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David A, Tahrioui A, Duchesne R, Tareau AS, Maillot O, Barreau M, Feuilloley MGJ, Lesouhaitier O, Cornelis P, Bouffartigues E, Chevalier S. Membrane fluidity homeostasis is required for tobramycin-enhanced biofilm in Pseudomonas aeruginosa. Microbiol Spectr 2024; 12:e0230323. [PMID: 38411953 PMCID: PMC10986583 DOI: 10.1128/spectrum.02303-23] [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: 06/06/2023] [Accepted: 02/04/2024] [Indexed: 02/28/2024] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen, which causes chronic infections, especially in cystic fibrosis (CF) patients where it colonizes the lungs via the build-up of biofilms. Tobramycin, an aminoglycoside, is often used to treat P. aeruginosa infections in CF patients. Tobramycin at sub-minimal inhibitory concentrations enhances both biofilm biomass and thickness in vitro; however, the mechanism(s) involved are still unknown. Herein, we show that tobramycin increases the expression and activity of SigX, an extracytoplasmic sigma factor known to be involved in the biosynthesis of membrane lipids and membrane fluidity homeostasis. The biofilm enhancement by tobramycin is not observed in a sigX mutant, and the sigX mutant displays increased membrane stiffness. Remarkably, the addition of polysorbate 80 increases membrane fluidity of sigX-mutant cells in biofilm, restoring the tobramycin-enhanced biofilm formation. Our results suggest the involvement of membrane fluidity homeostasis in biofilm development upon tobramycin exposure.IMPORTANCEPrevious studies have shown that sub-lethal concentrations of tobramycin led to an increase biofilm formation in the case of infections with the opportunistic pathogen Pseudomonas aeruginosa. We show that the mechanism involved in this phenotype relies on the cell envelope stress response, triggered by the extracytoplasmic sigma factor SigX. This phenotype was abolished in a sigX-mutant strain. Remarkably, we show that increasing the membrane fluidity of the mutant strain is sufficient to restore the effect of tobramycin. Altogether, our data suggest the involvement of membrane fluidity homeostasis in biofilm development upon tobramycin exposure.
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Affiliation(s)
- Audrey David
- Unité de recherche Communication Bactérienne et Stratégies Anti-infectieuses, CBSA UR4312, Université de Rouen Normandie, Normandie Université, Evreux, France
- Fédération de Recherche Normande Sécurité Sanitaire, bien être, Aliment Durable (SéSAD), Evreux, France
| | - Ali Tahrioui
- Unité de recherche Communication Bactérienne et Stratégies Anti-infectieuses, CBSA UR4312, Université de Rouen Normandie, Normandie Université, Evreux, France
- Fédération de Recherche Normande Sécurité Sanitaire, bien être, Aliment Durable (SéSAD), Evreux, France
| | - Rachel Duchesne
- Unité de recherche Communication Bactérienne et Stratégies Anti-infectieuses, CBSA UR4312, Université de Rouen Normandie, Normandie Université, Evreux, France
- Fédération de Recherche Normande Sécurité Sanitaire, bien être, Aliment Durable (SéSAD), Evreux, France
| | - Anne-Sophie Tareau
- Unité de recherche Communication Bactérienne et Stratégies Anti-infectieuses, CBSA UR4312, Université de Rouen Normandie, Normandie Université, Evreux, France
- Fédération de Recherche Normande Sécurité Sanitaire, bien être, Aliment Durable (SéSAD), Evreux, France
| | - Olivier Maillot
- Unité de recherche Communication Bactérienne et Stratégies Anti-infectieuses, CBSA UR4312, Université de Rouen Normandie, Normandie Université, Evreux, France
- Fédération de Recherche Normande Sécurité Sanitaire, bien être, Aliment Durable (SéSAD), Evreux, France
| | - Magalie Barreau
- Unité de recherche Communication Bactérienne et Stratégies Anti-infectieuses, CBSA UR4312, Université de Rouen Normandie, Normandie Université, Evreux, France
- Fédération de Recherche Normande Sécurité Sanitaire, bien être, Aliment Durable (SéSAD), Evreux, France
| | - Marc G. J. Feuilloley
- Unité de recherche Communication Bactérienne et Stratégies Anti-infectieuses, CBSA UR4312, Université de Rouen Normandie, Normandie Université, Evreux, France
- Fédération de Recherche Normande Sécurité Sanitaire, bien être, Aliment Durable (SéSAD), Evreux, France
| | - Olivier Lesouhaitier
- Unité de recherche Communication Bactérienne et Stratégies Anti-infectieuses, CBSA UR4312, Université de Rouen Normandie, Normandie Université, Evreux, France
- Fédération de Recherche Normande Sécurité Sanitaire, bien être, Aliment Durable (SéSAD), Evreux, France
| | - Pierre Cornelis
- Unité de recherche Communication Bactérienne et Stratégies Anti-infectieuses, CBSA UR4312, Université de Rouen Normandie, Normandie Université, Evreux, France
- Fédération de Recherche Normande Sécurité Sanitaire, bien être, Aliment Durable (SéSAD), Evreux, France
| | - Emeline Bouffartigues
- Unité de recherche Communication Bactérienne et Stratégies Anti-infectieuses, CBSA UR4312, Université de Rouen Normandie, Normandie Université, Evreux, France
- Fédération de Recherche Normande Sécurité Sanitaire, bien être, Aliment Durable (SéSAD), Evreux, France
| | - Sylvie Chevalier
- Unité de recherche Communication Bactérienne et Stratégies Anti-infectieuses, CBSA UR4312, Université de Rouen Normandie, Normandie Université, Evreux, France
- Fédération de Recherche Normande Sécurité Sanitaire, bien être, Aliment Durable (SéSAD), Evreux, France
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Vohra M, Kour A, Kalia NP, Kumar M, Sharma S, Jaglan S, Kamath N, Sharma S. A comprehensive review of genomics, transcriptomics, proteomics, and metabolomic insights into the differentiation of Pseudomonas aeruginosa from the planktonic to biofilm state: A multi-omics approach. Int J Biol Macromol 2024; 257:128563. [PMID: 38070800 DOI: 10.1016/j.ijbiomac.2023.128563] [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: 07/20/2023] [Revised: 11/06/2023] [Accepted: 11/30/2023] [Indexed: 01/26/2024]
Abstract
Biofilm formation by Pseudomonas aeruginosa is primarily responsible for chronic wound and lung infections in humans. These infections are persistent owing to the biofilm's high tolerance to antimicrobials and constantly changing environmental factors. Understanding the mechanism governing biofilm formation can help to develop therapeutics explicitly directed against the molecular markers responsible for this process. After numerous years of research, many genes responsible for both in vitro and in vivo biofilm development remain unidentified. However, there is no "all in one" complete in vivo or in vitro biofilm model. Recent findings imply that the shift from planktonic bacteria to biofilms is a complicated and interrelated differentiation process. Research on the applications of omics technologies in P. aeruginosa biofilm development is ongoing, and these approaches hold great promise for expanding our knowledge of the mechanisms of biofilm formation. This review discusses the different factors that affect biofilm formation and compares P. aeruginosa biofilm formation using the omics approaches targeting essential biological macromolecules, such as DNA, RNA, Protein, and metabolome. Furthermore, we have outlined the application of currently available omics tools, such as genomics, proteomics, metabolomics, transcriptomics, and integrated multi-omics methodologies, to understand the differential gene expression (biofilm vs. planktonic bacteria) of P. aeruginosa biofilms.
