant to multiple antibiotics. Therefore, for the empirical treatment of neonatal sepsis, the repurposing of older antibiotics that are effective against multidrug-resistant pathogens is being investigated. This review aims to provide an overview of current research and experience using the repurposed antibiotics colistin and fosfomycin for the empirical treatment of neonatal sepsis. Based on current knowledge, colistin and fosfomycin may be potentially helpful for the empirical treatment of sepsis in neonates due to their efficacy against a wide range of pathogens and acceptable safety profile.
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Affiliation(s)
- Maria Baltogianni
- Neonatal Intensive Care Unit, School of Medicine, University of Ioannina, 451 10 Ioannina, Greece; (M.B.); (N.D.); (F.B.)
| | - Niki Dermitzaki
- Neonatal Intensive Care Unit, School of Medicine, University of Ioannina, 451 10 Ioannina, Greece; (M.B.); (N.D.); (F.B.)
| | - Chrysoula Kosmeri
- Department of Paediatrics, School of Medicine, University of Ioannina, 451 10 Ioannina, Greece; (C.K.); (A.S.)
| | - Anastasios Serbis
- Department of Paediatrics, School of Medicine, University of Ioannina, 451 10 Ioannina, Greece; (C.K.); (A.S.)
| | - Foteini Balomenou
- Neonatal Intensive Care Unit, School of Medicine, University of Ioannina, 451 10 Ioannina, Greece; (M.B.); (N.D.); (F.B.)
| | - Vasileios Giapros
- Neonatal Intensive Care Unit, School of Medicine, University of Ioannina, 451 10 Ioannina, Greece; (M.B.); (N.D.); (F.B.)
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7
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Lang M, Carvalho A, Baharoglu Z, Mazel D. Aminoglycoside uptake, stress, and potentiation in Gram-negative bacteria: new therapies with old molecules. Microbiol Mol Biol Rev 2023; 87:e0003622. [PMID: 38047635 PMCID: PMC10732077 DOI: 10.1128/mmbr.00036-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023] Open
Abstract
SUMMARYAminoglycosides (AGs) are long-known molecules successfully used against Gram-negative pathogens. While their use declined with the discovery of new antibiotics, they are now classified as critically important molecules because of their effectiveness against multidrug-resistant bacteria. While they can efficiently cross the Gram-negative envelope, the mechanism of AG entry is still incompletely understood, although this comprehension is essential for the development of new therapies in the face of the alarming increase in antibiotic resistance. Increasing antibiotic uptake in bacteria is one strategy to enhance effective treatments. This review aims, first, to consolidate old and recent knowledge about AG uptake; second, to explore the connection between AG-dependent bacterial stress and drug uptake; and finally, to present new strategies of potentiation of AG uptake for more efficient antibiotic therapies. In particular, we emphasize on the connection between sugar transport and AG potentiation.
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Affiliation(s)
- Manon Lang
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, Paris, France
| | - André Carvalho
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, Paris, France
| | - Zeynep Baharoglu
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, Paris, France
| | - Didier Mazel
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, Paris, France
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8
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Giovagnorio F, De Vito A, Madeddu G, Parisi SG, Geremia N. Resistance in Pseudomonas aeruginosa: A Narrative Review of Antibiogram Interpretation and Emerging Treatments. Antibiotics (Basel) 2023; 12:1621. [PMID: 37998823 PMCID: PMC10669487 DOI: 10.3390/antibiotics12111621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 11/02/2023] [Accepted: 11/10/2023] [Indexed: 11/25/2023] Open
Abstract
Pseudomonas aeruginosa is a ubiquitous Gram-negative bacterium renowned for its resilience and adaptability across diverse environments, including clinical settings, where it emerges as a formidable pathogen. Notorious for causing nosocomial infections, P. aeruginosa presents a significant challenge due to its intrinsic and acquired resistance mechanisms. This comprehensive review aims to delve into the intricate resistance mechanisms employed by P. aeruginosa and to discern how these mechanisms can be inferred by analyzing sensitivity patterns displayed in antibiograms, emphasizing the complexities encountered in clinical management. Traditional monotherapies are increasingly overshadowed by the emergence of multidrug-resistant strains, necessitating a paradigm shift towards innovative combination therapies and the exploration of novel antibiotics. The review accentuates the critical role of accurate antibiogram interpretation in guiding judicious antibiotic use, optimizing therapeutic outcomes, and mitigating the propagation of antibiotic resistance. Misinterpretations, it cautions, can inadvertently foster resistance, jeopardizing patient health and amplifying global antibiotic resistance challenges. This paper advocates for enhanced clinician proficiency in interpreting antibiograms, facilitating informed and strategic antibiotic deployment, thereby improving patient prognosis and contributing to global antibiotic stewardship efforts.
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Affiliation(s)
- Federico Giovagnorio
- Department of Molecular Medicine, University of Padua, 35121 Padua, Italy; (F.G.); (S.G.P.)
| | - Andrea De Vito
- Unit of Infectious Diseases, Department of Medicine, Surgery and Pharmacy, University of Sassari, 07100 Sassari, Italy;
| | - Giordano Madeddu
- Unit of Infectious Diseases, Department of Medicine, Surgery and Pharmacy, University of Sassari, 07100 Sassari, Italy;
| | | | - Nicholas Geremia
- Unit of Infectious Diseases, Department of Clinical Medicine, Ospedale “dell’Angelo”, 30174 Venice, Italy
- Unit of Infectious Diseases, Department of Clinical Medicine, Ospedale Civile “S.S. Giovanni e Paolo”, 30122 Venice, Italy
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9
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Verdial C, Serrano I, Tavares L, Gil S, Oliveira M. Mechanisms of Antibiotic and Biocide Resistance That Contribute to Pseudomonas aeruginosa Persistence in the Hospital Environment. Biomedicines 2023; 11:biomedicines11041221. [PMID: 37189839 DOI: 10.3390/biomedicines11041221] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 04/13/2023] [Accepted: 04/18/2023] [Indexed: 05/17/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic bacterial pathogen responsible for multiple hospital- and community-acquired infections, both in human and veterinary medicine. P. aeruginosa persistence in clinical settings is worrisome and is a result of its remarkable flexibility and adaptability. This species exhibits several characteristics that allow it to thrive under different environmental conditions, including the ability to colonize inert materials such as medical equipment and hospital surfaces. P. aeruginosa presents several intrinsic mechanisms of defense that allow it to survive external aggressions, but it is also able to develop strategies and evolve into multiple phenotypes to persevere, which include antimicrobial-tolerant strains, persister cells, and biofilms. Currently, these emergent pathogenic strains are a worldwide problem and a major concern. Biocides are frequently used as a complementary/combination strategy to control the dissemination of P. aeruginosa-resistant strains; however, tolerance to commonly used biocides has also already been reported, representing an impediment to the effective elimination of this important pathogen from clinical settings. This review focuses on the characteristics of P. aeruginosa responsible for its persistence in hospital environments, including those associated with its antibiotic and biocide resistance ability.
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Affiliation(s)
- Cláudia Verdial
- Gato Escondido-Veterinary Clinic, Av. Bombeiros Voluntários n°22B, 2950-209 Palmela, Portugal
| | - Isa Serrano
- CIISA-Center for Interdisciplinary Research in Animal Health, Faculty of Medicine, University of Lisbon, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1300-477 Lisboa, Portugal
| | - Luís Tavares
- CIISA-Center for Interdisciplinary Research in Animal Health, Faculty of Medicine, University of Lisbon, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1300-477 Lisboa, Portugal
| | - Solange Gil
- CIISA-Center for Interdisciplinary Research in Animal Health, Faculty of Medicine, University of Lisbon, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1300-477 Lisboa, Portugal
| | - Manuela Oliveira
- CIISA-Center for Interdisciplinary Research in Animal Health, Faculty of Medicine, University of Lisbon, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1300-477 Lisboa, Portugal
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10
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Bairoliya S, Goel A, Mukherjee M, Koh Zhi Xiang J, Cao B. Monochloramine Induces Release of DNA and RNA from Bacterial Cells: Quantification, Sequencing Analyses, and Implications. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:15791-15804. [PMID: 36215406 DOI: 10.1021/acs.est.2c06632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Monochloramine (MCA) is a widely used secondary disinfectant to suppress microbial growth in drinking water distribution systems. In monochloraminated drinking water, a significant amount of extracellular DNA (eDNA) has been reported, which has many implications ranging from obscuring DNA-based drinking water microbiome analyses to posing potential health concerns. To address this, it is imperative for us to know the origin of the eDNA in drinking water. Using Pseudomonas aeruginosa as a model organism, we report for the first time that MCA induces the release of nucleic acids from both biofilms and planktonic cells. Upon exposure to 2 mg/L MCA, massive release of DNA from suspended cells in both MilliQ water and 0.9% NaCl was directly visualized using live cell imaging in a CellASIC ONIX2 microfluidic system. Exposing established biofilms to MCA also resulted in DNA release from the biofilms, which was confirmed by increased detection of eDNA in the effluent. Intriguingly, massive release of RNA was also observed, and the extracellular RNA (eRNA) was also found to persist in water for days. Sequencing analyses of the eDNA revealed that it could be used to assemble the whole genome of the model organism, while in the water, certain fragments of the genome were more persistent than others. RNA sequencing showed that the eRNA contains non-coding RNA and mRNA, implying its role as a possible signaling molecule in environmental systems and a snapshot of the past metabolic state of the bacterial cells.
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Affiliation(s)
- Sakcham Bairoliya
- Singapore Centre for Environmental Life Sciences Engineering, Interdisciplinary Graduate Program, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Ave, Singapore 639798, Singapore
| | - Apoorva Goel
- Singapore Centre for Environmental Life Sciences Engineering, Interdisciplinary Graduate Program, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Manisha Mukherjee
- Singapore Centre for Environmental Life Sciences Engineering, Interdisciplinary Graduate Program, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Ave, Singapore 639798, Singapore
| | - Jonas Koh Zhi Xiang
- Singapore Centre for Environmental Life Sciences Engineering, Interdisciplinary Graduate Program, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Bin Cao
- Singapore Centre for Environmental Life Sciences Engineering, Interdisciplinary Graduate Program, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Ave, Singapore 639798, Singapore
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11
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Dulanto Chiang A, Patil PP, Beka L, Youn JH, Launay A, Bonomo RA, Khil PP, Dekker JP. Hypermutator strains of Pseudomonas aeruginosa reveal novel pathways of resistance to combinations of cephalosporin antibiotics and beta-lactamase inhibitors. PLoS Biol 2022; 20:e3001878. [PMID: 36399436 PMCID: PMC9718400 DOI: 10.1371/journal.pbio.3001878] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 12/02/2022] [Accepted: 10/13/2022] [Indexed: 11/19/2022] Open
Abstract
Hypermutation due to DNA mismatch repair (MMR) deficiencies can accelerate the development of antibiotic resistance in Pseudomonas aeruginosa. Whether hypermutators generate resistance through predominantly similar molecular mechanisms to wild-type (WT) strains is not fully understood. Here, we show that MMR-deficient P. aeruginosa can evolve resistance to important broad-spectrum cephalosporin/beta-lactamase inhibitor combination antibiotics through novel mechanisms not commonly observed in WT lineages. Using whole-genome sequencing (WGS) and transcriptional profiling of isolates that underwent in vitro adaptation to ceftazidime/avibactam (CZA), we characterized the detailed sequence of mutational and transcriptional changes underlying the development of resistance. Surprisingly, MMR-deficient lineages rapidly developed high-level resistance (>256 μg/mL) largely without corresponding fixed mutations or transcriptional changes in well-established resistance genes. Further investigation revealed that these isolates had paradoxically generated an early inactivating mutation in the mexB gene of the MexAB-OprM efflux pump, a primary mediator of CZA resistance in P. aeruginosa, potentially driving an evolutionary search for alternative resistance mechanisms. In addition to alterations in a number of genes not known to be associated with resistance, 2 mutations were observed in the operon encoding the RND efflux pump MexVW. These mutations resulted in a 4- to 6-fold increase in resistance to ceftazidime, CZA, cefepime, and ceftolozane-tazobactam when engineered into a WT strain, demonstrating a potentially important and previously unappreciated mechanism of resistance to these antibiotics in P. aeruginosa. Our results suggest that MMR-deficient isolates may rapidly evolve novel resistance mechanisms, sometimes with complex dynamics that reflect gene inactivation that occurs with hypermutation. The apparent ease with which hypermutators may switch to alternative resistance mechanisms for which antibiotics have not been developed may carry important clinical implications.
