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Tram G, Jen FEC, Phillips ZN, Lancashire JF, Timms J, Poole J, Jennings MP, Atack JM. Phasevarions in Haemophilus influenzae biogroup aegyptius control expression of multiple proteins. Microbiol Spectr 2024; 12:e0260123. [PMID: 38054719 PMCID: PMC10783040 DOI: 10.1128/spectrum.02601-23] [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: 06/21/2023] [Accepted: 10/31/2023] [Indexed: 12/07/2023] Open
Abstract
IMPORTANCE Haemophilus influenzae biogroup aegyptius is a human-adapted pathogen and the causative agent of Brazilian purpuric fever (BPF), an invasive disease with high mortality, that sporadically manifests in children previously suffering conjunctivitis. Phase variation is a rapid and reversible switching of gene expression found in many bacterial species, and typically associated with outer-membrane proteins. Phase variation of cytoplasmic DNA methyltransferases has been shown to play important roles in bacterial gene regulation and can act as epigenetic switches, regulating the expression of multiple genes as part of systems called phasevarions (phase-variable regulons). This study characterized two alleles of the ModA phasevarion present in H. influenzae biogroup aegyptius, ModA13, found in non-BPF causing strains and ModA16, unique to BPF causing isolates. Phase variation of ModA13 and ModA16 led to genome-wide changes to DNA methylation resulting in altered protein expression. These changes did not affect serum resistance in H. influenzae biogroup aegyptius strains.
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Affiliation(s)
- Greg Tram
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Freda E.-C. Jen
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Zachary N. Phillips
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - John F. Lancashire
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Jamie Timms
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Jessica Poole
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Michael P. Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - John M. Atack
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
- School of Environment and Science, Griffith University, Gold Coast, Queensland, Australia
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Monteith W, Pascoe B, Mourkas E, Clark J, Hakim M, Hitchings MD, McCarthy N, Yahara K, Asakura H, Sheppard SK. Contrasting genes conferring short- and long-term biofilm adaptation in Listeria. Microb Genom 2023; 9:001114. [PMID: 37850975 PMCID: PMC10634452 DOI: 10.1099/mgen.0.001114] [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: 06/22/2023] [Accepted: 09/28/2023] [Indexed: 10/19/2023] Open
Abstract
Listeria monocytogenes is an opportunistic food-borne bacterium that is capable of infecting humans with high rates of hospitalization and mortality. Natural populations are genotypically and phenotypically variable, with some lineages being responsible for most human infections. The success of L. monocytogenes is linked to its capacity to persist on food and in the environment. Biofilms are an important feature that allow these bacteria to persist and infect humans, so understanding the genetic basis of biofilm formation is key to understanding transmission. We sought to investigate the biofilm-forming ability of L. monocytogenes by identifying genetic variation that underlies biofilm formation in natural populations using genome-wide association studies (GWAS). Changes in gene expression of specific strains during biofilm formation were then investigated using RNA sequencing (RNA-seq). Genetic variation associated with enhanced biofilm formation was identified in 273 genes by GWAS and differential expression in 220 genes by RNA-seq. Statistical analyses show that the number of overlapping genes flagged by either type of experiment is less than expected by random sampling. This novel finding is consistent with an evolutionary scenario where rapid adaptation is driven by variation in gene expression of pioneer genes, and this is followed by slower adaptation driven by nucleotide changes within the core genome.