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Affiliation(s)
- Mustafa Vohra
- Department of Medical Laboratory Science, Lovely Professional University, Punjab 144411, India; Department of Microbiology, Shri Vinoba Bhave Civil Hospital, Silvassa 396230, India
| | - Avleen Kour
- Department of Medical Laboratory Science, Lovely Professional University, Punjab 144411, India
| | - Nitin Pal Kalia
- Department of Biological Sciences (Pharmacology & Toxicology), National Institute of Pharmaceutical Education and Research (NIPER), Balanagar, Hyderabad, Telangana 500037, India
| | - Manoj Kumar
- Maternal and Child Health Program, Research Department, Sidra Medicine, Doha 122104, Qatar
| | - Sarika Sharma
- Department of Sponsored Research, Division of Research & Development, Lovely Professional University, India
| | - Sundeep Jaglan
- Fermentation & Microbial Biotechnology Division, CSIR-Indian Institute of Integrative Medicine, Jammu 180016, J&K, India
| | - Narayan Kamath
- Department of Microbiology, Shri Vinoba Bhave Civil Hospital, Silvassa 396230, India; Department of Microbiology, NAMO Medical Education and Research Institute, Silvassa 396230, India
| | - Sandeep Sharma
- Department of Medical Laboratory Science, Lovely Professional University, Punjab 144411, India.
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Cleaver L, Garnett JA. How to study biofilms: technological advancements in clinical biofilm research. Front Cell Infect Microbiol 2023; 13:1335389. [PMID: 38156318 PMCID: PMC10753778 DOI: 10.3389/fcimb.2023.1335389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 11/30/2023] [Indexed: 12/30/2023] Open
Abstract
Biofilm formation is an important survival strategy commonly used by bacteria and fungi, which are embedded in a protective extracellular matrix of organic polymers. They are ubiquitous in nature, including humans and other animals, and they can be surface- and non-surface-associated, making them capable of growing in and on many different parts of the body. Biofilms are also complex, forming polymicrobial communities that are difficult to eradicate due to their unique growth dynamics, and clinical infections associated with biofilms are a huge burden in the healthcare setting, as they are often difficult to diagnose and to treat. Our understanding of biofilm formation and development is a fast-paced and important research focus. This review aims to describe the advancements in clinical biofilm research, including both in vitro and in vivo biofilm models, imaging techniques and techniques to analyse the biological functions of the biofilm.
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Affiliation(s)
- Leanne Cleaver
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King’s College London, London, United Kingdom
| | - James A. Garnett
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King’s College London, London, United Kingdom
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4
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Wiesmann CL, Wang NR, Zhang Y, Liu Z, Haney CH. Origins of symbiosis: shared mechanisms underlying microbial pathogenesis, commensalism and mutualism of plants and animals. FEMS Microbiol Rev 2023; 47:fuac048. [PMID: 36521845 PMCID: PMC10719066 DOI: 10.1093/femsre/fuac048] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 12/07/2022] [Accepted: 12/09/2022] [Indexed: 12/17/2023] Open
Abstract
Regardless of the outcome of symbiosis, whether it is pathogenic, mutualistic or commensal, bacteria must first colonize their hosts. Intriguingly, closely related bacteria that colonize diverse hosts with diverse outcomes of symbiosis have conserved host-association and virulence factors. This review describes commonalities in the process of becoming host associated amongst bacteria with diverse lifestyles. Whether a pathogen, commensal or mutualist, bacteria must sense the presence of and migrate towards a host, compete for space and nutrients with other microbes, evade the host immune system, and change their physiology to enable long-term host association. We primarily focus on well-studied taxa, such as Pseudomonas, that associate with diverse model plant and animal hosts, with far-ranging symbiotic outcomes. Given the importance of opportunistic pathogens and chronic infections in both human health and agriculture, understanding the mechanisms that facilitate symbiotic relationships between bacteria and their hosts will help inform the development of disease treatments for both humans, and the plants we eat.
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Affiliation(s)
- Christina L Wiesmann
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Nicole R Wang
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Yue Zhang
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Zhexian Liu
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Cara H Haney
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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Lichtenberg M, Coenye T, Parsek MR, Bjarnsholt T, Jakobsen TH. What's in a name? Characteristics of clinical biofilms. FEMS Microbiol Rev 2023; 47:fuad050. [PMID: 37656883 PMCID: PMC10503651 DOI: 10.1093/femsre/fuad050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 08/06/2023] [Accepted: 08/30/2023] [Indexed: 09/03/2023] Open
Abstract
In vitro biofilms are communities of microbes with unique features compared to individual cells. Biofilms are commonly characterized by physical traits like size, adhesion, and a matrix made of extracellular substances. They display distinct phenotypic features, such as metabolic activity and antibiotic tolerance. However, the relative importance of these traits depends on the environment and bacterial species. Various mechanisms enable biofilm-associated bacteria to withstand antibiotics, including physical barriers, physiological adaptations, and changes in gene expression. Gene expression profiles in biofilms differ from individual cells but, there is little consensus among studies and so far, a 'biofilm signature transcriptome' has not been recognized. Additionally, the spatial and temporal variability within biofilms varies greatly depending on the system or environment. Despite all these variable conditions, which produce very diverse structures, they are all noted as biofilms. We discuss that clinical biofilms may differ from those grown in laboratories and found in the environment and discuss whether the characteristics that are commonly used to define and characterize biofilms have been shown in infectious biofilms. We emphasize that there is a need for a comprehensive understanding of the specific traits that are used to define bacteria in infections as clinical biofilms.
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Affiliation(s)
- Mads Lichtenberg
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium
| | - Matthew R Parsek
- Department of Microbiology, University of Washington School of Medicine, 1705 NE Pacific St., WA 98195 Seattle, United States
| | - Thomas Bjarnsholt
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
- Department of Clinical Microbiology, Copenhagen University Hospital, Ole Maaløes vej 26, 2100 Copenhagen, Denmark
| | - Tim Holm Jakobsen
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
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Sauer K. Biofilms - Life upon First Contact and Beyond. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:1. [PMID: 37613027 DOI: 10.1093/micmic/ozad067.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Karin Sauer
- Department of Biological Sciences, Binghamton University, State University of New York, Binghamton, NY, United States
- Binghamton Biofilm Research Center, Binghamton University, State University of New York, Binghamton, NY, United States
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7
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Kaleta MF, Sauer K. MoaB1 Homologs Contribute to Biofilm Formation and Motility by Pseudomonas aeruginosa and Escherichia coli. J Bacteriol 2023; 205:e0000423. [PMID: 37098964 PMCID: PMC10210980 DOI: 10.1128/jb.00004-23] [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: 01/03/2023] [Accepted: 03/27/2023] [Indexed: 04/27/2023] Open
Abstract
moaB homologs, encoding the molybdopterin biosynthetic protein B1, have been reported to be expressed under anoxic conditions and during biofilm growth in various microorganisms; however, little is known about MoaB's function. Here, we demonstrate that in Pseudomonas aeruginosa, MoaB1 (PA3915) contributes to biofilm-related phenotypes. Specifically, moaB1 expression is induced in biofilms, and insertional inactivation of moaB1 reduced biofilm biomass accumulation and pyocyanin production while enhancing swarming motility, and pyoverdine abundance without affecting attachment, swimming motility, or c-di-GMP levels. Inactivation of the highly conserved E. coli homolog of moaB1, moaBEc, likewise coincided with reduced biofilm biomass accumulation. In turn, heterologous expression of moaBEc restored biofilm formation and swarming motility by the P. aeruginosa moaB1 mutant to wild-type levels. Moreover, MoaB1 was found to interact with other conserved biofilm-associated proteins, PA2184 and PA2146, as well as the sensor-kinase SagS. However, despite the interaction, MoaB1 failed to restore SagS-dependent expression of brlR encoding the transcriptional regulator BrlR, and inactivation of moaB1 or moaBEc had no effect on the antibiotic susceptibility phenotype of biofilms formed by P. aeruginosa and E. coli, respectively. While our findings did not establish a link between MoaB1 and molybdenum cofactor biosynthesis, they suggest that MoaB1 homologs contribute to biofilm-associated phenotypes across species boundaries, possibly hinting at the existence of a previously undescribed conserved biofilm pathway. IMPORTANCE Proteins contributing to the biogenesis of molybdenum cofactors have been characterized; however, the role of the molybdopterin biosynthetic protein B1 (MoaB1) has remained elusive, and solid evidence to support its role in biosynthesis of molybdenum cofactor is lacking. Here, we demonstrate that, in Pseudomonas aeruginosa, MoaB1 (PA3915) contributes to biofilm-related phenotypes in a manner that does not support a role of MoaB1 in the biosynthesis of molybdenum cofactors.