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Affiliation(s)
- Augusto Dulanto Chiang
- Bacterial Pathogenesis and Antimicrobial Resistance Unit, LCIM, NIAID, NIH, Bethesda, Maryland, United States of America
| | - Prashant P. Patil
- Bacterial Pathogenesis and Antimicrobial Resistance Unit, LCIM, NIAID, NIH, Bethesda, Maryland, United States of America
| | - Lidia Beka
- Bacterial Pathogenesis and Antimicrobial Resistance Unit, LCIM, NIAID, NIH, Bethesda, Maryland, United States of America
| | - Jung-Ho Youn
- Dept. Laboratory Medicine, NIH Clinical Center, NIH, Bethesda, Maryland, United States of America
| | - Adrien Launay
- Bacterial Pathogenesis and Antimicrobial Resistance Unit, LCIM, NIAID, NIH, Bethesda, Maryland, United States of America
| | - Robert A. Bonomo
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, United States of America
- Departments of Pharmacology, Molecular Biology and Microbiology, Biochemistry, and Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES) Cleveland, Ohio, United States of America
| | - Pavel P. Khil
- Bacterial Pathogenesis and Antimicrobial Resistance Unit, LCIM, NIAID, NIH, Bethesda, Maryland, United States of America
- Dept. Laboratory Medicine, NIH Clinical Center, NIH, Bethesda, Maryland, United States of America
| | - John P. Dekker
- Bacterial Pathogenesis and Antimicrobial Resistance Unit, LCIM, NIAID, NIH, Bethesda, Maryland, United States of America
- Dept. Laboratory Medicine, NIH Clinical Center, NIH, Bethesda, Maryland, United States of America
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12
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Mahamad Maifiah MH, Zhu Y, Tsuji BT, Creek DJ, Velkov T, Li J. Integrated metabolomic and transcriptomic analyses of the synergistic effect of polymyxin-rifampicin combination against Pseudomonas aeruginosa. J Biomed Sci 2022; 29:89. [PMID: 36310165 PMCID: PMC9618192 DOI: 10.1186/s12929-022-00874-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 10/21/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Understanding the mechanism of antimicrobial action is critical for improving antibiotic therapy. For the first time, we integrated correlative metabolomics and transcriptomics of Pseudomonas aeruginosa to elucidate the mechanism of synergistic killing of polymyxin-rifampicin combination. METHODS Liquid chromatography-mass spectrometry and RNA-seq analyses were conducted to identify the significant changes in the metabolome and transcriptome of P. aeruginosa PAO1 after exposure to polymyxin B (1 mg/L) and rifampicin (2 mg/L) alone, or in combination over 24 h. A genome-scale metabolic network was employed for integrative analysis. RESULTS In the first 4-h treatment, polymyxin B monotherapy induced significant lipid perturbations, predominantly to fatty acids and glycerophospholipids, indicating a substantial disorganization of the bacterial outer membrane. Expression of ParRS, a two-component regulatory system involved in polymyxin resistance, was increased by polymyxin B alone. Rifampicin alone caused marginal metabolic perturbations but significantly affected gene expression at 24 h. The combination decreased the gene expression of quorum sensing regulated virulence factors at 1 h (e.g. key genes involved in phenazine biosynthesis, secretion system and biofilm formation); and increased the expression of peptidoglycan biosynthesis genes at 4 h. Notably, the combination caused substantial accumulation of nucleotides and amino acids that last at least 4 h, indicating that bacterial cells were in a state of metabolic arrest. CONCLUSION This study underscores the substantial potential of integrative systems pharmacology to determine mechanisms of synergistic bacterial killing by antibiotic combinations, which will help optimize their use in patients.
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Affiliation(s)
- Mohd Hafidz Mahamad Maifiah
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
- International Institute for Halal Research and Training, International Islamic University Malaysia, 50728, Kuala Lumpur, Malaysia
| | - Yan Zhu
- Infection Program and Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, 3800, Australia
| | - Brian T Tsuji
- Department of Pharmacy Practice, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Darren J Creek
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Tony Velkov
- Department of Biochemistry and Pharmacology, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Jian Li
- Infection Program and Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, 3800, Australia.
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13
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Dawan J, Ahn J. Bacterial Stress Responses as Potential Targets in Overcoming Antibiotic Resistance. Microorganisms 2022; 10:microorganisms10071385. [PMID: 35889104 PMCID: PMC9322497 DOI: 10.3390/microorganisms10071385] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/03/2022] [Accepted: 07/08/2022] [Indexed: 12/23/2022] Open
Abstract
Bacteria can be adapted to adverse and detrimental conditions that induce general and specific responses to DNA damage as well as acid, heat, cold, starvation, oxidative, envelope, and osmotic stresses. The stress-triggered regulatory systems are involved in bacterial survival processes, such as adaptation, physiological changes, virulence potential, and antibiotic resistance. Antibiotic susceptibility to several antibiotics is reduced due to the activation of stress responses in cellular physiology by the stimulation of resistance mechanisms, the promotion of a resistant lifestyle (biofilm or persistence), and/or the induction of resistance mutations. Hence, the activation of bacterial stress responses poses a serious threat to the efficacy and clinical success of antibiotic therapy. Bacterial stress responses can be potential targets for therapeutic alternatives to antibiotics. An understanding of the regulation of stress response in association with antibiotic resistance provides useful information for the discovery of novel antimicrobial adjuvants and the development of effective therapeutic strategies to control antibiotic resistance in bacteria. Therefore, this review discusses bacterial stress responses linked to antibiotic resistance in Gram-negative bacteria and also provides information on novel therapies targeting bacterial stress responses that have been identified as potential candidates for the effective control of Gram-negative antibiotic-resistant bacteria.
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Affiliation(s)
- Jirapat Dawan
- Department of Biomedical Science, Kangwon National University, Chuncheon 24341, Gangwon, Korea;
| | - Juhee Ahn
- Department of Biomedical Science, Kangwon National University, Chuncheon 24341, Gangwon, Korea;
- Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon 24341, Gangwon, Korea
- Correspondence: ; Tel.: +82-33-250-6564
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14
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Sionov RV, Steinberg D. Targeting the Holy Triangle of Quorum Sensing, Biofilm Formation, and Antibiotic Resistance in Pathogenic Bacteria. Microorganisms 2022; 10:1239. [PMID: 35744757 PMCID: PMC9228545 DOI: 10.3390/microorganisms10061239] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 06/12/2022] [Accepted: 06/14/2022] [Indexed: 12/12/2022] Open
Abstract
Chronic and recurrent bacterial infections are frequently associated with the formation of biofilms on biotic or abiotic materials that are composed of mono- or multi-species cultures of bacteria/fungi embedded in an extracellular matrix produced by the microorganisms. Biofilm formation is, among others, regulated by quorum sensing (QS) which is an interbacterial communication system usually composed of two-component systems (TCSs) of secreted autoinducer compounds that activate signal transduction pathways through interaction with their respective receptors. Embedded in the biofilms, the bacteria are protected from environmental stress stimuli, and they often show reduced responses to antibiotics, making it difficult to eradicate the bacterial infection. Besides reduced penetration of antibiotics through the intricate structure of the biofilms, the sessile biofilm-embedded bacteria show reduced metabolic activity making them intrinsically less sensitive to antibiotics. Moreover, they frequently express elevated levels of efflux pumps that extrude antibiotics, thereby reducing their intracellular levels. Some efflux pumps are involved in the secretion of QS compounds and biofilm-related materials, besides being important for removing toxic substances from the bacteria. Some efflux pump inhibitors (EPIs) have been shown to both prevent biofilm formation and sensitize the bacteria to antibiotics, suggesting a relationship between these processes. Additionally, QS inhibitors or quenchers may affect antibiotic susceptibility. Thus, targeting elements that regulate QS and biofilm formation might be a promising approach to combat antibiotic-resistant biofilm-related bacterial infections.
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Affiliation(s)
- Ronit Vogt Sionov
- The Biofilm Research Laboratory, The Institute of Biomedical and Oral Research, The Faculty of Dental Medicine, Hadassah Medical School, The Hebrew University, Jerusalem 9112102, Israel;
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15
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Sauvage S, Gaviard C, Tahrioui A, Coquet L, Le H, Alexandre S, Ben Abdelkrim A, Bouffartigues E, Lesouhaitier O, Chevalier S, Jouenne T, Hardouin J. Impact of Carbon Source Supplementations on Pseudomonas aeruginosa Physiology. J Proteome Res 2022; 21:1392-1407. [PMID: 35482949 DOI: 10.1021/acs.jproteome.1c00936] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen highly resistant to a wide range of antimicrobial agents, making its infections very difficult to treat. Since microorganisms need to perpetually adapt to their surrounding environment, understanding the effect of carbon sources on P. aeruginosa physiology is therefore essential to avoid increasing drug-resistance and better fight this pathogen. By a global proteomic approach and phenotypic assays, we investigated the impact of various carbon source supplementations (glucose, glutamate, succinate, and citrate) on the physiology of the P. aeruginosa PA14 strain. A total of 581 proteins were identified as differentially expressed in the 4 conditions. Most of them were more abundant in citrate supplementation and were involved in virulence, motility, biofilm development, and antibiotic resistance. Phenotypic assays were performed to check these hypotheses. By coupling all this data, we highlight the importance of the environment in which the bacterium evolves on its metabolism, and thus the necessity to better understand the metabolic pathways implied in its adaptative response according to the nutrient availability.