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Affiliation(s)
- William Monteith
- Department of Biology, University of Oxford, Oxford, UK
- Department of Biology, University of Bath, Claverton Down, Bath, UK
| | - Ben Pascoe
- Department of Biology, University of Oxford, Oxford, UK
- Big Data Institute, University of Oxford, Oxford, UK
| | | | - Jack Clark
- Department of Genetics, University of Leicester, University Road, Leicester, UK
| | - Maliha Hakim
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge, UK
| | - Matthew D. Hitchings
- Swasnsea University Medical School, Swansea University, Singleton Campus, Swansea, UK
| | - Noel McCarthy
- School of Medicine, Trinity College Dublin, Dublin, Ireland
| | - Koji Yahara
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Hiroshi Asakura
- Division of Biomedical Food Research, National Institute of Health Sciences, Tonomachi 3-25-26, Kawasaki-ku, Kawasaki, Kanagawa 210-9501, Japan
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Euba B, Gil-Campillo C, Asensio-López J, López-López N, Sen-Kilic E, Díez-Martínez R, Burgui S, Barbier M, Garmendia J. In Vivo Genome-Wide Gene Expression Profiling Reveals That Haemophilus influenzae Purine Synthesis Pathway Benefits Its Infectivity within the Airways. Microbiol Spectr 2023; 11:e0082323. [PMID: 37195232 PMCID: PMC10269889 DOI: 10.1128/spectrum.00823-23] [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: 02/23/2023] [Accepted: 04/27/2023] [Indexed: 05/18/2023] Open
Abstract
Haemophilus influenzae is a human-adapted bacterial pathogen that causes airway infections. Bacterial and host elements associated with the fitness of H. influenzae within the host lung are not well understood. Here, we exploited the strength of in vivo-omic analyses to study host-microbe interactions during infection. We used in vivo transcriptome sequencing (RNA-seq) for genome-wide profiling of both host and bacterial gene expression during mouse lung infection. Profiling of murine lung gene expression upon infection showed upregulation of lung inflammatory response and ribosomal organization genes, and downregulation of cell adhesion and cytoskeleton genes. Transcriptomic analysis of bacteria recovered from bronchoalveolar lavage fluid samples from infected mice showed a significant metabolic rewiring during infection, which was highly different from that obtained upon bacterial in vitro growth in an artificial sputum medium suitable for H. influenzae. In vivo RNA-seq revealed upregulation of bacterial de novo purine biosynthesis, genes involved in non-aromatic amino acid biosynthesis, and part of the natural competence machinery. In contrast, the expression of genes involved in fatty acid and cell wall synthesis and lipooligosaccharide decoration was downregulated. Correlations between upregulated gene expression and mutant attenuation in vivo were established, as observed upon purH gene inactivation leading to purine auxotrophy. Likewise, the purine analogs 6-thioguanine and 6-mercaptopurine reduced H. influenzae viability in a dose-dependent manner. These data expand our understanding of H. influenzae requirements during infection. In particular, H. influenzae exploits purine nucleotide synthesis as a fitness determinant, raising the possibility of purine synthesis as an anti-H. influenzae target. IMPORTANCE In vivo-omic strategies offer great opportunities for increased understanding of host-pathogen interplay and for identification of therapeutic targets. Here, using transcriptome sequencing, we profiled host and pathogen gene expression during H. influenzae infection within the murine airways. Lung pro-inflammatory gene expression reprogramming was observed. Moreover, we uncovered bacterial metabolic requirements during infection. In particular, we identified purine synthesis as a key player, highlighting that H. influenzae may face restrictions in purine nucleotide availability within the host airways. Therefore, blocking this biosynthetic process may have therapeutic potential, as supported by the observed inhibitory effect of 6-thioguanine and 6-mercaptopurine on H. influenzae growth. Together, we present key outcomes and challenges for implementing in vivo-omics in bacterial airway pathogenesis. Our findings provide metabolic insights into H. influenzae infection biology, raising the possibility of purine synthesis as an anti-H. influenzae target and of purine analog repurposing as an antimicrobial strategy against this pathogen.