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Affiliation(s)
- Matthew F. Kaleta
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Karin Sauer
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
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8
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Wang T, Shen P, He Y, Zhang Y, Liu J. Spatial transcriptome uncovers rich coordination of metabolism in E. coli K12 biofilm. Nat Chem Biol 2023:10.1038/s41589-023-01282-w. [PMID: 37055614 DOI: 10.1038/s41589-023-01282-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Accepted: 02/02/2023] [Indexed: 04/15/2023]
Abstract
Microbial communities often display region-specific properties, which give rise to complex interactions and emergent behaviors that are critical to the homeostasis and stress response of the communities. However, systems-level understanding of these properties still remains elusive. In this study, we established RAINBOW-seq and profiled the transcriptome of Escherichia coli biofilm communities with high spatial resolution and high gene coverage. We uncovered three modes of community-level coordination, including cross-regional resource allocation, local cycling and feedback signaling, which were mediated by strengthened transmembrane transport and spatially specific activation of metabolism. As a consequence of such coordination, the nutrient-limited region of the community maintained an unexpectedly high level of metabolism, enabling it to express many signaling genes and functionally unknown genes with potential sociality functions. Our work provides an extended understanding of the metabolic interplay in biofilms and presents a new approach of investigating complex interactions in bacterial communities on the systems level.
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Affiliation(s)
- Tianmin Wang
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Ping Shen
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
| | - Yihui He
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
| | - Yuzhen Zhang
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Jintao Liu
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China.
- Tsinghua-Peking Center for Life Sciences, Beijing, China.
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9
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The biofilm life cycle: expanding the conceptual model of biofilm formation. Nat Rev Microbiol 2022; 20:608-620. [PMID: 35922483 PMCID: PMC9841534 DOI: 10.1038/s41579-022-00767-0] [Citation(s) in RCA: 256] [Impact Index Per Article: 128.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2022] [Indexed: 01/18/2023]
Abstract
Bacterial biofilms are often defined as communities of surface-attached bacteria and are typically depicted with a classic mushroom-shaped structure characteristic of Pseudomonas aeruginosa. However, it has become evident that this is not how all biofilms develop, especially in vivo, in clinical and industrial settings, and in the environment, where biofilms often are observed as non-surface-attached aggregates. In this Review, we describe the origin of the current five-step biofilm development model and why it fails to capture many aspects of bacterial biofilm physiology. We aim to present a simplistic developmental model for biofilm formation that is flexible enough to include all the diverse scenarios and microenvironments where biofilms are formed. With this new expanded, inclusive model, we hereby introduce a common platform for developing an understanding of biofilms and anti-biofilm strategies that can be tailored to the microenvironment under investigation.
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10
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Lu Y, Cai WJ, Ren Z, Han P. The Role of Staphylococcal Biofilm on the Surface of Implants in Orthopedic Infection. Microorganisms 2022; 10:1909. [PMID: 36296183 PMCID: PMC9612000 DOI: 10.3390/microorganisms10101909] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/11/2022] [Accepted: 09/20/2022] [Indexed: 08/27/2023] Open
Abstract
Despite advanced implant sterilization and aseptic surgical techniques, implant-associated infection remains a major challenge for orthopedic surgeries. The subject of bacterial biofilms is receiving increasing attention, probably as a result of the wide acknowledgement of the ubiquity of biofilms in the clinical environment, as well as the extreme difficulty in eradicating them. Biofilm can be defined as a structured microbial community of cells that are attached to a substratum and embedded in a matrix of extracellular polymeric substances (EPS) that they have produced. Biofilm development has been proposed as occurring in a multi-step process: (i) attachment and adherence, (ii) accumulation/maturation due to cellular aggregation and EPS production, and (iii) biofilm detachment (also called dispersal) of bacterial cells. In all these stages, characteristic proteinaceous and non-proteinaceous compounds are expressed, and their expression is strictly controlled. Bacterial biofilm formation around implants shelters the bacteria and encourages the persistence of infection, which could lead to implant failure and osteomyelitis. These complications need to be treated by major revision surgeries and extended antibiotic therapies, which could lead to high treatment costs and even increase mortality. Effective preventive and therapeutic measures to reduce risks for implant-associated infections are thus in urgent need.
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Affiliation(s)
| | | | | | - Pei Han
- Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
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11
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Nutrient Sensing and Biofilm Modulation: The Example of L-arginine in Pseudomonas. Int J Mol Sci 2022; 23:ijms23084386. [PMID: 35457206 PMCID: PMC9028604 DOI: 10.3390/ijms23084386] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/12/2022] [Accepted: 04/13/2022] [Indexed: 12/01/2022] Open
Abstract
Bacterial biofilm represents a multicellular community embedded within an extracellular matrix attached to a surface. This lifestyle confers to bacterial cells protection against hostile environments, such as antibiotic treatment and host immune response in case of infections. The Pseudomonas genus is characterised by species producing strong biofilms difficult to be eradicated and by an extraordinary metabolic versatility which may support energy and carbon/nitrogen assimilation under multiple environmental conditions. Nutrient availability can be perceived by a Pseudomonas biofilm which, in turn, readapts its metabolism to finally tune its own formation and dispersion. A growing number of papers is now focusing on the mechanism of nutrient perception as a possible strategy to weaken the biofilm barrier by environmental cues. One of the most important nutrients is amino acid L-arginine, a crucial metabolite sustaining bacterial growth both as a carbon and a nitrogen source. Under low-oxygen conditions, L-arginine may also serve for ATP production, thus allowing bacteria to survive in anaerobic environments. L-arginine has been associated with biofilms, virulence, and antibiotic resistance. L-arginine is also a key precursor of regulatory molecules such as polyamines, whose involvement in biofilm homeostasis is reported. Given the biomedical and biotechnological relevance of biofilm control, the state of the art on the effects mediated by the L-arginine nutrient on biofilm modulation is presented, with a special focus on the Pseudomonas biofilm. Possible biotechnological and biomedical applications are also discussed.
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12
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Liu XY, Guo S, Bocklitz T, Rösch P, Popp J, Yu HQ. Nondestructive 3D imaging and quantification of hydrated biofilm matrix by confocal Raman microscopy coupled with non-negative matrix factorization. WATER RESEARCH 2022; 210:117973. [PMID: 34959065 DOI: 10.1016/j.watres.2021.117973] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 11/30/2021] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
Biofilms are ubiquitous in natural and engineered environments and of great importance in drinking water distribution and biological wastewater treatment systems. Simultaneously acquiring the chemical and structural information of the hydrated biofilm matrix is essential for the cognition and regulation of biofilms in the environmental field. However, the complexity of samples and the limited approaches prevent a holistic understanding of the biofilm matrix. In this work, an approach based on the confocal Raman mapping technique integrated with non-negative matrix factorization (NMF) analysis was developed to probe the hydrated biofilm matrix in situ. The flexibility of the NMF analysis was utilized to subtract the undesired water background signal and resolve the meaningful biological components from Raman spectra of the hydrated biofilms. Diverse chemical components such as proteins, bacterial cells, glycolipids and polyhydroxyalkanoates (PHA) were unraveled within the distinct Pseudomonas spp. biofilm matrices, and the corresponding 3-dimensional spatial organization was visualized and quantified. Of these components, glycolipids and PHA were unique to the P. aeruginosa and P. putida biofilm matrix, respectively. Furthermore, their high abundances in the lower region of the biofilm matrix were found to be related to the specific physiological functions and surrounding microenvironments. Overall, the results demonstrate that our NMF Raman mapping method could serve as a powerful tool complementary to the conventional approaches for identifying and visualizing the chemical components in the biofilm matrix. This work may facilitate the online characterization of the biofilm matrix widely present in the environment and advance the fundamental understanding of biofilm.