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Affiliation(s)
- Salomé Sauvage
- Normandie Université, UNIROUEN, INSA, CNRS Polymers, Biopolymers, Surface Laboratory, 76821 Mont-Saint-Aignan cedex, France.,PISSARO Proteomic Facility, IRIB, 76820 Mont-Saint-Aignan, France
| | - Charlotte Gaviard
- Normandie Université, UNIROUEN, INSA, CNRS Polymers, Biopolymers, Surface Laboratory, 76821 Mont-Saint-Aignan cedex, France.,PISSARO Proteomic Facility, IRIB, 76820 Mont-Saint-Aignan, France
| | - Ali Tahrioui
- Laboratoire de microbiologie signaux et microenvironnement, LMSM EA4312, 55 rue Saint-Germain, 27000 Evreux, France
| | - Laurent Coquet
- Normandie Université, UNIROUEN, INSA, CNRS Polymers, Biopolymers, Surface Laboratory, 76821 Mont-Saint-Aignan cedex, France.,PISSARO Proteomic Facility, IRIB, 76820 Mont-Saint-Aignan, France
| | - Hung Le
- Normandie Université, UNIROUEN, INSA, CNRS Polymers, Biopolymers, Surface Laboratory, 76821 Mont-Saint-Aignan cedex, France
| | - Stéphane Alexandre
- Normandie Université, UNIROUEN, INSA, CNRS Polymers, Biopolymers, Surface Laboratory, 76821 Mont-Saint-Aignan cedex, France
| | - Ahmed Ben Abdelkrim
- Lactanet, Valacta, 555 Boul des Anciens-Combattants, Sainte-Anne-de-Bellevue, Québec H9X 3R4, Canada
| | - Emeline Bouffartigues
- Laboratoire de microbiologie signaux et microenvironnement, LMSM EA4312, 55 rue Saint-Germain, 27000 Evreux, France
| | - Olivier Lesouhaitier
- Laboratoire de microbiologie signaux et microenvironnement, LMSM EA4312, 55 rue Saint-Germain, 27000 Evreux, France
| | - Sylvie Chevalier
- Laboratoire de microbiologie signaux et microenvironnement, LMSM EA4312, 55 rue Saint-Germain, 27000 Evreux, France
| | - Thierry Jouenne
- Normandie Université, UNIROUEN, INSA, CNRS Polymers, Biopolymers, Surface Laboratory, 76821 Mont-Saint-Aignan cedex, France.,PISSARO Proteomic Facility, IRIB, 76820 Mont-Saint-Aignan, France
| | - Julie Hardouin
- Normandie Université, UNIROUEN, INSA, CNRS Polymers, Biopolymers, Surface Laboratory, 76821 Mont-Saint-Aignan cedex, France.,PISSARO Proteomic Facility, IRIB, 76820 Mont-Saint-Aignan, France
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16
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Laborda P, Hernando-Amado S, Martínez JL, Sanz-García F. Antibiotic Resistance in Pseudomonas. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:117-143. [DOI: 10.1007/978-3-031-08491-1_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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17
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Cell Envelope Stress Response in Pseudomonas aeruginosa. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:147-184. [DOI: 10.1007/978-3-031-08491-1_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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18
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Ducret V, Perron K, Valentini M. Role of Two-Component System Networks in Pseudomonas aeruginosa Pathogenesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:371-395. [PMID: 36258080 DOI: 10.1007/978-3-031-08491-1_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Two-component systems (TCS) are the largest family of signaling systems in the bacterial kingdom. They enable bacteria to cope with a wide range of environmental conditions via the sensing of stimuli and the transduction of the signal into an appropriate cellular adaptation response. Pseudomonas aeruginosa possesses one of the richest arrays of TCSs in bacteria and they have been the subject of intense investigation for more than 20 years. Most of the P. aeruginosa TCSs characterized to date affect its pathogenesis, via the regulation of virulence factors expression, modulation of the synthesis of antibiotic/antimicrobial resistance mechanisms, and/or via linking virulence to energy metabolism. Here, we give an overview of the current knowledge on P. aeruginosa TCSs, citing key examples for each of the above-mentioned regulatory actions. We then conclude by mentioning few small molecule inhibitors of P. aeruginosa TCSs that have shown an antimicrobial action in vitro.
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Affiliation(s)
- Verena Ducret
- Microbiology Unit, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland
| | - Karl Perron
- Microbiology Unit, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland
| | - Martina Valentini
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
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19
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Brinkman FSL, Winsor GL, Done RE, Filloux A, Francis VI, Goldberg JB, Greenberg EP, Han K, Hancock REW, Haney CH, Häußler S, Klockgether J, Lamont IL, Levesque RC, Lory S, Nikel PI, Porter SL, Scurlock MW, Schweizer HP, Tümmler B, Wang M, Welch M. The Pseudomonas aeruginosa whole genome sequence: A 20th anniversary celebration. Adv Microb Physiol 2021; 79:25-88. [PMID: 34836612 DOI: 10.1016/bs.ampbs.2021.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Toward the end of August 2000, the 6.3 Mbp whole genome sequence of Pseudomonas aeruginosa strain PAO1 was published. With 5570 open reading frames (ORFs), PAO1 had the largest microbial genome sequenced up to that point in time-including a large proportion of metabolic, transport and antimicrobial resistance genes supporting its ability to colonize diverse environments. A remarkable 9% of its ORFs were predicted to encode proteins with regulatory functions, providing new insight into bacterial network complexity as a function of network size. In this celebratory article, we fast forward 20 years, and examine how access to this resource has transformed our understanding of P. aeruginosa. What follows is more than a simple review or commentary; we have specifically asked some of the leaders in the field to provide personal reflections on how the PAO1 genome sequence, along with the Pseudomonas Community Annotation Project (PseudoCAP) and Pseudomonas Genome Database (pseudomonas.com), have contributed to the many exciting discoveries in this field. In addition to bringing us all up to date with the latest developments, we also ask our contributors to speculate on how the next 20 years of Pseudomonas research might pan out.
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Affiliation(s)
- Fiona S L Brinkman
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Geoffrey L Winsor
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Rachel E Done
- Department of Pediatrics, Division of Pulmonary, Allergy and Immunology, Cystic Fibrosis, and Sleep, Emory Children's Center for Cystic Fibrosis and Airway Disease Research, Emory University School of Medicine, Atlanta, GA, United States
| | - Alain Filloux
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Vanessa I Francis
- Geoffrey Pope Building, University of Exeter, Exeter, United Kingdom
| | - Joanna B Goldberg
- Department of Pediatrics, Division of Pulmonary, Allergy and Immunology, Cystic Fibrosis, and Sleep, Emory Children's Center for Cystic Fibrosis and Airway Disease Research, Emory University School of Medicine, Atlanta, GA, United States
| | - E Peter Greenberg
- Department of Microbiology, University of Washington, Seattle, WA, United States
| | - Kook Han
- Department of Microbiology, Harvard Medical School, Boston, MA, United States
| | | | - Cara H Haney
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, Canada
| | - Susanne Häußler
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Jens Klockgether
- Klinik für Pädiatrische Pneumologie, Allergologie und Neonatologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Iain L Lamont
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Roger C Levesque
- Institut de biologie intégrative et des systèmes (IBIS), Pavillon Charles-Eugène Marchand, Faculté of Médicine, Université Laval, Québec City, QC, Canada
| | - Stephen Lory
- Department of Microbiology, Harvard Medical School, Boston, MA, United States
| | - Pablo I Nikel
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Steven L Porter
- Geoffrey Pope Building, University of Exeter, Exeter, United Kingdom
| | | | - Herbert P Schweizer
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, United States
| | - Burkhard Tümmler
- Klinik für Pädiatrische Pneumologie, Allergologie und Neonatologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Meng Wang
- Department of Biochemistry (Hopkins Building), University of Cambridge, Cambridge, United Kingdom
| | - Martin Welch
- Department of Biochemistry (Hopkins Building), University of Cambridge, Cambridge, United Kingdom.
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20
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Georgieva M, Heinonen T, Vitale A, Hargraves S, Causevic S, Pillonel T, Eberl L, Widmann C, Jacquier N. Bacterial surface properties influence the activity of the TAT-RasGAP 317-326 antimicrobial peptide. iScience 2021; 24:102923. [PMID: 34430812 PMCID: PMC8365389 DOI: 10.1016/j.isci.2021.102923] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 07/05/2021] [Accepted: 07/27/2021] [Indexed: 12/13/2022] Open
Abstract
Antibiotic resistance is an increasing threat for public health, underscoring the need for new antibacterial agents. Antimicrobial peptides (AMPs) represent an alternative to classical antibiotics. TAT-RasGAP317-326 is a recently described AMP effective against a broad range of bacteria, but little is known about the conditions that may influence its activity. Using RNA-sequencing and screening of mutant libraries, we show that Escherichia coli and Pseudomonas aeruginosa respond to TAT-RasGAP317-326 by regulating metabolic and stress response pathways, possibly implicating two-component systems. Our results also indicate that bacterial surface properties, in particular integrity of the lipopolysaccharide layer, influence peptide binding and entry. Finally, we found differences between bacterial species with respect to their rate of resistance emergence against this peptide. Our findings provide the basis for future investigation on the mode of action of TAT-RasGAP317-326, which may help developing antimicrobial treatments based on this peptide.
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Affiliation(s)
- Maria Georgieva
- Department of Biomedical Sciences, University of Lausanne, Lausanne 1005, Switzerland
| | - Tytti Heinonen
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne 1011, Switzerland
| | - Alessandra Vitale
- Department of Plant and Microbial Biology, University of Zurich, Zurich 8008, Switzerland
| | - Simone Hargraves
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne 1011, Switzerland
| | - Senka Causevic
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne 1011, Switzerland
| | - Trestan Pillonel
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne 1011, Switzerland
| | - Leo Eberl
- Department of Plant and Microbial Biology, University of Zurich, Zurich 8008, Switzerland
| | - Christian Widmann
- Department of Biomedical Sciences, University of Lausanne, Lausanne 1005, Switzerland
- Corresponding author
| | - Nicolas Jacquier
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne 1011, Switzerland
- Corresponding author
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21
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Groisman EA, Duprey A, Choi J. How the PhoP/PhoQ System Controls Virulence and Mg 2+ Homeostasis: Lessons in Signal Transduction, Pathogenesis, Physiology, and Evolution. Microbiol Mol Biol Rev 2021; 85:e0017620. [PMID: 34191587 PMCID: PMC8483708 DOI: 10.1128/mmbr.00176-20] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The PhoP/PhoQ two-component system governs virulence, Mg2+ homeostasis, and resistance to a variety of antimicrobial agents, including acidic pH and cationic antimicrobial peptides, in several Gram-negative bacterial species. Best understood in Salmonella enterica serovar Typhimurium, the PhoP/PhoQ system consists o-regulated gene products alter PhoP-P amounts, even under constant inducing conditions. PhoP-P controls the abundance of hundreds of proteins both directly, by having transcriptional effects on the corresponding genes, and indirectly, by modifying the abundance, activity, or stability of other transcription factors, regulatory RNAs, protease regulators, and metabolites. The investigation of PhoP/PhoQ has uncovered novel forms of signal transduction and the physiological consequences of regulon evolution.
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Affiliation(s)
- Eduardo A. Groisman
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
- Yale Microbial Sciences Institute, West Haven, Connecticut, USA
| | - Alexandre Duprey
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Jeongjoon Choi
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
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22
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Tabor LM, Grosser MR, Metruccio MMME, Kumar NG, Wu YT, Nieto V, Evans DJ, Fleiszig SMJ. Human tear fluid modulates the Pseudomonas aeruginosa transcriptome to alter antibiotic susceptibility. Ocul Surf 2021; 22:94-102. [PMID: 34332149 PMCID: PMC10139757 DOI: 10.1016/j.jtos.2021.07.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 06/08/2021] [Accepted: 07/26/2021] [Indexed: 11/24/2022]
Abstract
PURPOSE Previously, we showed that tear fluid protects corneal epithelial cells against Pseudomonas aeruginosa without suppressing bacterial viability. Here, we studied how tear fluid affects bacterial gene expression. METHODS RNA-sequencing was used to study the P. aeruginosa transcriptome after tear fluid exposure (5 h, 37 oC). Outcomes were further investigated by biochemical and physiological perturbations to tear fluid and tear-like fluid (TLF) and assessment of bacterial viability following tear/TLF pretreatment and antibiotic exposure. RESULTS Tear fluid deregulated ~180 P. aeruginosa genes ≥8 fold versus PBS including downregulating lasI, rhlI, qscR (quorum sensing/virulence), oprH, phoP, phoQ (antimicrobial resistance) and arnBCADTEF (polymyxin B resistance). Upregulated genes included algF (biofilm formation) and hemO (iron acquisition). qPCR confirmed tear down-regulation of oprH, phoP and phoQ. Tear fluid pre-treatment increased P. aeruginosa resistance to meropenem ~5-fold (4 μg/ml), but enhanced polymyxin B susceptibility ~180-fold (1 μg/ml), the latter activity reduced by dilution in PBS. Media containing a subset of tear components (TLF) also sensitized bacteria to polymyxin B, but only ~22.5-fold, correlating with TLF/tear fluid Ca2+ and Mg2+ concentrations. Accordingly, phoQ mutants were not sensitized by TLF or tear fluid. Superior activity of tear fluid versus TLF against wild-type P. aeruginosa was heat resistant but proteinase K sensitive. CONCLUSION P. aeruginosa responds to human tear fluid by upregulating genes associated with bacterial survival and adaptation. Meanwhile, tear fluid down-regulates multiple virulence-associated genes. Tears also utilize divalent cations and heat resistant/proteinase K sensitive component(s) to enhance P. aeruginosa sensitivity to polymyxin B.