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Affiliation(s)
- Begoña Euba
- Instituto de Agrobiotecnología (IDAB), Consejo Superior de Investigaciones Científicas (CSIC)-Gobierno de Navarra, Mutilva, Spain
| | - Celia Gil-Campillo
- Instituto de Agrobiotecnología (IDAB), Consejo Superior de Investigaciones Científicas (CSIC)-Gobierno de Navarra, Mutilva, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Javier Asensio-López
- Instituto de Agrobiotecnología (IDAB), Consejo Superior de Investigaciones Científicas (CSIC)-Gobierno de Navarra, Mutilva, Spain
- Asociación de la Industria Navarra (AIN)-Gobierno de Navarra, Cordovilla, Spain
| | - Nahikari López-López
- Instituto de Agrobiotecnología (IDAB), Consejo Superior de Investigaciones Científicas (CSIC)-Gobierno de Navarra, Mutilva, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Emel Sen-Kilic
- Vaccine Development Center, West Virginia University Health Sciences Center, Morgantown, West Virginia, USA
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | | | - Saioa Burgui
- Asociación de la Industria Navarra (AIN)-Gobierno de Navarra, Cordovilla, Spain
| | - Mariette Barbier
- Vaccine Development Center, West Virginia University Health Sciences Center, Morgantown, West Virginia, USA
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - Junkal Garmendia
- Instituto de Agrobiotecnología (IDAB), Consejo Superior de Investigaciones Científicas (CSIC)-Gobierno de Navarra, Mutilva, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
- Conexión Nanomedicina-CSIC, Madrid, Spain
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4
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Wang X, Yu D, Chen L. Antimicrobial resistance and mechanisms of epigenetic regulation. Front Cell Infect Microbiol 2023; 13:1199646. [PMID: 37389209 PMCID: PMC10306973 DOI: 10.3389/fcimb.2023.1199646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 05/26/2023] [Indexed: 07/01/2023] Open
Abstract
The rampant use of antibiotics in animal husbandry, farming and clinical disease treatment has led to a significant issue with pathogen resistance worldwide over the past decades. The classical mechanisms of resistance typically investigate antimicrobial resistance resulting from natural resistance, mutation, gene transfer and other processes. However, the emergence and development of bacterial resistance cannot be fully explained from a genetic and biochemical standpoint. Evolution necessitates phenotypic variation, selection, and inheritance. There are indications that epigenetic modifications also play a role in antimicrobial resistance. This review will specifically focus on the effects of DNA modification, histone modification, rRNA methylation and the regulation of non-coding RNAs expression on antimicrobial resistance. In particular, we highlight critical work that how DNA methyltransferases and non-coding RNAs act as transcriptional regulators that allow bacteria to rapidly adapt to environmental changes and control their gene expressions to resist antibiotic stress. Additionally, it will delve into how Nucleolar-associated proteins in bacteria perform histone functions akin to eukaryotes. Epigenetics, a non-classical regulatory mechanism of bacterial resistance, may offer new avenues for antibiotic target selection and the development of novel antibiotics.
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Affiliation(s)
- Xinrui Wang
- Medical Research Center, Fujian Maternity and Child Health Hospital, College of Clinical Medicine for Obstetrics and Gynecology and Pediatrics, Fujian Medical University, Fuzhou, Fujian, China
- National Health Commission Key Laboratory of Technical Evaluation of Fertility Regulation for Non-Human Primate, Fujian Maternity and Child Health Hospital, Fuzhou, Fujian, China
| | - Donghong Yu
- Medical Research Center, Fujian Maternity and Child Health Hospital, College of Clinical Medicine for Obstetrics and Gynecology and Pediatrics, Fujian Medical University, Fuzhou, Fujian, China
- National Health Commission Key Laboratory of Technical Evaluation of Fertility Regulation for Non-Human Primate, Fujian Maternity and Child Health Hospital, Fuzhou, Fujian, China
| | - Lu Chen
- Medical Research Center, Fujian Maternity and Child Health Hospital, College of Clinical Medicine for Obstetrics and Gynecology and Pediatrics, Fujian Medical University, Fuzhou, Fujian, China
- National Health Commission Key Laboratory of Technical Evaluation of Fertility Regulation for Non-Human Primate, Fujian Maternity and Child Health Hospital, Fuzhou, Fujian, China
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5
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Nahar N, Tram G, Jen FEC, Phillips ZN, Weinert L, Bossé J, Jabbari J, Gouil Q, Du MM, Ritchie M, Bowden R, Langford P, Tucker A, Jennings M, Turni C, Blackall P, Atack J. Actinobacillus pleuropneumoniae encodes multiple phase-variable DNA methyltransferases that control distinct phasevarions. Nucleic Acids Res 2023; 51:3240-3260. [PMID: 36840716 PMCID: PMC10123105 DOI: 10.1093/nar/gkad091] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/31/2023] [Accepted: 02/03/2023] [Indexed: 02/26/2023] Open
Abstract
Actinobacillus pleuropneumoniae is the cause of porcine pleuropneumonia, a severe respiratory tract infection that is responsible for major economic losses to the swine industry. Many host-adapted bacterial pathogens encode systems known as phasevarions (phase-variable regulons). Phasevarions result from variable expression of cytoplasmic DNA methyltransferases. Variable expression results in genome-wide methylation differences within a bacterial population, leading to altered expression of multiple genes via epigenetic mechanisms. Our examination of a diverse population of A. pleuropneumoniae strains determined that Type I and Type III DNA methyltransferases with the hallmarks of phase variation were present in this species. We demonstrate that phase variation is occurring in these methyltransferases, and show associations between particular Type III methyltransferase alleles and serovar. Using Pacific BioSciences Single-Molecule, Real-Time (SMRT) sequencing and Oxford Nanopore sequencing, we demonstrate the presence of the first ever characterised phase-variable, cytosine-specific Type III DNA methyltransferase. Phase variation of distinct Type III DNA methyltransferase in A. pleuropneumoniae results in the regulation of distinct phasevarions, and in multiple phenotypic differences relevant to pathobiology. Our characterisation of these newly described phasevarions in A. pleuropneumoniae will aid in the selection of stably expressed antigens, and direct and inform development of a rationally designed subunit vaccine against this major veterinary pathogen.