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Affiliation(s)
- Xiao-Yang Liu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China; School of Energy & Environmental Engineering, Hebei University of Technology, Tianjin 300130, China; Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, Jena D-07743, Germany; InfectoGnostics Research Campus Jena, Philosophenweg 7, Jena D-07743, Germany
| | - Shuxia Guo
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, Jena D-07743, Germany; Leibniz Institute of Photonic Technology Jena - Member of the Research Alliance "Leibniz Health Technologies", Albert-Einstein-Strasse 9, Jena D-07745, Germany
| | - Thomas Bocklitz
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, Jena D-07743, Germany; Leibniz Institute of Photonic Technology Jena - Member of the Research Alliance "Leibniz Health Technologies", Albert-Einstein-Strasse 9, Jena D-07745, Germany
| | - Petra Rösch
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, Jena D-07743, Germany; InfectoGnostics Research Campus Jena, Philosophenweg 7, Jena D-07743, Germany
| | - Jürgen Popp
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, Jena D-07743, Germany; InfectoGnostics Research Campus Jena, Philosophenweg 7, Jena D-07743, Germany; Center for Sepsis Control and Care (CSCC), Jena University Hospital, Am Klinikum 1, Jena D-07743, Germany; Leibniz Institute of Photonic Technology Jena - Member of the Research Alliance "Leibniz Health Technologies", Albert-Einstein-Strasse 9, Jena D-07745, Germany.
| | - Han-Qing Yu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China.
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13
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Rodriguez-Urretavizcaya B, Pascual N, Pastells C, Martin-Gomez MT, Vilaplana L, Marco MP. Diagnosis and Stratification of Pseudomonas aeruginosa Infected Patients by Immunochemical Quantitative Determination of Pyocyanin From Clinical Bacterial Isolates. Front Cell Infect Microbiol 2022; 11:786929. [PMID: 34970510 PMCID: PMC8712664 DOI: 10.3389/fcimb.2021.786929] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 11/12/2021] [Indexed: 12/04/2022] Open
Abstract
The development of a highly sensitive, specific, and reliable immunochemical assay to detect pyocyanin (PYO), one of the most important virulence factors (VFs) of Pseudomonas aeruginosa, is here reported. The assay uses a high-affinity monoclonal antibody (mAb; C.9.1.9.1.1.2.2.) raised against 1-hydroxyphenazine (1-OHphz) hapten derivatives (PC1; a 1:1 mixture of 9-hydroxy- and 6-hydroxy-phenazine-2-carobxylic acids). Selective screening using PYO and 1-OHphz on several cloning cycles allowed the selection of a clone able to detect PYO at low concentration levels. The microplate-based ELISA developed is able to achieve a limit of detection (LoD) of 0.07 nM, which is much lower than the concentrations reported to be found in clinical samples (130 μM in sputa and 2.8 μM in ear secretions). The ELISA has allowed the investigation of the release kinetics of PYO and 1-OHphz (the main metabolite of PYO) of clinical isolates obtained from P. aeruginosa-infected patients and cultured in Mueller–Hinton medium. Significant differences have been found between clinical isolates obtained from patients with an acute or a chronic infection (~6,000 nM vs. ~8 nM of PYO content, respectively) corroborated by the analysis of PYO/1-OHphz levels released by 37 clinical isolates obtained from infected patients at different stages. In all cases, the levels of 1-OHphz were much lower than those of PYO (at the highest levels 6,000 nM vs. 300 nM for PYO vs. 1-OHphz, respectively). The results found point to a real potential of PYO as a biomarker of P. aeruginosa infection and the possibility to use such VF also as a biomarker for patient stratification[2] and for an effective management of these kinds of infections.
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Affiliation(s)
- Barbara Rodriguez-Urretavizcaya
- Nanobiotechnology for Diagnostics (Nb4D), Institute of Advanced Chemistry of Catalonia, Institute for Advanced Chemistry of Catalonia (IQAC)-Spanish National Research Council (CSIC), Barcelona, Spain.,Centro de Investigación Biomédica en Red (CIBER) de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, Spain
| | - Nuria Pascual
- Nanobiotechnology for Diagnostics (Nb4D), Institute of Advanced Chemistry of Catalonia, Institute for Advanced Chemistry of Catalonia (IQAC)-Spanish National Research Council (CSIC), Barcelona, Spain.,Centro de Investigación Biomédica en Red (CIBER) de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, Spain
| | - Carme Pastells
- Nanobiotechnology for Diagnostics (Nb4D), Institute of Advanced Chemistry of Catalonia, Institute for Advanced Chemistry of Catalonia (IQAC)-Spanish National Research Council (CSIC), Barcelona, Spain.,Centro de Investigación Biomédica en Red (CIBER) de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, Spain
| | | | - Lluïsa Vilaplana
- Nanobiotechnology for Diagnostics (Nb4D), Institute of Advanced Chemistry of Catalonia, Institute for Advanced Chemistry of Catalonia (IQAC)-Spanish National Research Council (CSIC), Barcelona, Spain.,Centro de Investigación Biomédica en Red (CIBER) de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, Spain
| | - Maria-Pilar Marco
- Nanobiotechnology for Diagnostics (Nb4D), Institute of Advanced Chemistry of Catalonia, Institute for Advanced Chemistry of Catalonia (IQAC)-Spanish National Research Council (CSIC), Barcelona, Spain.,Centro de Investigación Biomédica en Red (CIBER) de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, Spain
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14
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Matilla MA, Velando F, Monteagudo-Cascales E, Krell T. Flagella, Chemotaxis and Surface Sensing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:185-221. [DOI: 10.1007/978-3-031-08491-1_7] [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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15
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Park S, Sauer K. Controlling Biofilm Development Through Cyclic di-GMP Signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:69-94. [PMID: 36258069 PMCID: PMC9891824 DOI: 10.1007/978-3-031-08491-1_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The cyclic di-GMP (c-di-GMP) second messenger represents a signaling system that regulates many bacterial behaviors and is of key importance for driving the lifestyle switch between motile loner cells and biofilm formers. This review provides an up-to-date summary of c-di-GMP pathways connected to biofilm formation by the opportunistic pathogen P. aeruginosa. Emphasis will be on the timing of c-di-GMP production over the course of biofilm formation, to highlight non-uniform and hierarchical increases in c-di-GMP levels, as well as biofilm growth conditions that do not conform with our current model of c-di-GMP.
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Affiliation(s)
- Soyoung Park
- Department of Biological Sciences, Binghamton University, Binghamton, NY, USA
- Binghamton Biofilm Research Center (BBRC), Binghamton University, Binghamton, NY, USA
| | - Karin Sauer
- Department of Biological Sciences, Binghamton University, Binghamton, NY, USA.
- Binghamton Biofilm Research Center (BBRC), Binghamton University, Binghamton, NY, USA.
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16
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Park S, Sauer K. SagS and its unorthodox contributions to Pseudomonas aeruginosa biofilm development. Biofilm 2021; 3:100059. [PMID: 34729470 PMCID: PMC8543379 DOI: 10.1016/j.bioflm.2021.100059] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 10/18/2021] [Accepted: 10/19/2021] [Indexed: 01/16/2023] Open
Abstract
The Pseudomonas aeruginosa orphan sensor SagS (PA2824) was initially reported as one of three orphan sensor kinases capable of activating HptB, a component of the HptB signaling pathway that intersects with the Gac/Rsm signaling pathway and fine-tunes P. aeruginosa motility and pathogenesis. Since then, this orphan sensor has been reported to be involved in other, unorthodox signaling pathways serving additional functions. The present review is aimed at summarizing the various functions of SagS, with an emphasis on its toggle or dual switch functions, and highlighting the role of SagS as a hub at which the various signaling pathways intersect, to regulate the transition from the planktonic to the sessile mode of growth, as well as the transition of surface-associated cells to a drug tolerant state.