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Affiliation(s)
- Lauren M Tabor
- School of Optometry, University of California, Berkeley, CA, USA
| | | | | | - Naren G Kumar
- School of Optometry, University of California, Berkeley, CA, USA
| | - Yvonne T Wu
- School of Optometry, University of California, Berkeley, CA, USA
| | - Vincent Nieto
- School of Optometry, University of California, Berkeley, CA, USA
| | - David J Evans
- School of Optometry, University of California, Berkeley, CA, USA; College of Pharmacy, Touro University California, Vallejo, CA, USA
| | - Suzanne M J Fleiszig
- School of Optometry, University of California, Berkeley, CA, USA; Graduate Groups in Vision Science, Microbiology, and Infectious Diseases & Immunity, University of California, Berkeley, CA, USA.
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Maynard M, Drusano GL, Vicchiarelli M, Liu W, Myrick J, Nole J, Duncanson B, Brown D, Louie A. Polymyxin B Pharmacodynamics in the Hollow-Fiber Infection Model: What You See May Not Be What You Get. Antimicrob Agents Chemother 2021; 65:e0185320. [PMID: 34097487 PMCID: PMC8284464 DOI: 10.1128/aac.01853-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 04/25/2021] [Indexed: 11/20/2022] Open
Abstract
Dose range studies for polymyxin B (PMB) regimens of 0.75 to 12 mg/kg given every 12 h (q12h) were evaluated for bacterial killing and resistance prevention against an AmpC-overexpressing Pseudomonas aeruginosa and a blaKPC-3-harboring Klebsiella pneumoniae in 10-day in vitro hollow-fiber models. An exposure-response was observed. But all regimens failed due to regrowth. Lower-dose regimens amplified isolates that expressed transient, lower-level adaptive resistance to PMB (MICs ≤ 4 mg/liter). Higher PMB dosages amplified isolates that expressed this resistance mechanism, a higher-MIC "moderately stable" adaptive resistance, and a higher-MIC stable resistance to PMB. Failure of the highest dose regimens was solely due to subpopulations that expressed the two higher-level resistances. Total and bioactive PMB concentrations in broth declined below targeted PK profiles within hours of treatment initiation and prior to bacterial regrowth. With treatment failure, the total PMB measured in bacteria was substantially higher than in broth. But the bioactive PMB in broth and bacteria were low to nondetectable. Together, these findings suggest a sequence of events for treatment failure of the clinical regimen. First, PMB concentrations in broth are diluted as PMB binds to bacteria, resulting in total and bioactive PMB in broth that is lower than targeted. Bacterial regrowth and treatment failure follow, with emergence of subpopulations that express transient lower-level adaptive resistance to PMB and possibly higher-level adaptive and stable resistances. Higher-dose PMB regimens can prevent the emergence of transient lower-level adaptive resistance, but they do not prevent treatment failure due to isolates that express higher-level resistance mechanisms.
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Affiliation(s)
- Michael Maynard
- Institute for Therapeutic Innovation, University of Florida, Orlando, Florida, USA
| | - G. L. Drusano
- Institute for Therapeutic Innovation, University of Florida, Orlando, Florida, USA
| | - Michael Vicchiarelli
- Institute for Therapeutic Innovation, University of Florida, Orlando, Florida, USA
| | - Weiguo Liu
- Institute for Therapeutic Innovation, University of Florida, Orlando, Florida, USA
| | - Jenny Myrick
- Institute for Therapeutic Innovation, University of Florida, Orlando, Florida, USA
| | - Jocelyn Nole
- Institute for Therapeutic Innovation, University of Florida, Orlando, Florida, USA
| | - Brandon Duncanson
- Institute for Therapeutic Innovation, University of Florida, Orlando, Florida, USA
| | - David Brown
- Institute for Therapeutic Innovation, University of Florida, Orlando, Florida, USA
| | - Arnold Louie
- Institute for Therapeutic Innovation, University of Florida, Orlando, Florida, USA
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Huang HH, Wu BK, Li LH, Lin YT, Yang TC. Role of the PhoPQ two-component regulatory system in the β-lactam resistance of Stenotrophomonas maltophilia. J Antimicrob Chemother 2021; 76:1480-1486. [PMID: 33739413 DOI: 10.1093/jac/dkab059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 02/09/2021] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Stenotrophomonas maltophilia, an opportunistic pathogen, is intrinsically resistant to most β-lactams except ceftazidime and ticarcillin/clavulanate, due to the inducibly expressed L1 and L2 β-lactamases. A two-component regulatory system (TCS) allows organisms to sense and respond to changes in different environmental conditions. The PhoPQ TCS of S. maltophilia plays regulatory roles in antibiotic susceptibility, physiology, stress adaption and virulence. Inactivation of S. maltophilia phoPQ increases β-lactam susceptibility. OBJECTIVES To elucidate the PhoPQ-regulating mechanism for β-lactam resistance. METHODS The candidate genes responsible for the ΔphoPQ-mediated β-lactam resistance compromise were identified by transcriptome analysis and verified by quantitative RT-PCR and complementation assay. Etest was used to assess β-lactam susceptibility. The phosphorylation level of the PhoP protein was determined by Phos-tag SDS-PAGE and western blotting. A β-lactam influx assay was used to investigate the influx efficiency of a β-lactam. RESULTS PhoPQ deletion down-regulated the expression of mltD1 and slt, attenuated the induced β-lactamase activity and then compromised the β-lactam resistance. Complementation of mutant phoPQ with mltD1 or slt genes partially reverted the induced β-lactamase activity and β-lactam resistance. The PhoPQ TCS was activated in logarithmically grown KJ cells and was further activated by low magnesium, but not by a β-lactam. However, low-magnesium-mediated PhoPQ activation hardly made an impact on β-lactam resistance enhancement. Furthermore, PhoPQ inactivation altered the outer membrane permeability and increased the influx of a β-lactam. CONCLUSIONS The PhoPQ TCS is activated to some extent in physiologically grown S. maltophilia. Inactivation of phoPQ attenuates the expression of mltD1 and slt, and increases β-lactam influx, both synergically contributing to β-lactam resistance compromise.
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Affiliation(s)
- Hsin-Hui Huang
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Bo-Kuan Wu
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Li-Hua Li
- Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,Ph.D. Program in Medical Biotechnology, Taipei Medical University, Taipei, Taiwan
| | - Yi-Tsung Lin
- Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Tsuey-Ching Yang
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan
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The Xanthomonas RaxH-RaxR Two-Component Regulatory System Is Orthologous to the Zinc-Responsive Pseudomonas ColS-ColR System. Microorganisms 2021; 9:microorganisms9071458. [PMID: 34361895 PMCID: PMC8306577 DOI: 10.3390/microorganisms9071458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 06/30/2021] [Accepted: 07/02/2021] [Indexed: 01/08/2023] Open
Abstract
Genome sequence comparisons to infer likely gene functions require accurate ortholog assignments. In Pseudomonas spp., the sensor-regulator ColS-ColR two-component regulatory system responds to zinc and other metals to control certain membrane-related functions, including lipid A remodeling. In Xanthomonas spp., three different two-component regulatory systems, RaxH-RaxR, VgrS-VgrR, and DetS-DetR, have been denoted as ColS-ColR in several different genome annotations and publications. To clarify these assignments, we compared the sensor periplasmic domain sequences and found that those from Pseudomonas ColS and Xanthomonas RaxH share a similar size as well as the location of a Glu-X-X-Glu metal ion-binding motif. Furthermore, we determined that three genes adjacent to raxRH are predicted to encode enzymes that remodel the lipid A component of lipopolysaccharide. The modifications catalyzed by lipid A phosphoethanolamine transferase (EptA) and lipid A 1-phosphatase (LpxE) previously were detected in lipid A from multiple Xanthomonas spp. The third gene encodes a predicted lipid A glycosyl transferase (ArnT). Together, these results indicate that the Xanthomonas RaxH-RaxR system is orthologous to the Pseudomonas ColS-ColR system that regulates lipid A remodeling. To avoid future confusion, we recommend that the terms ColS and ColR no longer be applied to Xanthomonas spp., and that the Vgr, Rax, and Det designations be used instead.
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Various Novel Colistin Resistance Mechanisms Interact To Facilitate Adaptation of Aeromonas hydrophila to Complex Colistin Environments. Antimicrob Agents Chemother 2021; 65:e0007121. [PMID: 33903105 PMCID: PMC8373241 DOI: 10.1128/aac.00071-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Aeromonas hydrophila, a heterotrophic and Gram-negative bacterium, has attracted considerable attention owing to the increasing prevalence of reported infections. Colistin is a last-resort antibiotic that can treat life-threatening infections caused by multidrug-resistant Gram-negative bacteria. However, the mechanisms underlying colistin resistance in A. hydrophila remain unclear. The present study reveals four novel colistin resistance mechanisms in A. hydrophila: (i) EnvZ/OmpR upregulates the expression of the arnBCADTEF operon to mediate lipopolysaccharide (LPS) modification by 4-amino-4-deoxy-l-arabinose, (ii) EnvZ/OmpR regulates the expression of the autotransporter gene3832 to decrease outer membrane permeability in response to colistin, (iii) deletion of envZ/ompR activates PhoP/PhoQ, which functions as a substitute two-component system to mediate the addition of phosphoethanolamine to lipid A via pmrC, and (iv) the mlaFD173A mutant confers high-level colistin resistance via upregulation of the Mla pathway. The EnvZ/OmpR two-component system-mediated resistance mechanism is the leading form of colistin resistance in A. hydrophila, which enables it to rapidly generate low- to medium-level colistin resistance. As colistin concentrations in the environment continue to rise, antibiotic resistance mediated by EnvZ/OmpR becomes insufficient to ensure bacterial survival. Consequently, A. hydrophila has developed an mlaF mutation that results in high-level colistin resistance. Our findings indicate that A. hydrophila can thrive in a complex environment through various colistin resistance mechanisms.
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Abstract
Antibiotic resistance is a major global health challenge and, worryingly, several key Gram negative pathogens can become resistant to most currently available antibiotics. Polymyxins have been revived as a last-line therapeutic option for the treatment of infections caused by multidrug-resistant Gram negative bacteria, in particular Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacterales. Polymyxins were first discovered in the late 1940s but were abandoned soon after their approval in the late 1950s as a result of toxicities (e.g., nephrotoxicity) and the availability of "safer" antibiotics approved at that time. Therefore, knowledge on polymyxins had been scarce until recently, when enormous efforts have been made by several research teams around the world to elucidate the chemical, microbiological, pharmacokinetic/pharmacodynamic, and toxicological properties of polymyxins. One of the major achievements is the development of the first scientifically based dosage regimens for colistin that are crucial to ensure its safe and effective use in patients. Although the guideline has not been developed for polymyxin B, a large clinical trial is currently being conducted to optimize its clinical use. Importantly, several novel, safer polymyxin-like lipopeptides are developed to overcome the nephrotoxicity, poor efficacy against pulmonary infections, and narrow therapeutic windows of the currently used polymyxin B and colistin. This review discusses the latest achievements on polymyxins and highlights the major challenges ahead in optimizing their clinical use and discovering new-generation polymyxins. To save lives from the deadly infections caused by Gram negative "superbugs," every effort must be made to improve the clinical utility of the last-line polymyxins. SIGNIFICANCE STATEMENT: Antimicrobial resistance poses a significant threat to global health. The increasing prevalence of multidrug-resistant (MDR) bacterial infections has been highlighted by leading global health organizations and authorities. Polymyxins are a last-line defense against difficult-to-treat MDR Gram negative pathogens. Unfortunately, the pharmacological information on polymyxins was very limited until recently. This review provides a comprehensive overview on the major achievements and challenges in polymyxin pharmacology and clinical use and how the recent findings have been employed to improve clinical practice worldwide.