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Affiliation(s)
- Nusrat Nahar
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Greg Tram
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Freda E-C Jen
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Zachary N Phillips
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Lucy A Weinert
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Janine T Bossé
- Section of Paediatric Infectious Disease, Imperial College London, St Mary's Campus, London W2 1PG, UK
| | - Jafar S Jabbari
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Quentin Gouil
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Mei R M Du
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Matthew E Ritchie
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Rory Bowden
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Paul R Langford
- Section of Paediatric Infectious Disease, Imperial College London, St Mary's Campus, London W2 1PG, UK
| | - Alexander W Tucker
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Michael P Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Conny Turni
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Patrick J Blackall
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - John M Atack
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
- School of Environment and Science, Griffith University, Gold Coast, Queensland 4222, Australia
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6
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Garai P, Atack JM, Wills BM, Jennings MP, Bakaletz LO, Brockman KL. Adherence of Nontypeable Haemophilus influenzae to Cells and Substrates of the Airway Is Differentially Regulated by Individual ModA Phasevarions. Microbiol Spectr 2023; 11:e0409322. [PMID: 36511712 PMCID: PMC9927368 DOI: 10.1128/spectrum.04093-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 11/28/2022] [Indexed: 12/15/2022] Open
Abstract
Adherence of nontypeable Haemophilus influenzae (NTHi) to the host airway is an essential initial step for asymptomatic colonization of the nasopharynx, as well as development of disease. NTHi relies on strict regulation of multiple adhesins for adherence to host substrates encountered in the airway. NTHi encode a phase-variable cytoplasmic DNA methyltransferase, ModA, that regulates expression of multiple genes; a phasevarion (phase-variable regulon). Multiple modA alleles are present in NTHi, in which different alleles methylate a different DNA target, and each controls a different set of genes. However, the role of ModA phasevarions in regulating adherence of NTHi to the host airway is not well understood. This study therefore sought to investigate the role of four of the most prevalent ModA phasevarions in the regulation of adherence of NTHi to multiple substrates of the airway. Four clinical isolates of NTHi with unique modA alleles were tested in this study. The adherence of NTHi to mucus, middle ear epithelial cells, and vitronectin was regulated in a substrate-specific manner that was dependent on the ModA allele encoded. The adhesins Protein E and P4 were found to contribute to the ModA-regulated adherence of NTHi to distinct substrates. A better understanding of substrate-specific regulation of NTHi adherence by ModA phasevarions will allow identification of NTHi populations present at the site of disease within the airway and facilitate more directed development of vaccines and therapeutics. IMPORTANCE Nontypeable Haemophilus influenzae (NTHi) is a predominant pathogen of the human airway that causes respiratory infections such as otitis media (OM) and exacerbations in the lungs of patients suffering from chronic obstructive pulmonary disease (COPD). Due to the lack of a licensed vaccine against NTHi and the emergence of antibiotic-resistant strains, it is extremely challenging to target NTHi for treatment. NTHi adhesins are considered potential candidates for vaccines or other therapeutic approaches. The ModA phasevarions of NTHi play a role in the rapid adaptation of the pathogen to different environmental stress conditions. This study addressed the role of ModA phasevarions in the regulation of adherence of NTHi to specific host substrates found within the respiratory tract. The findings of this study improve our understanding of regulation of adherence of NTHi to the airway, which may further be used to enhance the potential of adhesins as vaccine antigens and therapeutic targets against NTHi.