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Affiliation(s)
- Soyoung Park
- Department of Biological Sciences, Binghamton University, Binghamton, NY, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, NY, USA
| | - Karin Sauer
- Department of Biological Sciences, Binghamton University, Binghamton, NY, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, NY, USA
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17
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Jeckel H, Drescher K. Advances and opportunities in image analysis of bacterial cells and communities. FEMS Microbiol Rev 2021; 45:fuaa062. [PMID: 33242074 PMCID: PMC8371272 DOI: 10.1093/femsre/fuaa062] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 11/20/2020] [Indexed: 12/16/2022] Open
Abstract
The cellular morphology and sub-cellular spatial structure critically influence the function of microbial cells. Similarly, the spatial arrangement of genotypes and phenotypes in microbial communities has important consequences for cooperation, competition, and community functions. Fluorescence microscopy techniques are widely used to measure spatial structure inside living cells and communities, which often results in large numbers of images that are difficult or impossible to analyze manually. The rapidly evolving progress in computational image analysis has recently enabled the quantification of a large number of properties of single cells and communities, based on traditional analysis techniques and convolutional neural networks. Here, we provide a brief introduction to core concepts of automated image processing, recent software tools and how to validate image analysis results. We also discuss recent advances in image analysis of microbial cells and communities, and how these advances open up opportunities for quantitative studies of spatiotemporal processes in microbiology, based on image cytometry and adaptive microscope control.
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Affiliation(s)
- Hannah Jeckel
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 16, 35043 Marburg, Germany
- Department of Physics, Philipps-Universität Marburg, Karl-von-Frisch-Str. 16, 35043 Marburg, Germany
| | - Knut Drescher
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 16, 35043 Marburg, Germany
- Department of Physics, Philipps-Universität Marburg, Karl-von-Frisch-Str. 16, 35043 Marburg, Germany
- Synmikro Center for Synthetic Microbiology, Karl-von-Frisch-Str. 16, 35043 Marburg, Germany
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18
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A regulatory network involving Rpo, Gac and Rsm for nitrogen-fixing biofilm formation by Pseudomonas stutzeri. NPJ Biofilms Microbiomes 2021; 7:54. [PMID: 34210981 PMCID: PMC8249394 DOI: 10.1038/s41522-021-00230-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 06/16/2021] [Indexed: 02/06/2023] Open
Abstract
Biofilm and nitrogen fixation are two competitive strategies used by many plant-associated bacteria; however, the mechanisms underlying the formation of nitrogen-fixing biofilms remain largely unknown. Here, we examined the roles of multiple signalling systems in the regulation of biofilm formation by root-associated diazotrophic P. stutzeri A1501. Physiological analysis, construction of mutant strains and microscale thermophoresis experiments showed that RpoN is a regulatory hub coupling nitrogen fixation and biofilm formation by directly activating the transcription of pslA, a major gene involved in the synthesis of the Psl exopolysaccharide component of the biofilm matrix and nifA, the transcriptional activator of nif gene expression. Genetic complementation studies and determination of the copy number of transcripts by droplet digital PCR confirmed that the regulatory ncRNA RsmZ serves as a signal amplifier to trigger biofilm formation by sequestering the translational repressor protein RsmA away from pslA and sadC mRNAs, the latter of which encodes a diguanylate cyclase that synthesises c-di-GMP. Moreover, RpoS exerts a braking effect on biofilm formation by transcriptionally downregulating RsmZ expression, while RpoS expression is repressed posttranscriptionally by RsmA. These findings provide mechanistic insights into how the Rpo/Gac/Rsm regulatory networks fine-tune nitrogen-fixing biofilm formation in response to the availability of nutrients.
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19
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Ozer E, Yaniv K, Chetrit E, Boyarski A, Meijler MM, Berkovich R, Kushmaro A, Alfonta L. An inside look at a biofilm: Pseudomonas aeruginosa flagella biotracking. SCIENCE ADVANCES 2021; 7:eabg8581. [PMID: 34117070 PMCID: PMC8195488 DOI: 10.1126/sciadv.abg8581] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/28/2021] [Indexed: 05/28/2023]
Abstract
The opportunistic pathogen, Pseudomonas aeruginosa, a flagellated bacterium, is one of the top model organisms for biofilm studies. To elucidate the location of bacterial flagella throughout the biofilm life cycle, we developed a new flagella biotracking tool. Bacterial flagella were site-specifically labeled via genetic code expansion. This enabled us to track bacterial flagella during biofilm maturation. Live flagella imaging revealed the presence and synthesis of flagella throughout the biofilm life cycle. To study the possible role of flagella in a biofilm, we produced a flagella knockout strain and compared its biofilm to that of the wild-type strain. Results showed a one order of magnitude stronger biofilm structure in the wild type in comparison with the flagella knockout strain. This suggests a possible structural role for flagella in a biofilm, conceivably as a scaffold. Our findings suggest a new model for biofilm maturation dynamic which underscores the importance of direct evidence from within the biofilm.
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Affiliation(s)
- Eden Ozer
- Department of Life Sciences, Ben-Gurion University of the Negev, PO Box 653, Beer-Sheva 8410501, Israel
| | - Karin Yaniv
- Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben-Gurion University of the Negev, PO Box 653, Beer-Sheva 8410501, Israel
| | - Einat Chetrit
- Department of Chemical Engineering, Ben-Gurion University of the Negev, PO Box 653, Beer-Sheva 8410501, Israel
| | - Anastasya Boyarski
- Department of Chemistry, Ben-Gurion University of the Negev, PO Box 653, Beer-Sheva 8410501, Israel
| | - Michael M Meijler
- Department of Chemistry, Ben-Gurion University of the Negev, PO Box 653, Beer-Sheva 8410501, Israel
- National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, PO Box 653, Beer-Sheva 8410501, Israel
| | - Ronen Berkovich
- Department of Chemical Engineering, Ben-Gurion University of the Negev, PO Box 653, Beer-Sheva 8410501, Israel
- Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, PO Box 653, Beer-Sheva 8410501, Israel
| | - Ariel Kushmaro
- Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben-Gurion University of the Negev, PO Box 653, Beer-Sheva 8410501, Israel.
- Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, PO Box 653, Beer-Sheva 8410501, Israel
| | - Lital Alfonta
- Department of Life Sciences, Ben-Gurion University of the Negev, PO Box 653, Beer-Sheva 8410501, Israel.
- Department of Chemistry, Ben-Gurion University of the Negev, PO Box 653, Beer-Sheva 8410501, Israel
- Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, PO Box 653, Beer-Sheva 8410501, Israel
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20
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Heacock-Kang Y, McMillan IA, Norris MH, Sun Z, Zarzycki-Siek J, Bluhm AP, Cabanas D, Norton RE, Ketheesan N, Miller JF, Schweizer HP, Hoang TT. The Burkholderia pseudomallei intracellular 'TRANSITome'. Nat Commun 2021; 12:1907. [PMID: 33772012 PMCID: PMC7998038 DOI: 10.1038/s41467-021-22169-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 02/26/2021] [Indexed: 01/01/2023] Open
Abstract
Prokaryotic cell transcriptomics has been limited to mixed or sub-population dynamics and individual cells within heterogeneous populations, which has hampered further understanding of spatiotemporal and stage-specific processes of prokaryotic cells within complex environments. Here we develop a 'TRANSITomic' approach to profile transcriptomes of single Burkholderia pseudomallei cells as they transit through host cell infection at defined stages, yielding pathophysiological insights. We find that B. pseudomallei transits through host cells during infection in three observable stages: vacuole entry; cytoplasmic escape and replication; and membrane protrusion, promoting cell-to-cell spread. The B. pseudomallei 'TRANSITome' reveals dynamic gene-expression flux during transit in host cells and identifies genes that are required for pathogenesis. We find several hypothetical proteins and assign them to virulence mechanisms, including attachment, cytoskeletal modulation, and autophagy evasion. The B. pseudomallei 'TRANSITome' provides prokaryotic single-cell transcriptomics information enabling high-resolution understanding of host-pathogen interactions.