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Affiliation(s)
- Sue C Nang
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
| | - Mohammad A K Azad
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
| | - Tony Velkov
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
| | - Qi Tony Zhou
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
| | - Jian Li
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
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Wang T, Sun W, Fan L, Hua C, Wu N, Fan S, Zhang J, Deng X, Yan J. An atlas of the binding specificities of transcription factors in Pseudomonas aeruginosa directs prediction of novel regulators in virulence. eLife 2021; 10:61885. [PMID: 33779544 PMCID: PMC8041468 DOI: 10.7554/elife.61885] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 03/26/2021] [Indexed: 12/14/2022] Open
Abstract
A high-throughput systematic evolution of ligands by exponential enrichment assay was applied to 371 putative TFs in Pseudomonas aeruginosa, which resulted in the robust enrichment of 199 unique sequence motifs describing the binding specificities of 182 TFs. By scanning the genome, we predicted in total 33,709 significant interactions between TFs and their target loci, which were more than 11-fold enriched in the intergenic regions but depleted in the gene body regions. To further explore and delineate the physiological and pathogenic roles of TFs in P. aeruginosa, we constructed regulatory networks for nine major virulence-associated pathways and found that 51 TFs were potentially significantly associated with these virulence pathways, 32 of which had not been characterized before, and some were even involved in multiple pathways. These results will significantly facilitate future studies on transcriptional regulation in P. aeruginosa and other relevant pathogens, and accelerate to discover effective treatment and prevention strategies for the associated infectious diseases.
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Affiliation(s)
- Tingting Wang
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Wenju Sun
- School of Medicine, Northwest University, Xi'an, China
| | - Ligang Fan
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China.,School of Medicine, Northwest University, Xi'an, China
| | - Canfeng Hua
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Nan Wu
- School of Medicine, Northwest University, Xi'an, China
| | - Shaorong Fan
- School of Medicine, Northwest University, Xi'an, China
| | - Jilin Zhang
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, Sweden
| | - Xin Deng
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Jian Yan
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China.,School of Medicine, Northwest University, Xi'an, China
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Zhang Z, Ortega D, Rush A, Blankenship LR, Cheng ZJ, Moore RE, Tran MLN, Sandoval LG, Aboulhosn K, Watanabe S, Cortez KS, Perlman DH, Semmelhack MF, Miller Conrad LC. Antibiotic Adjuvant Activity Revealed in a Photoaffinity Approach to Determine the Molecular Target of Antipyocyanin Compounds. ACS Infect Dis 2021; 7:535-543. [PMID: 33587590 DOI: 10.1021/acsinfecdis.0c00160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Infections with Pseudomonas aeruginosa are a looming threat to public health. New treatment strategies are needed to combat this pathogen, for example, by blocking the production of virulence factors like pyocyanin. A photoaffinity analogue of an antipyocyanin compound was developed to interrogate the inhibitor's molecular mechanism of action. While we sought to develop antivirulence inhibitors, the proteomics results suggested that the compounds had antibiotic adjuvant activity. Unexpectedly, we found that these compounds amplify the bactericidal activity of colistin, a well-characterized antibiotic, suggesting they may represent a first-in-class antibiotic adjuvant therapy. Analogues have the potential not only to widen the therapeutic index of cationic antimicrobial peptides like colistin, but also to be effective against colistin-resistant strains, strengthening our arsenal to combat P. aeruginosa infections.
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Affiliation(s)
- Zinan Zhang
- Department of Chemistry, Princeton University, Washington Road, Princeton, New Jersey 08544, United States
| | - Dominic Ortega
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
| | - Anthony Rush
- Department of Bioengineering, Stanford University, 443 Via Ortega, Stanford, California 94305, United States
| | - Lauren R. Blankenship
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
| | - Zi Jun Cheng
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
| | - Rebecca E. Moore
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
| | - Minh L. N. Tran
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
| | - Lucero G. Sandoval
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
| | - Kareem Aboulhosn
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
| | - Seiichiro Watanabe
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
| | - Kendra S. Cortez
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
| | - David H. Perlman
- Princeton Proteomics and Mass Spectrometry Center, Princeton University, Washington Road, Princeton, New Jersey 08544, United States
| | - Martin F. Semmelhack
- Department of Chemistry, Princeton University, Washington Road, Princeton, New Jersey 08544, United States
| | - Laura C. Miller Conrad
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
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30
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Yang B, Liu C, Pan X, Fu W, Fan Z, Jin Y, Bai F, Cheng Z, Wu W. Identification of Novel PhoP-PhoQ Regulated Genes That Contribute to Polymyxin B Tolerance in Pseudomonas aeruginosa. Microorganisms 2021; 9:microorganisms9020344. [PMID: 33572426 PMCID: PMC7916210 DOI: 10.3390/microorganisms9020344] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/06/2021] [Accepted: 02/08/2021] [Indexed: 12/14/2022] Open
Abstract
Polymyxin B and E (colistin) are the last resorts to treat multidrug-resistant Gram-negative pathogens. Pseudomonas aeruginosa is intrinsically resistant to a variety of antibiotics. The PhoP-PhoQ two-component regulatory system contributes to the resistance to polymyxins by regulating an arnBCADTEF-pmrE operon that encodes lipopolysaccharide modification enzymes. To identify additional PhoP-regulated genes that contribute to the tolerance to polymyxin B, we performed a chromatin immunoprecipitation sequencing (ChIP-Seq) assay and found novel PhoP binding sites on the chromosome. We further verified that PhoP directly controls the expression of PA14_46900, PA14_50740 and PA14_52340, and the operons of PA14_11970-PA14_11960 and PA14_52350-PA14_52370. Our results demonstrated that mutation of PA14_46900 increased the bacterial binding and susceptibility to polymyxin B. Meanwhile, mutation of PA14_11960 (papP), PA14_11970 (mpl), PA14_50740 (slyB), PA14_52350 (ppgS), and PA14_52370 (ppgH) reduced the bacterial survival rates and increased ethidium bromide influx under polymyxin B or Sodium dodecyl sulfate (SDS) treatment, indicating roles of these genes in maintaining membrane integrity in response to the stresses. By 1-N-phenylnaphthylamine (NPN) and propidium iodide (PI) staining assay, we found that papP and slyB are involved in maintaining outer membrane integrity, and mpl and ppgS-ppgH are involved in maintaining inner membrane integrity. Overall, our results reveal novel PhoP-PhoQ regulated genes that contribute to polymyxin B tolerance.
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Nageeb W, Amin DH, Mohammedsaleh ZM, Makharita RR. Novel Molecular Markers Linked to Pseudomonas aeruginosa Epidemic High-Risk Clones. Antibiotics (Basel) 2021; 10:antibiotics10010035. [PMID: 33401446 PMCID: PMC7824207 DOI: 10.3390/antibiotics10010035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/21/2020] [Accepted: 12/28/2020] [Indexed: 11/16/2022] Open
Abstract
The population structure of Pseudomonas aeruginosa is panmictic-epidemic in nature, with the prevalence of some high-risk clones. These clones are often linked to virulence, antibiotic resistance, and more morbidity. The clonal success of these lineages has been linked to acquisition and spread of mobile genetic elements. The main aim of the study was to explore other molecular markers that explain their global success. A comprehensive set of 528 completely sequenced P. aeruginosa genomes was analyzed. The population structure was examined using Multilocus Sequence Typing (MLST). Strain relationships analysis and diversity analysis were performed using the geoBURST Full Minimum Spanning Tree (MST) algorithm and hierarchical clustering. A phylogenetic tree was constructed using the Unweighted Pair Group Method with Arithmetic mean (UPGMA) algorithm. A panel of previously investigated resistance markers were examined for their link to high-risk clones. A novel panel of molecular markers has been identified in relation to risky clones including armR, ampR, nalC, nalD, mexZ, mexS, gyrAT83I, gyrAD87N, nalCE153Q, nalCS46A, parCS87W, parCS87L, ampRG283E, ampRM288R, pmrALeu71Arg, pmrBGly423Cys, nuoGA890T, pstBE89Q, phoQY85F, arnAA170T, arnDG206C, and gidBE186A. In addition to mobile genetic elements, chromosomal variants in membrane proteins and efflux pump regulators can play an important role in the success of high-risk clones. Finding risk-associated markers during molecular surveillance necessitates applying more infection-control precautions.
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Affiliation(s)
- Wedad Nageeb
- Medical Microbiology and Immunology Department, Faculty of Medicine, Suez Canal University, Ismailia 41111, Egypt
- Correspondence:
| | - Dina H. Amin
- Microbiology Department, Faculty of Science, Ain Shams University, Cairo 11566, Egypt;
| | - Zuhair M. Mohammedsaleh
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, University of Tabuk, Tabuk 71491, Saudi Arabia;
| | - Rabab R. Makharita
- Botany and Microbiology Department, Faculty of Science, Suez Canal University, Ismailia 41522, Egypt;
- Biology Department, Faculty of Science and Arts, Khulais, University of Jeddah, Jeddah 21959, Saudi Arabia
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Identification of novel targets of azithromycin activity against Pseudomonas aeruginosa grown in physiologically relevant media. Proc Natl Acad Sci U S A 2020; 117:33519-33529. [PMID: 33318204 DOI: 10.1073/pnas.2007626117] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pseudomonas aeruginosa causes severe multidrug-resistant infections that often lead to bacteremia and sepsis. Physiologically relevant conditions can increase the susceptibility of pathogens to antibiotics, such as azithromycin (AZM). When compared to minimal-inhibitory concentrations (MICs) in laboratory media, AZM had a 16-fold lower MIC in tissue culture medium with 5% Mueller Hinton broth (MHB) and a 64-fold lower MIC in this tissue culture medium with 20% human serum. AZM also demonstrated increased synergy in combination with synthetic host-defense peptides DJK-5 and IDR-1018 under host-like conditions and in a murine abscess model. To mechanistically study the altered effects of AZM under physiologically relevant conditions, global transcriptional analysis was performed on P. aeruginosa with and without effective concentrations of AZM. This revealed that the arn operon, mediating arabinosaminylation of lipopolysaccharides and related regulatory systems, was down-regulated in host-like media when compared to MHB. Inactivation of genes within the arn operon led to increased susceptibility of P. aeruginosa to AZM and great increases in synergy between AZM and other antimicrobial agents, indicating that dysregulation of the arn operon might explain increased AZM uptake and synergy in host-like media. Furthermore, genes involved in central and energy metabolism and ribosome biogenesis were dysregulated more in physiologically relevant conditions treated with AZM, likely due to general changes in cell physiology as a result of the increased effectiveness of AZM in these conditions. These data suggest that, in addition to the arn operon, there are multiple factors in host-like environments that are responsible for observed changes in susceptibility.
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Cerqueira F, Christou A, Fatta-Kassinos D, Vila-Costa M, Bayona JM, Piña B. Effects of prescription antibiotics on soil- and root-associated microbiomes and resistomes in an agricultural context. JOURNAL OF HAZARDOUS MATERIALS 2020; 400:123208. [PMID: 32593021 DOI: 10.1016/j.jhazmat.2020.123208] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 05/22/2020] [Accepted: 06/11/2020] [Indexed: 05/23/2023]
Abstract
The use of treated wastewater for crop irrigation is rapidly increasing to respond to the ever-growing demands for water and food resources. However, this practice may contribute to the spread of antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARGs) in agricultural settings. To evaluate this potential risk, we analyzed microbiomes and resistomes of soil and Lactuca sativa L. (lettuce) root samples from pots irrigated with tap water spiked with 0, 20, or 100 μg L-1 of a mixture of three antibiotics (Trimethoprim, Ofloxacin, Sulfamethoxazole). The presence of antibiotics induced changes in bacterial populations, particularly in soil, as revealed by 16S rDNA sequence analysis. Parallel shotgun sequencing identified a total of 56 different ARGs conferring resistance against 14 antibiotic families. Antibiotic -treated samples showed increased loads of ARGs implicated in mutidrug resistance or in both direct and indirect acquired resistance. These changes correlated with the prevalence of Xantomonadales species in the root microbiomes. We interpret these data as indicating different strategies of soil and root microbiomes to cope with the presence of antibiotics, and as a warning that their presence may increase the loads of ARBs and ARGs in edible plant parts, therefore constituting a potential risk for human consumers.
