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Hibbert T, Krpetic Z, Latimer J, Leighton H, McHugh R, Pottenger S, Wragg C, James CE. Antimicrobials: An update on new strategies to diversify treatment for bacterial infections. Adv Microb Physiol 2024; 84:135-241. [PMID: 38821632 DOI: 10.1016/bs.ampbs.2023.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2024]
Abstract
Ninety-five years after Fleming's discovery of penicillin, a bounty of antibiotic compounds have been discovered, modified, or synthesised. Diversification of target sites, improved stability and altered activity spectra have enabled continued antibiotic efficacy, but overwhelming reliance and misuse has fuelled the global spread of antimicrobial resistance (AMR). An estimated 1.27 million deaths were attributable to antibiotic resistant bacteria in 2019, representing a major threat to modern medicine. Although antibiotics remain at the heart of strategies for treatment and control of bacterial diseases, the threat of AMR has reached catastrophic proportions urgently calling for fresh innovation. The last decade has been peppered with ground-breaking developments in genome sequencing, high throughput screening technologies and machine learning. These advances have opened new doors for bioprospecting for novel antimicrobials. They have also enabled more thorough exploration of complex and polymicrobial infections and interactions with the healthy microbiome. Using models of infection that more closely resemble the infection state in vivo, we are now beginning to measure the impacts of antimicrobial therapy on host/microbiota/pathogen interactions. However new approaches are needed for developing and standardising appropriate methods to measure efficacy of novel antimicrobial combinations in these contexts. A battery of promising new antimicrobials is now in various stages of development including co-administered inhibitors, phages, nanoparticles, immunotherapy, anti-biofilm and anti-virulence agents. These novel therapeutics need multidisciplinary collaboration and new ways of thinking to bring them into large scale clinical use.
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Affiliation(s)
- Tegan Hibbert
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences (IVES), University of Liverpool, Liverpool, UK
| | - Zeljka Krpetic
- School of Science, Engineering, and Environment, University of Salford, Salford, UK
| | - Joe Latimer
- School of Science, Engineering, and Environment, University of Salford, Salford, UK
| | - Hollie Leighton
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences (IVES), University of Liverpool, Liverpool, UK
| | - Rebecca McHugh
- School of Infection and Immunity, University of Glasgow, Glasgow, UK
| | - Sian Pottenger
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences (IVES), University of Liverpool, Liverpool, UK
| | - Charlotte Wragg
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences (IVES), University of Liverpool, Liverpool, UK
| | - Chloë E James
- School of Science, Engineering, and Environment, University of Salford, Salford, UK.
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Grandy S, Scur M, Dolan K, Nickerson R, Cheng Z. Using model systems to unravel host-Pseudomonas aeruginosa interactions. Environ Microbiol 2023; 25:1765-1784. [PMID: 37290773 DOI: 10.1111/1462-2920.16440] [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: 01/30/2023] [Accepted: 05/29/2023] [Indexed: 06/10/2023]
Abstract
Using model systems in infection biology has led to the discoveries of many pathogen-encoded virulence factors and critical host immune factors to fight pathogenic infections. Studies of the remarkable Pseudomonas aeruginosa bacterium that infects and causes disease in hosts as divergent as humans and plants afford unique opportunities to shed new light on virulence strategies and host defence mechanisms. One of the rationales for using model systems as a discovery tool to characterise bacterial factors driving human infection outcomes is that many P. aeruginosa virulence factors are required for pathogenesis in diverse different hosts. On the other side, many host signalling components, such as the evolutionarily conserved mitogen-activated protein kinases, are involved in immune signalling in a diverse range of hosts. Some model organisms that have less complex immune systems also allow dissection of the direct impacts of innate immunity on host defence without the interference of adaptive immunity. In this review, we start with discussing the occurrence of P. aeruginosa in the environment and the ability of this bacterium to cause disease in various hosts as a natural opportunistic pathogen. We then summarise the use of some model systems to study host defence and P. aeruginosa virulence.
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Affiliation(s)
- Shannen Grandy
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Michal Scur
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Kathleen Dolan
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Rhea Nickerson
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Zhenyu Cheng
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, 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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Role of Efflux Pumps on Antimicrobial Resistance in Pseudomonas aeruginosa. Int J Mol Sci 2022; 23:ijms232415779. [PMID: 36555423 PMCID: PMC9779380 DOI: 10.3390/ijms232415779] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 12/02/2022] [Accepted: 12/05/2022] [Indexed: 12/15/2022] Open
Abstract
Antimicrobial resistance is an old and silent pandemic. Resistant organisms emerge in parallel with new antibiotics, leading to a major global public health crisis over time. Antibiotic resistance may be due to different mechanisms and against different classes of drugs. These mechanisms are usually found in the same organism, giving rise to multidrug-resistant (MDR) and extensively drug-resistant (XDR) bacteria. One resistance mechanism that is closely associated with the emergence of MDR and XDR bacteria is the efflux of drugs since the same pump can transport different classes of drugs. In Gram-negative bacteria, efflux pumps are present in two configurations: a transmembrane protein anchored in the inner membrane and a complex formed by three proteins. The tripartite complex has a transmembrane protein present in the inner membrane, a periplasmic protein, and a porin associated with the outer membrane. In Pseudomonas aeruginosa, one of the main pathogens associated with respiratory tract infections, four main sets of efflux pumps have been associated with antibiotic resistance: MexAB-OprM, MexXY, MexCD-OprJ, and MexEF-OprN. In this review, the function, structure, and regulation of these efflux pumps in P. aeruginosa and their actions as resistance mechanisms are discussed. Finally, a brief discussion on the potential of efflux pumps in P. aeruginosa as a target for new drugs is presented.