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Affiliation(s)
- Yun Heacock-Kang
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Ian A McMillan
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Michael H Norris
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
- Department of Geography and Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Zhenxin Sun
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Jan Zarzycki-Siek
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Andrew P Bluhm
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
- Department of Geography and Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Darlene Cabanas
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Robert E Norton
- Townsville Hospital, Townsville, QLD, Australia
- Faculty of Medicine, University of Queensland, Brisbane, Australia
| | - Natkunam Ketheesan
- Science and Technology, University of New England, New South Wales, Australia
| | - Jeff F Miller
- Department of Microbiology, Immunology, and Molecular Genetics, and the California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Herbert P Schweizer
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - Tung T Hoang
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA.
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21
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Pseudomonas aeruginosa as a Model To Study Chemosensory Pathway Signaling. Microbiol Mol Biol Rev 2021; 85:85/1/e00151-20. [PMID: 33441490 DOI: 10.1128/mmbr.00151-20] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bacteria have evolved a variety of signal transduction mechanisms that generate different outputs in response to external stimuli. Chemosensory pathways are widespread in bacteria and are among the most complex signaling mechanisms, requiring the participation of at least six proteins. These pathways mediate flagellar chemotaxis, in addition to controlling alternative functions such as second messenger levels or twitching motility. The human pathogen Pseudomonas aeruginosa has four different chemosensory pathways that carry out different functions and are stimulated by signal binding to 26 chemoreceptors. Recent research employing a diverse range of experimental approaches has advanced enormously our knowledge on these four pathways, establishing P. aeruginosa as a primary model organism in this field. In the first part of this article, we review data on the function and physiological relevance of chemosensory pathways as well as their involvement in virulence, whereas the different transcriptional and posttranscriptional regulatory mechanisms that govern pathway function are summarized in the second part. The information presented will be of help to advance the understanding of pathway function in other organisms.
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22
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Fogen D. The Role of PaFicT in Pseudomonas aeruginosa Persister Cell Formation. INTERNATIONAL JOURNAL OF MOLECULAR AND CELLULAR MEDICINE 2021; 10:277-287. [PMID: 35875333 PMCID: PMC9273157 DOI: 10.22088/ijmcm.bums.10.4.277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 04/09/2022] [Indexed: 11/04/2022]
Abstract
The opportunistic pathogen Pseudomonas aeruginosa (Pa) is a major concern for immunocompromised and cystic fibrosis patients. Chronic lung infections caused by Pa are generally considered incurable, in part, due to the bacteria's ability to form persister cells. These variants are categorized as being phenotypically dormant and highly tolerant to antibiotic treatment. Currently, the mechanisms involved in Pa persister cell formation is poorly understood. One promising candidate is the Pa filamentation induced by cAMP (FIC) domain containing toxin (PaFicT), which like other FIC toxins transiently inhibits cell growth. Genetic knockout and complementation by single copy chromosomal insertion was used to characterize paficT involvement in Pa persister cell formation. Toxicity and the PaFicT active site were examined by overexpression of wild-type and mutant protein variants. Antibiotic tolerance of PaFicT-induced Pa persister cells, was measured by minimum inhibitory concentration (MIC) analysis and compared to parental mostly non-persister populations. Deletion of paficT resulted in a 7.2-fold reduction in persister cell formation, which was fully complemented by re-insertion of the gene. Expression of PaFicT significantly increased persister cell formation by 5.9-fold, and this phenotype required a functional FIC active site motif. Unlike growing cell populations, PaFicT-induced persister cells were unaffected by 4 h treatment with 10 × MIC meropenem and showed an increased survival of 6.2 × 105-fold to tobramycin under the same conditions. Alternatively, survival of both persisters and parental, mostly non-persister, populations were below detectable levels following amikacin treatment. Results indicate a potential major involvement of PaFicT in Pa persister cell formation and multidrug tolerance.
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Affiliation(s)
- Dawson Fogen
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA.,Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA.,Corresponding author: Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA.
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23
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Abstract
The formation of microbial biofilms enables single planktonic cells to assume a multicellular mode of growth. During dispersion, the final step of the biofilm life cycle, single cells egress from the biofilm to resume a planktonic lifestyle. As the planktonic state is considered to be more vulnerable to antimicrobial agents and immune responses, dispersion is being considered a promising avenue for biofilm control. In this Review, we discuss conditions that lead to dispersion and the mechanisms by which native and environmental cues contribute to dispersion. We also explore recent findings on the role of matrix degradation in the dispersion process, and the distinct phenotype of dispersed cells. Last, we discuss the translational and therapeutic potential of dispersing bacteria during infection.
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Affiliation(s)
- Kendra P Rumbaugh
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, USA
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, USA
- Department of the TTUHSC Surgery Burn Center of Research Excellence, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Karin Sauer
- Department of Biological Sciences, Binghamton University, Binghamton, NY, USA.
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, NY, USA.
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24
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Sarkar S. Release mechanisms and molecular interactions of Pseudomonas aeruginosa extracellular DNA. Appl Microbiol Biotechnol 2020; 104:6549-6564. [PMID: 32500267 DOI: 10.1007/s00253-020-10687-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/10/2020] [Accepted: 05/17/2020] [Indexed: 12/18/2022]
Abstract
Pseudomonas aeruginosa infection is a significant threat for clinicians. Increasing incidents of resistant biofilm infection result in high mortality rates worldwide. There is a considerable current interest in the field of extracellular DNA (eDNA)-mediated P. aeruginosa biofilm formation. eDNA acts as a glue to make biofilm more stable. This review focuses on the diverse mechanisms and factors, which enhance the eDNA release into the extracellular milieu. Furthermore, eDNA-mediated molecular interactions within the biofilm are emphasized. In addition, drug resistance mechanisms due to the versatility of eDNA are discussed. Spatial physiological diversity is expected due to different metabolic activity of bacterial subpopulation present in P. aeruginosa biofilm layers. In P. aeruginosa, eDNA release is accomplished by cell lysis and OMVs (outer membrane vesicles). eDNA release is a spontaneous and multifactorial process, which may be accomplished by PQS, pyocyanin, and lambda prophage induction. Hydrogen peroxide and pyocin trigger cell death, which may facilitate eDNA release. Lung mucosa of cystic fibrosis patients is enriched with eDNA, which acidifies biofilm and develops P. aeruginosa resistance to aminoglycosides. Further studies on spatial and molecular characterization of bacterial subpopulation in biofilm will shed light on eDNA-biofilm interaction more precisely.Key Points• Extracellular DNA (eDNA) is a key component of Pseudomonas aeruginosa biofilm.• P. aeruginosa eDNA acts as a glue to make biofilm more stronger.• Bacterial cell death or lysis may be the potential way to release P. aeruginosa eDNA into extracellular milieu.• P. aeruginosa eDNA contributes to develop resistance to antimicrobials.
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Affiliation(s)
- Subendu Sarkar
- Department of Surgery, University School of Medicine, Indiana University, Indianapolis, IN, 46202, USA. .,Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA.
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25
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Hermansen GMM, Sazinas P, Kofod D, Millard A, Andersen PS, Jelsbak L. Transcriptomic profiling of interacting nasal staphylococci species reveals global changes in gene and non-coding RNA expression. FEMS Microbiol Lett 2019; 365:4794939. [PMID: 29325106 DOI: 10.1093/femsle/fny004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 01/08/2018] [Indexed: 12/14/2022] Open
Abstract
Interspecies interactions between bacterial pathogens and the commensal microbiota can influence disease outcome. In the nasal cavities, Staphylococcus epidermidis has been shown to be a determining factor for Staphylococcus aureus colonization and biofilm formation. However, the interaction between S. epidermidis and S. aureus has mainly been described by phenotypic analysis, and little is known about how this interaction modulates gene expression. This study aimed to determine the interactome of nasal S. aureus and S. epidermidis isolates to understand the molecular effect of interaction. After whole-genome sequencing of two nasal staphylococcal isolates, an agar-based RNA sequencing setup was utilized to identify interaction-induced transcriptional alterations in surface-associated populations. Our results revealed differential expression of several virulence genes in both species. We also identified putative non-coding RNAs (ncRNAs) and, interestingly, detected a putative ncRNA transcribed antisense to esp, the serine protease of S. epidermidis, that has previously been shown to inhibit nasal colonization of S. aureus. In our study, the gene encoding Esp and the antisense ncRNA are both downregulated during interaction with S. aureus. Our findings contribute to a better understanding of pathogen physiology in the context of interactions with the commensal microbiota, and may provide targets for future therapeutics.