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Affiliation(s)
- Francisco Cerqueira
- Institute of Environmental Assessment and Water Research (IDAEA), Spanish National Research Council, Barcelona, Spain
| | - Anastasis Christou
- Agricultural Research Institute, Ministry of Agriculture, Rural Development and Environment, P.O. Box 22016, 1516, Nicosia, Cyprus
| | - Despo Fatta-Kassinos
- Civil and Environmental Engineering Department and Nireas, International Water Research Center, University of Cyprus, P.O. Box 20538, 1678, Nicosia, Cyprus
| | - Maria Vila-Costa
- Institute of Environmental Assessment and Water Research (IDAEA), Spanish National Research Council, Barcelona, Spain
| | - Josep Maria Bayona
- Institute of Environmental Assessment and Water Research (IDAEA), Spanish National Research Council, Barcelona, Spain
| | - Benjamin Piña
- Institute of Environmental Assessment and Water Research (IDAEA), Spanish National Research Council, Barcelona, Spain.
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Lu HF, Wu BK, Huang YW, Lee MZ, Li MF, Ho HJ, Yang HC, Yang TC. PhoPQ two-component regulatory system plays a global regulatory role in antibiotic susceptibility, physiology, stress adaptation, and virulence in Stenotrophomonas maltophilia. BMC Microbiol 2020; 20:312. [PMID: 33054754 PMCID: PMC7559202 DOI: 10.1186/s12866-020-01989-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 09/30/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Stenotrophomonas maltophilia, an opportunistic pathogen, is ubiquitously present in various environments, signifying its high capability of environmental adaptation. Two-component regulatory system (TCS) is a powerful implement to help organisms to survive in different environments. In clinic, treatment of S. maltophilia infection is difficult because it is naturally resistant to many antibiotics, highlighting the necessity to develop novel drugs or adjuvants. Given their critical and extensively regulatory role, TCS system has been proposed as a convincing target for novel drugs or adjuvants. PhoPQ TCS, a highly conserved TCS in several pathogens, plays crucial roles in low-magnesium adaption, polymyxin resistance, and virulence. In this study, we aimed to characterize the role of PhoPQ TCS of S. maltophilia in antibiotic susceptibility, physiology, stress adaptation, and virulence. RESULTS To characterize PhoPQ system, phoP single mutant as well as phoP and phoQ double mutant were constructed. Distinct from most phoPQ systems of other microorganisms, two features were observed during the construction of phoP and phoQ single deletion mutant. Firstly, the phoQ mutant was not successfully obtained. Secondly, the compromised phenotypes of phoP mutant were not reverted by complementing an intact phoP gene, but were partially restored by complementing a phoPQ operon. Thus, wild-type KJ, phoP mutant (KJΔPhoP), phoPQ mutant (KJΔPhoPQ), and complemented strain (KJΔPhoPQ (pPhoPQ)) were used for functional assays, including antibiotic susceptibility, physiology (swimming motility and secreted protease activity), stress adaptation (oxidative, envelope, and iron-depletion stresses), and virulence to Caenorhabditis elegans. KJΔPhoPQ totally lost swimming motility, had enhanced secreted protease activity, increased susceptibility to antibiotics (β-lactam, quinolone, aminoglycoside, macrolide, chloramphenicol, and sulfamethoxazole/ trimethoprim), menadione, H2O2, SDS, and 2,2'-dipyridyl, as well as attenuated virulence to C. elegans. Trans-complementation of KJΔPhoPQ with phoPQ reverted these altered phenotypes to the wild-type levels. CONCLUSIONS Given the critical and global roles of PhoPQ TCS in antibiotic susceptibility, physiology, stress adaptation, and virulence, PhoPQ is a potential target for the design of drugs or adjuvants.
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Affiliation(s)
- Hsu-Feng Lu
- Department of Clinical Pathology, Cheng Hsin General Hospital, Taipei, Taiwan
- Department of Restaurant, Hotel and Institutional Management, Fu-Jen Catholic University, New Taipei City, Taiwan
| | - Bo-Kuan Wu
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Yi-Wei Huang
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Ming-Zhe Lee
- Department of Clinical Pathology, Cheng Hsin General Hospital, Taipei, Taiwan
| | - Ming-Fang Li
- Department of Medical Laboratory Science and Biotechnology, Yuanpei University of Medical Technology, Hsinchu, Taiwan
| | - Hsu-Jung Ho
- Department of Medical Laboratory Science and Biotechnology, Yuanpei University of Medical Technology, Hsinchu, Taiwan
| | - Hung-Chi Yang
- Department of Medical Laboratory Science and Biotechnology, Yuanpei University of Medical Technology, Hsinchu, Taiwan.
| | - Tsuey-Ching Yang
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan.
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Sivakumar R, Gunasekaran P, Rajendhran J. Functional characterization of asnC family transcriptional regulator in Pseudomonas aeruginosa PGPR2 during root colonization. Mol Biol Rep 2020; 47:7941-7957. [PMID: 33011891 DOI: 10.1007/s11033-020-05872-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 09/28/2020] [Indexed: 12/18/2022]
Abstract
Transcriptional regulators in bacteria are the crucial players in mediating communication between environmental cues and DNA transcription through a complex network process. Pseudomonas aeruginosa PGPR2 is an efficient root colonizer and a biocontrol strain. Previously, we identified that the transcriptional regulator, asnC, negatively regulates the corn root colonization of P. aeruginosa PGPR2. In a transposon insertion sequencing (INSeq) screen, the asnC insertion mutant was positively selected during root colonization, meaning the disruption of asnC improves the fitness of the P. aeruginosa PGPR2 strain for the root colonization. In this study, we constructed isogenic mutant of asnC family transcriptional regulator encoded by PGPR2_17510 by allele exchange mutagenesis. The ΔasnC mutant was able to efficiently colonize corn roots with a twofold increase in population when compared to the wild-type strain. Similarly, the mutant strain outcompeted the wild-type strain in a competition assay, where the mutant strain represented 90% of the total population recovered from the root. We compared the whole transcriptome of the wild-type and the ΔasnC mutant of P. aeruginosa PGPR2 when exposed to the corn root exudates. The RNA-Seq revealed that a total of 360 genes were differentially expressed in the ΔasnC strain of P. aeruginosa PGPR2. Inactivation of asnC transcriptional regulator resulted in the up-regulation of several genetic factors implicated in metabolism, uptake of nutrients, motility, stress response, and signal transduction, which could play crucial roles in root colonization. This notion was further validated by phenotypic characterization and quantification of transcription pattern of selected genes associated with metabolism, motility, and carbon catabolite repression between wild type and mutant strain, which was in agreement with transcriptome data. Similarly, ΔasnC strain formed increased biofilm on abiotic surface validating our RNA-seq analysis, where transcript levels of several genes associated with biofilm formation were up-regulated in the mutant strain. We report that the inactivation of an asnC family transcriptional regulator encoded by PGPR2_17510 enhances the root colonization and biofilm-forming ability of P. aeruginosa PGPR2. Together, our results provide evidence for the molecular adaptations that enable ΔasnC mutant strain to colonize on the corn roots and to form a biofilm.
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Affiliation(s)
- Ramamoorthy Sivakumar
- Department of Genetics, School of Biological Sciences, Madurai Kamaraj University, Madurai, 625 021, India
| | | | - Jeyaprakash Rajendhran
- Department of Genetics, School of Biological Sciences, Madurai Kamaraj University, Madurai, 625 021, India.
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Shao X, Xie Y, Zhang Y, Liu J, Ding Y, Wu M, Wang X, Deng X. Novel therapeutic strategies for treating Pseudomonas aeruginosa infection. Expert Opin Drug Discov 2020; 15:1403-1423. [PMID: 32880507 DOI: 10.1080/17460441.2020.1803274] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Persistent infections caused by the superbug Pseudomonas aeruginosa and its resistance to multiple antimicrobial agents are huge threats to patients with cystic fibrosis as well as those with compromised immune systems. Multidrug-resistant P. aeruginosa has posed a major challenge to conventional antibiotics and therapeutic approaches, which show limited efficacy and cause serious side effects. The public demand for new antibiotics is enormous; yet, drug development pipelines have started to run dry with limited targets available for inventing new antibacterial drugs. Consequently, it is important to uncover potential therapeutic targets. AREAS COVERED The authors review the current state of drug development strategies that are promising in terms of the development of novel and potent drugs to treat P. aeruginosa infection. EXPERT OPINION The prevention of P. aeruginosa infection is increasingly challenging. Furthermore, targeting key virulence regulators has great potential for developing novel anti-P. aeruginosa drugs. Additional promising strategies include bacteriophage therapy, immunotherapies, and antimicrobial peptides. Additionally, the authors believe that in the coming years, the overall network of molecular regulatory mechanism of P. aeruginosa virulence will be fully elucidated, which will provide more novel and promising drug targets for treating P. aeruginosa infections.
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Affiliation(s)
- Xiaolong Shao
- Department of Biomedical Sciences, City University of Hong Kong , Hong Kong SAR, China
| | - Yingpeng Xie
- Department of Biomedical Sciences, City University of Hong Kong , Hong Kong SAR, China
| | - Yingchao Zhang
- Department of Biomedical Sciences, City University of Hong Kong , Hong Kong SAR, China
| | - Jingui Liu
- Department of Biomedical Sciences, City University of Hong Kong , Hong Kong SAR, China
| | - Yiqing Ding
- Department of Biomedical Sciences, City University of Hong Kong , Hong Kong SAR, China
| | - Min Wu
- Department of Biomedical Sciences, University of North Dakota , Grand Forks, North Dakota, USA
| | - Xin Wang
- Department of Biomedical Sciences, City University of Hong Kong , Hong Kong SAR, China
| | - Xin Deng
- Department of Biomedical Sciences, City University of Hong Kong , Hong Kong SAR, China.,Shenzhen Research Institute, City University of Hong Kong , Shenzhen, China
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Ayoub Moubareck C. Polymyxins and Bacterial Membranes: A Review of Antibacterial Activity and Mechanisms of Resistance. MEMBRANES 2020; 10:membranes10080181. [PMID: 32784516 PMCID: PMC7463838 DOI: 10.3390/membranes10080181] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 07/30/2020] [Accepted: 07/31/2020] [Indexed: 12/19/2022]
Abstract
Following their initial discovery in the 1940s, polymyxin antibiotics fell into disfavor due to their potential clinical toxicity, especially nephrotoxicity. However, the dry antibiotic development pipeline, together with the rising global prevalence of infections caused by multidrug-resistant (MDR) Gram-negative bacteria have both rejuvenated clinical interest in these polypeptide antibiotics. Parallel to the revival of their use, investigations into the mechanisms of action and resistance to polymyxins have intensified. With an initial known effect on biological membranes, research has uncovered the detailed molecular and chemical interactions that polymyxins have with Gram-negative outer membranes and lipopolysaccharide structure. In addition, genetic and epidemiological studies have revealed the basis of resistance to these agents. Nowadays, resistance to polymyxins in MDR Gram-negative pathogens is well elucidated, with chromosomal as well as plasmid-encoded, transferrable pathways. The aims of the current review are to highlight the important chemical, microbiological, and pharmacological properties of polymyxins, to discuss their mechanistic effects on bacterial membranes, and to revise the current knowledge about Gram-negative acquired resistance to these agents. Finally, recent research, directed towards new perspectives for improving these old agents utilized in the 21st century, to combat drug-resistant pathogens, is summarized.