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Barton TE, Frost F, Fothergill JL, Neill DR. Challenges and opportunities in the development of novel antimicrobial therapeutics for cystic fibrosis. J Med Microbiol 2022; 71. [PMID: 36748497 DOI: 10.1099/jmm.0.001643] [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: 12/24/2022] Open
Abstract
Chronic respiratory infection is the primary driver of mortality in individuals with cystic fibrosis (CF). Existing drug screening models utilised in preclinical antimicrobial development are unable to mimic the complex CF respiratory environment. Consequently, antimicrobials showing promising activity in preclinical models often fail to translate through to clinical efficacy in people with CF. Model systems used in CF anti-infective drug discovery and development range from antimicrobial susceptibility testing in nutrient broth, through to 2D and 3D in vitro tissue culture systems and in vivo models. No single model fully recapitulates every key aspect of the CF lung. To improve the outcomes of people with CF (PwCF) it is necessary to develop a set of preclinical models that collectively recapitulate the CF respiratory environment to a high degree of accuracy. Models must be validated for their ability to mimic aspects of the CF lung and associated lung infection, through evaluation of biomarkers that can also be assessed following treatment in the clinic. This will give preclinical models greater predictive power for identification of antimicrobials with clinical efficacy. The landscape of CF is changing, with the advent of modulator therapies that correct the function of the CFTR protein, while antivirulence drugs and phage therapy are emerging alternative treatments to chronic infection. This review discusses the challenges faced in current antimicrobial development pipelines, including the advantages and disadvantages of current preclinical models and the impact of emerging treatments.
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Affiliation(s)
- Thomas E Barton
- Department of Clinical Infection, Microbiology and Immunology, University of Liverpool, Ronald Ross Building, 8 West Derby Street, Liverpool, L69 7BE, UK
| | - Frederick Frost
- Adult Cystic Fibrosis Centre, Liverpool Heart & Chest Hospital NHS Foundation Trust, Liverpool, UK.,Liverpool Centre for Cardiovascular Sciences, University of Liverpool, Liverpool, UK
| | - Joanne L Fothergill
- Department of Clinical Infection, Microbiology and Immunology, University of Liverpool, Ronald Ross Building, 8 West Derby Street, Liverpool, L69 7BE, UK
| | - Daniel R Neill
- Department of Clinical Infection, Microbiology and Immunology, University of Liverpool, Ronald Ross Building, 8 West Derby Street, Liverpool, L69 7BE, UK
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Kolodkin-Gal I, Cohen-Cymberknoh M, Zamir G, Tsesis I, Rosen E. Targeting Persistent Biofilm Infections: Reconsidering the Topography of the Infection Site during Model Selection. Microorganisms 2022; 10:microorganisms10061164. [PMID: 35744683 PMCID: PMC9231179 DOI: 10.3390/microorganisms10061164] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 06/01/2022] [Accepted: 06/02/2022] [Indexed: 12/17/2022] Open
Abstract
The physiology of an organism in the environment reflects its interactions with the diverse physical, chemical, and biological properties of the surface. These principles come into consideration during model selection to study biofilm–host interactions. Biofilms are communities formed by beneficial and pathogenic bacteria, where cells are held together by a structured extracellular matrix. When biofilms are associated with a host, chemical gradients and their origins become highly relevant. Conventional biofilm laboratory models such as multiwall biofilm models and agar plate models poorly mimic these gradients. In contrast, ex vivo models possess the partial capacity to mimic the conditions of tissue-associated biofilm and a biofilm associated with a mineralized surface enriched in inorganic components, such as the human dentin. This review will highlight the progress achieved using these settings for two models of persistent infections: the infection of the lung tissue by Pseudomonas aeruginosa and the infection of the root canal by Enterococcus faecalis. For both models, we conclude that the limitations of the conventional in vitro systems necessitate a complimentary experimentation with clinically relevant ex vivo models during therapeutics development.
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Affiliation(s)
- Ilana Kolodkin-Gal
- Department of Plant Pathology and Microbiology, The Hebrew University of Jerusalem, Rehovot 7610001, Israel
- Correspondence: (I.K.-G.); (I.T.); (E.R.)
| | - Malena Cohen-Cymberknoh
- Pediatric Pulmonary Unit and Cystic Fibrosis Center, Hadassah Medical Center and Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112001, Israel;
| | - Gideon Zamir
- Department of Experimental Surgery, Hadassah Hebrew University Medical School, Jerusalem 9112001, Israel;
| | - Igor Tsesis
- Department of Endodontics, Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
- Correspondence: (I.K.-G.); (I.T.); (E.R.)
| | - Eyal Rosen
- Department of Endodontics, Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
- Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv 6997801, Israel
- Correspondence: (I.K.-G.); (I.T.); (E.R.)
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Transcriptional Profiling of Pseudomonas aeruginosa Infections. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:303-323. [DOI: 10.1007/978-3-031-08491-1_11] [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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Pseudomonas aeruginosa in the Cystic Fibrosis Lung. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:347-369. [DOI: 10.1007/978-3-031-08491-1_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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