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Affiliation(s)
- Grith M M Hermansen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs Lyngby, Denmark
| | - Pavelas Sazinas
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs Lyngby, Denmark
| | - Ditte Kofod
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs Lyngby, Denmark
| | - Andrew Millard
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 7RH, UK
| | - Paal Skytt Andersen
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Lars Jelsbak
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs Lyngby, Denmark
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26
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Bisht K, Wakeman CA. Discovery and Therapeutic Targeting of Differentiated Biofilm Subpopulations. Front Microbiol 2019; 10:1908. [PMID: 31507548 PMCID: PMC6718512 DOI: 10.3389/fmicb.2019.01908] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Accepted: 08/05/2019] [Indexed: 12/21/2022] Open
Abstract
The association of microorganisms into biofilms produces functionally organized microbial structures that promote community survival in a wide range of environments. Much like when individual cells within a multicellular organism express different genes from the same DNA blueprint, individual microbial cells located within different regions of a biofilm structure can exhibit distinct genetic programs. These spatially defined regions of physiologically differentiated cells are reminiscent of the role of tissues in multicellular organisms, with specific subpopulations in the microbial community serving defined roles to promote the overall health of the biofilm. The functions of these subpopulations are quite diverse and can range from dormant cells that can withstand antibiotic onslaughts to cells actively producing extracellular polymeric substances providing integrity to the entire community. The purpose of this review is to discuss the diverse roles of subpopulations in the stability and function of clonal biofilms, the methods for studying these subpopulations, and the ways these subpopulations can potentially be exploited for therapeutic intervention.
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Affiliation(s)
- Karishma Bisht
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, United States
| | - Catherine Ann Wakeman
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, United States
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Two Regulators, PA3898 and PA2100, Modulate the Pseudomonas aeruginosa Multidrug Resistance MexAB-OprM and EmrAB Efflux Pumps and Biofilm Formation. Antimicrob Agents Chemother 2018; 62:AAC.01459-18. [PMID: 30297364 DOI: 10.1128/aac.01459-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 09/29/2018] [Indexed: 11/20/2022] Open
Abstract
It is generally believed that the Pseudomonas aeruginosa biofilm matrix itself acts as a molecular sieve or sink that contributes to significant levels of drug resistance, but it is becoming more apparent that multidrug efflux pumps induced during biofilm growth significantly enhance resistance levels. We present here a novel transcriptional regulator, PA3898, which controls biofilm formation and multidrug efflux pumps in P. aeruginosa A mutant of this regulator significantly reduced the ability of P. aeruginosa to produce biofilm in vitro and affected its in vivo fitness and pathogenesis in Drosophila melanogaster and BALB/c mouse lung infection models. Transcriptome analysis revealed that PA3898 modulates essential virulence genes/pathways, including multidrug efflux pumps and phenazine biosynthesis. Chromatin immunoprecipitation sequencing (ChIP-seq) identified its DNA binding sequences and confirmed that PA3898 directly interacts with promoter regions of four genes/operons, two of which are mexAB-oprM and phz2 Coimmunoprecipitation revealed a regulatory partner of PA3898 as PA2100, and both are required for binding to DNA in electrophoretic mobility shift assays. PA3898 and PA2100 were given the names MdrR1 and MdrR2, respectively, as novel repressors of the mexAB-oprM multidrug efflux operon and activators for another multidrug efflux pump, EmrAB. The interaction between MdrR1 and MdrR2 at the promoter regions of their regulons was further characterized via localized surface plasmon resonance and DNA footprinting. These regulators directly repress the mexAB-oprM operon, independent of its well-established MexR regulator. Mutants of mdrR1 and mdrR2 caused increased resistance to multiple antibiotics in P. aeruginosa, validating the significance of these newly discovered regulators.
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Heacock-Kang Y, Zarzycki-Siek J, Sun Z, Poonsuk K, Bluhm AP, Cabanas D, Fogen D, McMillan IA, Chuanchuen R, Hoang TT. Novel dual regulators of Pseudomonas aeruginosa essential for productive biofilms and virulence. Mol Microbiol 2018; 109:401-414. [PMID: 29995308 PMCID: PMC6158065 DOI: 10.1111/mmi.14063] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/25/2018] [Indexed: 01/14/2023]
Abstract
Gene regulation network in Pseudomonas aeruginosa is complex. With a relatively large genome (6.2 Mb), there is a significant portion of genes that are proven or predicted to be transcriptional regulators. Many of these regulators have been shown to play important roles in biofilm formation and maintenance. In this study, we present a novel transcriptional regulator, PA1226, which modulates biofilm formation and virulence in P. aeruginosa. Mutation in the gene encoding this regulator abolished the ability of P. aeruginosa to produce biofilms in vitro, without any effect on the planktonic growth. This regulator is also essential for the in vivo fitness and pathogenesis in both Drosophila melanogaster and BALB/c mouse lung infection models. Transcriptome analysis revealed that PA1226 regulates many essential virulence genes/pathways, including those involved in alginate, pili, and LPS biosynthesis. Genes/operons directly regulated by PA1226 and potential binding sequences were identified via ChIP-seq. Attempts to confirm the binding sequences by electrophoretic mobility shift assay led to the discovery of a co-regulator, PA1413, via co-immunoprecipitation assay. PA1226 and PA1413 were shown to bind collaboratively to the promoter regions of their regulons. A model is proposed, summarizing our finding on this novel dual-regulation system.
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Affiliation(s)
- Yun Heacock-Kang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Jan Zarzycki-Siek
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Zhenxin Sun
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Kanchana Poonsuk
- Department of Veterinary Public Health, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Andrew P Bluhm
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Darlene Cabanas
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Dawson Fogen
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Ian A McMillan
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Rungtip Chuanchuen
- Department of Veterinary Public Health, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Tung T Hoang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
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29
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Mastropasqua MC, Lamont I, Martin LW, Reid DW, D'Orazio M, Battistoni A. Efficient zinc uptake is critical for the ability of Pseudomonas aeruginosa to express virulence traits and colonize the human lung. J Trace Elem Med Biol 2018; 48:74-80. [PMID: 29773197 DOI: 10.1016/j.jtemb.2018.03.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 01/31/2018] [Accepted: 03/08/2018] [Indexed: 02/03/2023]
Abstract
We have recently shown that Pseudomonas aeruginosa, an opportunistic pathogen that chronically infects the lungs of patients with cystic fibrosis (CF) and other forms of lung disease, is extremely efficient in recruiting zinc from the environment and that this capability is required for its ability to cause acute lung infections in mice. To verify that P. aeruginosa faces zinc shortage when colonizing the lungs of human patients, we analyzed the expression of three genes that are highly induced under conditions of zinc deficiency (zrmA, dksA2 and rpmE2), in bacteria in the sputum of patients with inflammatory lung disease. All three genes were expressed in all the analyzed sputum samples to a level much higher than that of bacteria grown in zinc-containing laboratory medium, supporting the hypothesis that P. aeruginosa is under zinc starvation during lung infections. We also found that the expression of several virulence traits that play a central role in the ability of P. aeruginosa to colonize the lung is affected by disruption of the most important zinc importing systems. Virulence features dependent on zinc intake include swarming and swimming motility and the ability to form biofilms. Furthermore, alterations in zinc assimilation interfere with the synthesis of the siderophore pyoverdine, suggesting that zinc recruitment could modulate iron uptake and affect siderophore-mediated cell signaling. Our results reveal that zinc uptake is likely to play a key role in the ability of P. aeruginosa to cause chronic lung infections and strongly modulates critical virulence traits of the pathogen. Taking into account the recent discovery that zinc uptake in P. aeruginosa is promoted by the release of a small molecular weight molecule showing high affinity for zinc, our data suggest novel and effective possibilities to control lung infections by these bacteria.