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Kawano H, Suzuki-Minakuchi C, Sugiyama D, Watanabe N, Takahashi Y, Okada K, Nojiri H. A Novel Small RNA on the Pseudomonas putida KT2440 Chromosome Is Involved in the Fitness Cost Imposed by IncP-1 Plasmid RP4. Front Microbiol 2020; 11:1328. [PMID: 32655527 PMCID: PMC7324555 DOI: 10.3389/fmicb.2020.01328] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 05/25/2020] [Indexed: 12/12/2022] Open
Abstract
Plasmids can provide advantageous traits to host bacteria, although they may impose a fitness cost. Chromosome-encoded factors are important for regulating the expression of genes on plasmids, and host chromosomes may differ in terms of their interactions with a given plasmid. Accordingly, differences in fitness cost loading and compensatory co-evolution may occur for various host chromosome/plasmid combinations. However, the mechanisms of compensatory evolution are highly divergent and require further insights. Here, we reveal novel evolutionally mechanisms of Pseudomonas putida KT2440 to improve the fitness cost imposed by the incompatibility P-1 (IncP-1) multidrug resistance plasmid RP4. A mixed culture of RP4-harboring and -free KT2440 cells was serially transferred every 24 h under non-selective conditions. Initially, the proportion of RP4-harboring cells decreased rapidly, but it immediately recovered, suggesting that the fitness of RP4-harboring strains improved during cultivation. Larger-sized colonies appeared during 144-h mixed culture, and evolved strains isolated from larger-sized colonies showed higher growth rates and fitness than those of the ancestral strain. Whole-genome sequencing revealed that evolved strains had one of two mutations in the same intergenic region of the chromosome. Based on the research of another group, this region is predicted to contain a stress-inducible small RNA (sRNA). Identification of the transcriptional start site in this sRNA indicated that one mutation occurred within the sRNA region, whereas the other was in its promoter region. Quantitative reverse-transcription PCR showed that the expression of this sRNA was strongly induced by RP4 carriage in the ancestral strain but repressed in the evolved strains. When the sRNA region was overexpressed in the RP4-free strain, the fitness decreased, and the colony size became smaller. Using transcriptome analysis, we also showed that the genes involved in amino acid metabolism and stress responses were differentially transcribed by overexpression of the sRNA region. These results indicate that the RP4-inducible chromosomal sRNA was responsible for the fitness cost of RP4 on KT2440 cells, where this sRNA is of key importance in host evolution toward rapid amelioration of the cost.
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Affiliation(s)
- Hibiki Kawano
- Biotechnology Research Center, The University of Tokyo, Tokyo, Japan
| | - Chiho Suzuki-Minakuchi
- Biotechnology Research Center, The University of Tokyo, Tokyo, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo, Japan
| | - Daisuke Sugiyama
- Biotechnology Research Center, The University of Tokyo, Tokyo, Japan
| | - Natsuki Watanabe
- Biotechnology Research Center, The University of Tokyo, Tokyo, Japan
| | - Yurika Takahashi
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, Toyama, Japan
| | - Kazunori Okada
- Biotechnology Research Center, The University of Tokyo, Tokyo, Japan
| | - Hideaki Nojiri
- Biotechnology Research Center, The University of Tokyo, Tokyo, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo, Japan
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Gerdol M, Schmitt P, Venier P, Rocha G, Rosa RD, Destoumieux-Garzón D. Functional Insights From the Evolutionary Diversification of Big Defensins. Front Immunol 2020; 11:758. [PMID: 32425943 PMCID: PMC7203481 DOI: 10.3389/fimmu.2020.00758] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 04/03/2020] [Indexed: 12/14/2022] Open
Abstract
Big defensins are antimicrobial polypeptides believed to be the ancestors of β-defensins, the most evolutionary conserved family of host defense peptides (HDPs) in vertebrates. Nevertheless, big defensins underwent several independent gene loss events during animal evolution, being only retained in a limited number of phylogenetically distant invertebrates. Here, we explore the evolutionary history of this fascinating HDP family and investigate its patchy distribution in extant metazoans. We highlight the presence of big defensins in various classes of lophotrochozoans, as well as in a few arthropods and basal chordates (amphioxus), mostly adapted to life in marine environments. Bivalve mollusks often display an expanded repertoire of big defensin sequences, which appear to be the product of independent lineage-specific gene tandem duplications, followed by a rapid molecular diversification of newly acquired gene copies. This ongoing evolutionary process could underpin the simultaneous presence of canonical big defensins and non-canonical (β-defensin-like) sequences in some species. The big defensin genes of mussels and oysters, two species target of in-depth studies, are subjected to gene presence/absence variation (PAV), i.e., they can be present or absent in the genomes of different individuals. Moreover, big defensins follow different patterns of gene expression within a given species and respond differently to microbial challenges, suggesting functional divergence. Consistently, current structural data show that big defensin sequence diversity affects the 3D structure and biophysical properties of these polypeptides. We discuss here the role of the N-terminal hydrophobic domain, lost during evolution toward β-defensins, in the big defensin stability to high salt concentrations and its mechanism of action. Finally, we discuss the potential of big defensins as markers for animal health and for the nature-based design of novel therapeutics active at high salt concentrations.
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Affiliation(s)
- Marco Gerdol
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Paulina Schmitt
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Paola Venier
- Department of Biology, University of Padova, Padova, Italy
| | - Gustavo Rocha
- Laboratory of Immunology Applied to Aquaculture, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina, Florianópolis, Brazil
| | - Rafael Diego Rosa
- Laboratory of Immunology Applied to Aquaculture, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina, Florianópolis, Brazil
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The Efflux Pump MexXY/OprM Contributes to the Tolerance and Acquired Resistance of Pseudomonas aeruginosa to Colistin. Antimicrob Agents Chemother 2020; 64:AAC.02033-19. [PMID: 31964794 DOI: 10.1128/aac.02033-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 01/13/2020] [Indexed: 12/29/2022] Open
Abstract
The intrinsic resistance of Pseudomonas aeruginosa to polymyxins in part relies on the addition of 4-amino-4-deoxy-l-arabinose (Ara4N) molecules to the lipid A of lipopolysaccharide (LPS), through induction of operon arnBCADTEF-ugd (arn) expression. As demonstrated previously, at least three two-component regulatory systems (PmrAB, ParRS, and CprRS) are able to upregulate this operon when bacteria are exposed to colistin. In the present study, gene deletion experiments with the bioluminescent strain PAO1::lux showed that ParRS is a key element in the tolerance of P. aeruginosa to this last-resort antibiotic (i.e., resistance to early drug killing). Other loci of the ParR regulon, such as those encoding the efflux proteins MexXY (mexXY), the polyamine biosynthetic pathway PA4773-PA4774-PA4775, and Ara4N LPS modification process (arnBCADTEF-ugd), also contribute to the bacterial tolerance in an intricate way with ParRS. Furthermore, we found that both stable upregulation of the arn operon and drug-induced ParRS-dependent overexpression of the mexXY genes accounted for the elevated resistance of pmrB mutants to colistin. Deletion of the mexXY genes in a constitutively activated ParR mutant of PAO1 was associated with significantly increased expression of the genes arnA, PA4773, and pmrA in the absence of colistin exposure, thereby highlighting a functional link between the MexXY/OprM pump, the PA4773-PA4774-PA4775 pathway, and Ara4N-based modification of LPS. The role played by MexXY/OprM in the adaptation of P. aeruginosa to polymyxins opens new perspectives for restoring the susceptibility of resistant mutants through the use of efflux inhibitors.
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King MM, Kayastha BB, Franklin MJ, Patrauchan MA. Calcium Regulation of Bacterial Virulence. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:827-855. [PMID: 31646536 DOI: 10.1007/978-3-030-12457-1_33] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Calcium (Ca2+) is a universal signaling ion, whose major informational role shaped the evolution of signaling pathways, enabling cellular communications and responsiveness to both the intracellular and extracellular environments. Elaborate Ca2+ regulatory networks have been well characterized in eukaryotic cells, where Ca2+ regulates a number of essential cellular processes, ranging from cell division, transport and motility, to apoptosis and pathogenesis. However, in bacteria, the knowledge on Ca2+ signaling is still fragmentary. This is complicated by the large variability of environments that bacteria inhabit with diverse levels of Ca2+. Yet another complication arises when bacterial pathogens invade a host and become exposed to different levels of Ca2+ that (1) are tightly regulated by the host, (2) control host defenses including immune responses to bacterial infections, and (3) become impaired during diseases. The invading pathogens evolved to recognize and respond to the host Ca2+, triggering the molecular mechanisms of adhesion, biofilm formation, host cellular damage, and host-defense resistance, processes enabling the development of persistent infections. In this review, we discuss: (1) Ca2+ as a determinant of a host environment for invading bacterial pathogens, (2) the role of Ca2+ in regulating main events of host colonization and bacterial virulence, and (3) the molecular mechanisms of Ca2+ signaling in bacterial pathogens.
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Affiliation(s)
- Michelle M King
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Biraj B Kayastha
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Michael J Franklin
- Department of Microbiology and Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA
| | - Marianna A Patrauchan
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA.
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Abstract
Gram-negative carbapenem-resistant bacteria are a major threat to global health. The use of genome-wide screening approaches to probe for genes or mutations enabling resistance can lead to identification of molecular markers for diagnostics applications. We describe an approach called Mut-Seq that couples chemical mutagenesis and next-generation sequencing for studying resistance to imipenem in the Gram-negative bacteria Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The use of this approach highlighted shared and species-specific responses, and the role in resistance of a number of genes involved in membrane biogenesis, transcription, and signal transduction was functionally validated. Interestingly, some of the genes identified were previously considered promising therapeutic targets. Our genome-wide screen has the potential to be extended outside drug resistance studies and expanded to other organisms. Carbapenem-resistant Gram-negative bacteria are considered a major threat to global health. Imipenem (IMP) is used as a last line of treatment against these pathogens, but its efficacy is diminished by the emergence of resistance. We applied a whole-genome screen in Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa isolates that were submitted to chemical mutagenesis, selected for IMP resistance, and characterized by next-generation sequencing. A comparative analysis of IMP-resistant clones showed that most of the highly mutated genes shared by the three species encoded proteins involved in transcription or signal transduction. Of these, the rpoD gene was one of the most prevalent and an E. coli strain disrupted for rpoD displayed a 4-fold increase in resistance to IMP. E. coli and K. pneumoniae also specifically shared several mutated genes, most involved in membrane/cell envelope biogenesis, and the contribution in IMP susceptibility was experimentally proven for amidases, transferases, and transglycosidases. P. aeruginosa differed from the two Enterobacteriaceae isolates with two different resistance mechanisms, with one involving mutations in the oprD porin or, alternatively, in two-component systems. Our chemogenomic screen performed with the three species has highlighted shared and species-specific responses to IMP. IMPORTANCE Gram-negative carbapenem-resistant bacteria are a major threat to global health. The use of genome-wide screening approaches to probe for genes or mutations enabling resistance can lead to identification of molecular markers for diagnostics applications. We describe an approach called Mut-Seq that couples chemical mutagenesis and next-generation sequencing for studying resistance to imipenem in the Gram-negative bacteria Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The use of this approach highlighted shared and species-specific responses, and the role in resistance of a number of genes involved in membrane biogenesis, transcription, and signal transduction was functionally validated. Interestingly, some of the genes identified were previously considered promising therapeutic targets. Our genome-wide screen has the potential to be extended outside drug resistance studies and expanded to other organisms.