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Affiliation(s)
| | - Iain Lamont
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Lois W Martin
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - David W Reid
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia; The Prince Charles Hospital, Brisbane, Queensland, Australia
| | - Melania D'Orazio
- Department of Biology, University of Rome Tor Vergata, Rome, Italy
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Zheng R, Feng X, Wei X, Pan X, Liu C, Song R, Jin Y, Bai F, Jin S, Wu W, Cheng Z. PutA Is Required for Virulence and Regulated by PruR in Pseudomonas aeruginosa. Front Microbiol 2018; 9:548. [PMID: 29632523 PMCID: PMC5879082 DOI: 10.3389/fmicb.2018.00548] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 03/09/2018] [Indexed: 01/08/2023] Open
Abstract
Pseudomonas aeruginosa, a Gram-negative opportunistic pathogenic bacterium, causes acute and chronic infections. Upon entering the host, P. aeruginosa alters global gene expression to adapt to host environment and avoid clearance by the host immune system. Proline utilization A (PutA) is a bifunctional enzyme, which converts proline to glutamate. Here we report that PutA was required for the virulence of P. aeruginosa in a murine acute pneumonia model. A putA mutant was more susceptible to oxidative stress compared to the wild type strain. An AraC/XylS family protein, PruR, directly bound to the upstream of −35 box in the putA promoter and activated putA expression. High concentration of proline in bacteria up-regulated pruR expression, which led to the activation of putA expression. As a feedback regulation, glutamate produced by PutA released PruR from the putA promoter and turned off the putA expression. PruR affected bacterial virulence through the regulation of the putA expression. Altogether, these data are the first to reveal that PutA plays an important role in the pathogenesis of P. aeruginosa, as well as to describe the genetic regulation of PutA in P. aeruginosa.
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Affiliation(s)
- Ruiping Zheng
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Xuemei Feng
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Xueying Wei
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Xiaolei Pan
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Chang Liu
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Ruopu Song
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yongxin Jin
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Fang Bai
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Shouguang Jin
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, United States
| | - Weihui Wu
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Zhihui Cheng
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
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31
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Pseudomonas aeruginosa Biofilm Antibiotic Resistance Gene ndvB Expression Requires the RpoS Stationary-Phase Sigma Factor. Appl Environ Microbiol 2018; 84:AEM.02762-17. [PMID: 29352081 DOI: 10.1128/aem.02762-17] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 01/11/2018] [Indexed: 01/21/2023] Open
Abstract
Chronic, biofilm-based bacterial infections are exceptionally difficult to eradicate due to the high degree of antibiotic recalcitrance exhibited by cells in biofilm communities. In the opportunistic pathogen Pseudomonas aeruginosa, biofilm recalcitrance is multifactorial and arises in part from the preferential expression of resistance genes in biofilms compared to exponential-phase planktonic cells. One such mechanism involves ndvB, which we have previously shown to be expressed specifically in biofilms. In this study, we investigated the regulatory basis of this lifestyle-specific expression by developing an unstable green fluorescent protein (GFP) transcriptional reporter to observe the expression pattern of ndvB We found that in addition to its expression in biofilms, ndvB was upregulated in planktonic cells as they enter stationary phase. The transcription of ndvB in both growth phases was shown to be dependent on the stationary-phase sigma factor RpoS, and mutation of a putative RpoS binding site in the ndvB promoter abolished the activity of the promoter in stationary-phase cells. Overall, we have expanded our understanding of the temporal expression of ndvB in P. aeruginosa and have uncovered a regulatory basis for its growth phase-dependent expression.IMPORTANCE Bacterial biofilms are more resistant to antibiotics than free-living planktonic cells, and understanding the mechanistic basis of this resistance can inform treatments of biofilm-based infections. In addition to chemical and structural barriers that can inhibit antibiotic entry, the upregulation of specific genes in biofilms contributes to the resistance. We investigated this biofilm-specific gene induction by examining expression patterns of ndvB, a gene involved in biofilm resistance of the opportunistic pathogen Pseudomonas aeruginosa We characterized ndvB expression in planktonic and biofilm growth conditions with an unstable green fluorescent protein (GFP) reporter and found that the expression of ndvB in biofilms is dependent on the stationary-phase sigma factor RpoS. Overall, our results support the physiological similarity between biofilms and stationary-phase cells and suggest that the induction of some stationary-phase genes in biofilms may contribute to their increased antibiotic resistance.
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Antibiotic Persistence as a Metabolic Adaptation: Stress, Metabolism, the Host, and New Directions. Pharmaceuticals (Basel) 2018; 11:ph11010014. [PMID: 29389876 PMCID: PMC5874710 DOI: 10.3390/ph11010014] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 01/25/2018] [Accepted: 01/27/2018] [Indexed: 12/16/2022] Open
Abstract
Persistence is a phenomenon during which a small fraction of a total bacterial population survives treatment with high concentrations of antibiotics for an extended period of time. In conjunction with biofilms, antibiotic persisters represent a major cause of recalcitrant and recurring infections, resulting in significant morbidity and mortality. In this review, we discuss the clinical significance of persister cells and the central role of bacterial metabolism in their formation, specifically with respect to carbon catabolite repression, sugar metabolism, and growth regulation. Additionally, we will examine persister formation as an evolutionary strategy used to tolerate extended periods of stress and discuss some of the response mechanisms implicated in their formation. To date, the vast majority of the mechanistic research examining persistence has been conducted in artificial in vitro environments that are unlikely to be representative of host conditions. Throughout this review, we contextualize the existing body of literature by discussing how in vivo conditions may create ecological niches that facilitate the development of persistence. Lastly, we identify how the development of next-generation sequencing and other “big data” tools may enable researchers to examine persistence mechanisms within the host to expand our understanding of their clinical importance.
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Chang CY. Surface Sensing for Biofilm Formation in Pseudomonas aeruginosa. Front Microbiol 2018; 8:2671. [PMID: 29375533 PMCID: PMC5767216 DOI: 10.3389/fmicb.2017.02671] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 12/21/2017] [Indexed: 11/13/2022] Open
Abstract
Aggregating and forming biofilms on biotic or abiotic surfaces are ubiquitous bacterial behaviors under various conditions. In clinical settings, persistent presence of biofilms increases the risks of healthcare-associated infections and imposes huge healthcare and economic burdens. Bacteria within biofilms are protected from external damage and attacks from the host immune system and can exchange genomic information including antibiotic-resistance genes. Dispersed bacterial cells from attached biofilms on medical devices or host tissues may also serve as the origin of further infections. Understanding how bacteria develop biofilms is pertinent to tackle biofilm-associated infections and transmission. Biofilms have been suggested as a continuum of growth modes for adapting to different environments, initiating from bacterial cells sensing their attachment to a surface and then switching cellular physiological status for mature biofilm development. It is crucial to understand bacterial gene regulatory networks and decision-making processes for biofilm formation upon initial surface attachment. Pseudomonas aeruginosa is one of the model microorganisms for studying bacterial population behaviors. Several hypotheses and studies have suggested that extracellular macromolecules and appendages play important roles in bacterial responses to the surface attachment. Here, I review recent studies on potential molecular mechanisms and signal transduction pathways for P. aeruginosa surface sensing.
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Affiliation(s)
- Chien-Yi Chang
- School of Chemistry and Biosciences, University of Bradford, Bradford, United Kingdom
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