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Moffatt JH, Harper M, Boyce JD. Mechanisms of Polymyxin Resistance. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1145:55-71. [PMID: 31364071 DOI: 10.1007/978-3-030-16373-0_5] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Polymyxin antibiotics are increasingly being used as last-line therapeutic options against a number of multidrug resistant bacteria. These antibiotics show strong bactericidal activity against a range of Gram-negative bacteria, but with the increased use of these antibiotics resistant strains are emerging at an alarming rate. Furthermore, some Gram-negative species, such as Neisseria meningitidis, Proteus mirabilis and Burkholderia spp., are intrinsically resistant to the action of polymyxins. Most identified polymyxin resistance mechanisms in Gram-negative bacteria involve changes to the lipopolysaccharide (LPS) structure, as polymyxins initially interact with the negatively charged lipid A component of LPS. The controlled addition of positively charged residues such as 4-amino-L-arabinose, phosphoethanolamine and/or galactosamine to LPS results in a reduced negative charge on the bacterial surface and therefore reduced interaction between the polymyxin and the LPS. Polymyxin resistant species produce LPS that intrinsically contains one or more of these additions. While the genes necessary for most of these additions are chromosomally encoded, plasmid-borne phosphoethanolamine transferases (mcr-1 to mcr-8) have recently been identified and these plasmids threaten to increase the rate of dissemination of clinically relevant colistin resistance. Uniquely, Acinetobacter baumannii can also become highly resistant to polymyxins via spontaneous mutations in the lipid A biosynthesis genes lpxA, lpxC or lpxD such that they produce no LPS or lipid A. A range of other non-LPS-dependent polymyxin resistance mechanisms has also been identified in bacteria, but these generally result in only low levels of resistance. These include increased anionic capsular polysaccharide production in Klebsiella pneumoniae, expression of efflux systems such as MtrCDE in N. meningitidis, and altered expression of outer membrane proteins in a small number of species.
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Affiliation(s)
- Jennifer H Moffatt
- Biomedicine Discovery Institute, Infection and Immunity Program and Department of Microbiology, Monash University, Clayton, Australia
| | - Marina Harper
- Biomedicine Discovery Institute, Infection and Immunity Program and Department of Microbiology, Monash University, Clayton, Australia.,Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Australia
| | - John D Boyce
- Biomedicine Discovery Institute, Infection and Immunity Program and Department of Microbiology, Monash University, Clayton, Australia. .,Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Australia.
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A Family of Small Intrinsically Disordered Proteins Involved in Flagellum-Dependent Motility in Salmonella enterica. J Bacteriol 2018; 201:JB.00415-18. [PMID: 30373755 DOI: 10.1128/jb.00415-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 10/21/2018] [Indexed: 02/08/2023] Open
Abstract
By screening a collection of Salmonella mutants deleted for genes encoding small proteins of ≤60 amino acids, we identified three paralogous small genes (ymdF, STM14_1829, and yciG) required for wild-type flagellum-dependent swimming and swarming motility. The ymdF, STM14_1829, and yciG genes encode small proteins of 55, 60, and 60 amino acid residues, respectively. A bioinformatics analysis predicted that these small proteins are intrinsically disordered proteins, and circular dichroism analysis of purified recombinant proteins confirmed that all three proteins are unstructured in solution. A mutant deleted for STM14_1829 showed the most severe motility defect, indicating that among the three paralogs, STM14_1829 is a key protein required for wild-type motility. We determined that relative to the wild type, the expression of the flagellin protein FliC is lower in the ΔSTM14_1829 mutant due to the downregulation of the flhDC operon encoding the FlhDC master regulator. By comparing the gene expression profiles between the wild-type and ΔSTM14_1829 strains via RNA sequencing, we found that the gene encoding the response regulator PhoP is upregulated in the ΔSTM14_1829 mutant, suggesting the indirect repression of the flhDC operon by the activated PhoP. Homologs of STM14_1829 are conserved in a wide range of bacteria, including Escherichia coli and Pseudomonas aeruginosa We showed that the inactivation of STM14_1829 homologs in E. coli and P. aeruginosa also alters motility, suggesting that this family of small intrinsically disordered proteins may play a role in the cellular pathway(s) that affects motility.IMPORTANCE This study reports the identification of a novel family of small intrinsically disordered proteins that are conserved in a wide range of flagellated and nonflagellated bacteria. Although this study identifies the role of these small proteins in the scope of flagellum-dependent motility in Salmonella, they likely play larger roles in a more conserved cellular pathway(s) that indirectly affects flagellum expression in the case of motile bacteria. Small intrinsically disordered proteins have not been well characterized in prokaryotes, and the results of our study provide a basis for their detailed functional characterization.
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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: 978] [Impact Index Per Article: 163.0] [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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Breaking the Vicious Cycle of Antibiotic Killing and Regrowth of Biofilm-Residing Pseudomonas aeruginosa. Antimicrob Agents Chemother 2018; 62:AAC.01635-18. [PMID: 30297365 DOI: 10.1128/aac.01635-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 10/01/2018] [Indexed: 11/20/2022] Open
Abstract
Biofilm-residing bacteria embedded in an extracellular matrix are protected from diverse physicochemical insults. In addition to the general recalcitrance of biofilm bacteria, high bacterial loads in biofilm-associated infections significantly diminish the efficacy of antimicrobials due to a low per-cell antibiotic concentration. Accordingly, present antimicrobial treatment protocols that have been established to serve the eradication of acute infections fail to clear biofilm-associated chronic infections. In the present study, we applied automated confocal microscopy on Pseudomonas aeruginosa to monitor dynamic killing of biofilm-grown bacteria by tobramycin and colistin in real time. We revealed that the time required for surviving bacteria to repopulate the biofilm could be taken as a measure for effectiveness of the antimicrobial treatment. It depends on the (i) nature and concentration of the antibiotic, (ii) duration of antibiotic treatment, (iii) application as monotherapy or combination therapy, and (iv) interval of drug administration. The vicious cycle of killing and repopulation of biofilm bacteria could also be broken in an in vivo model system by applying successive antibiotic dosages at intervals that do not allow full reconstitution of the biofilm communities. Treatment regimens that consider the important aspects of antimicrobial killing kinetics bear the potential to improve control of biofilm regrowth. This is an important and underestimated factor that is bound to ensure sustainable treatment success of chronic infections.
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Molecular mechanisms of polymyxin resistance and detection of mcr genes. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2018; 163:28-38. [PMID: 30439931 DOI: 10.5507/bp.2018.070] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 10/26/2018] [Indexed: 12/12/2022] Open
Abstract
Antibiotic resistance is an ever-increasing global problem. Major commercial antibiotics often fail to fight common bacteria, and some pathogens have become multi-resistant. Polymyxins are potent bactericidal antibiotics against gram-negative bacteria. Known resistance to polymyxin includes intrinsic, mutational and adaptive mechanisms, with the recently described horizontally acquired resistance mechanisms. In this review, we present several strategies for bacteria to develop enhanced resistance to polymyxins, focusing on changes in the outer membrane, efflux and other resistance determinants. Better understanding of the genes involved in polymyxin resistance may pave the way for the development of new and effective antimicrobial agents. We also report novel in silico tested primers for PCR assay that may be able distinguish colistin-resistant isolates carrying the plasmid-encoded mcr genes and will assist in combating the spread of colistin resistance in bacteria.
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48
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Bassetti M, Vena A, Croxatto A, Righi E, Guery B. How to manage Pseudomonas aeruginosa infections. Drugs Context 2018; 7:212527. [PMID: 29872449 PMCID: PMC5978525 DOI: 10.7573/dic.212527] [Citation(s) in RCA: 409] [Impact Index Per Article: 68.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 04/03/2018] [Accepted: 04/04/2018] [Indexed: 02/07/2023] Open
Abstract
Infections with Pseudomonas aeruginosa have become a real concern in hospital-acquired infections, especially in critically ill and immunocompromised patients. The major problem leading to high mortality lies in the appearance of drug-resistant strains. Therefore, a vast number of approaches to develop novel anti-infectives is currently pursued. Diverse strategies range from killing (new antibiotics) to disarming (antivirulence) the pathogen. In this review, selected aspects of P. aeruginosa antimicrobial resistance and infection management will be addressed. Many studies have been performed to evaluate the risk factors for resistance and the potential consequences on mortality and attributable mortality. The review also looks at the mechanisms associated with resistance – P. aeruginosa is a pathogen presenting a large genome, and it can develop a large number of factors associated with antibiotic resistance involving almost all classes of antibiotics. Clinical approaches to patients with bacteremia, ventilator-associated pneumonia, urinary tract infections and skin soft tissue infections are discussed. Antibiotic combinations are reviewed as well as an analysis of pharmacokinetic and pharmacodynamic parameters to optimize P. aeruginosa treatment. Limitations of current therapies, the potential for alternative drugs and new therapeutic options are also discussed.
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Affiliation(s)
- Matteo Bassetti
- Infectious Diseases Clinic, Department of Medicine, University of Udine and Azienda Sanitaria Universitaria Integrata, Udine, Italy
| | - Antonio Vena
- Infectious Diseases Clinic, Department of Medicine, University of Udine and Azienda Sanitaria Universitaria Integrata, Udine, Italy
| | - Antony Croxatto
- Institute of Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Elda Righi
- Infectious Diseases Clinic, Department of Medicine, University of Udine and Azienda Sanitaria Universitaria Integrata, Udine, Italy
| | - Benoit Guery
- Infectious Diseases Service, Department of Medicine, University Hospital and University of Lausanne, Lausanne, Switzerland
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Gellatly SL, Bains M, Breidenstein EBM, Strehmel J, Reffuveille F, Taylor PK, Yeung ATY, Overhage J, Hancock REW. Novel roles for two-component regulatory systems in cytotoxicity and virulence-related properties in Pseudomonas aeruginosa. AIMS Microbiol 2018; 4:173-191. [PMID: 31294209 PMCID: PMC6605022 DOI: 10.3934/microbiol.2018.1.173] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 02/26/2018] [Indexed: 11/18/2022] Open
Abstract
The rapid adaptation of the opportunistic bacterial pathogen Pseudomonas aeruginosa to various growth modes and environmental conditions is controlled in part through diverse two-component regulatory systems. Some of these systems are well studied, but the majority are poorly characterized, even though it is likely that several of these systems contribute to virulence. Here, we screened all available strain PA14 mutants in 50 sensor kinases, 50 response regulators and 5 hybrid sensor/regulators, for contributions to cytotoxicity against cultured human bronchial epithelial cells, as assessed by the release of cytosolic lactate dehydrogenase. This enabled the identification of 8 response regulators and 3 sensor kinases that caused substantial decreases in cytotoxicity, and 5 response regulators and 8 sensor kinases that significantly increased cytotoxicity by 15-58% or more. These regulators were additionally involved in motility, adherence, type 3 secretion, production of cytotoxins, and the development of biofilms. Here we investigated in more detail the roles of FleSR, PilSR and WspR. Not all cognate pairs contributed to cytotoxicity (e.g. PhoPQ, PilSR) in the same way and some differences could be detected between the same mutants in PAO1 and PA14 strain backgrounds (e.g. FleSR, PhoPQ). This study highlights the potential importance of these regulators and their downstream targets on pathogenesis and demonstrates that cytotoxicity can be regulated by several systems and that their contributions are partly dependent on strain background.
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Affiliation(s)
- Shaan L Gellatly
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Manjeet Bains
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Elena B M Breidenstein
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Janine Strehmel
- Microbiology of Natural and Technical Interfaces Department, Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Fany Reffuveille
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Patrick K Taylor
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Amy T Y Yeung
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Joerg Overhage
- Microbiology of Natural and Technical Interfaces Department, Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
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50
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Bakthavatchalam YD, Pragasam AK, Biswas I, Veeraraghavan B. Polymyxin susceptibility testing, interpretative breakpoints and resistance mechanisms: An update. J Glob Antimicrob Resist 2018; 12:124-136. [DOI: 10.1016/j.jgar.2017.09.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 07/25/2017] [Accepted: 09/19/2017] [Indexed: 12/12/2022] Open
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