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Affiliation(s)
- Preeti Garai
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - John M. Atack
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
- School of Environment and Science, Griffith University, Gold Coast, Queensland, Australia
| | - Brandon M. Wills
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Michael P. Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Lauren O. Bakaletz
- Abigail Wexner Research Institute, Center for Microbial Pathogenesis, Nationwide Children’s Hospital, Columbus, Ohio, USA
- College of Medicine, Department of Pediatrics, The Ohio State University, Columbus, Ohio, USA
| | - Kenneth L. Brockman
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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Janoušková M, Straw ML, Su YC, Riesbeck K. Gene Expression Regulation in Airway Pathogens: Importance for Otitis Media. Front Cell Infect Microbiol 2022; 12:826018. [PMID: 35252035 PMCID: PMC8895709 DOI: 10.3389/fcimb.2022.826018] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/19/2022] [Indexed: 11/13/2022] Open
Abstract
Otitis media (OM) is an inflammatory disorder in the middle ear. It is mainly caused by viruses or bacteria associated with the airways. Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis are the three main pathogens in infection-related OM, especially in younger children. In this review, we will focus upon the multifaceted gene regulation mechanisms that are well-orchestrated in S. pneumoniae, H. influenzae, and M. catarrhalis during the course of infection in the middle ear either in experimental OM or in clinical settings. The sophisticated findings from the past 10 years on how the othopathogens govern their virulence phenotypes for survival and host adaptation via phase variation- and quorum sensing-dependent gene regulation, will be systematically discussed. Comprehensive understanding of gene expression regulation mechanisms employed by pathogens during the onset of OM may provide new insights for the design of a new generation of antimicrobial agents in the fight against bacterial pathogens while combating the serious emergence of antimicrobial resistance.
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8
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Spatial persistence of Escherichia coli O157:H7 flowing on micropatterned structures inspired by stomata and microgrooves of leafy greens. INNOV FOOD SCI EMERG 2022. [DOI: 10.1016/j.ifset.2021.102889] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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9
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Weeks JR, Staples KJ, Spalluto CM, Watson A, Wilkinson TMA. The Role of Non-Typeable Haemophilus influenzae Biofilms in Chronic Obstructive Pulmonary Disease. Front Cell Infect Microbiol 2021; 11:720742. [PMID: 34422683 PMCID: PMC8373199 DOI: 10.3389/fcimb.2021.720742] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 07/15/2021] [Indexed: 11/13/2022] Open
Abstract
Non-typeable Haemophilus influenzae (NTHi) is an ubiquitous commensal-turned-pathogen that colonises the respiratory mucosa in airways diseases including Chronic Obstructive Pulmonary Disease (COPD). COPD is a progressive inflammatory syndrome of the lungs, encompassing chronic bronchitis that is characterised by mucus hypersecretion and impaired mucociliary clearance and creates a static, protective, humid, and nutrient-rich environment, with dysregulated mucosal immunity; a favourable environment for NTHi colonisation. Several recent large COPD cohort studies have reported NTHi as a significant and recurrent aetiological pathogen in acute exacerbations of COPD. NTHi proliferation has been associated with increased hospitalisation, disease severity, morbidity and significant lung microbiome shifts. However, some cohorts with patients at different severities of COPD do not report that NTHi is a significant aetiological pathogen in their COPD patients, indicating other obligate pathogens including Moraxella catarrhalis, Streptococcus pneumoniae and Pseudomonas aeruginosa as the cause. NTHi is an ubiquitous organism across healthy non-smokers, healthy smokers and COPD patients from childhood to adulthood, but it currently remains unclear why NTHi becomes pathogenic in only some cohorts of COPD patients, and what behaviours, interactions and adaptations are driving this susceptibility. There is emerging evidence that biofilm-phase NTHi may play a significant role in COPD. NTHi displays many hallmarks of the biofilm lifestyle and expresses key biofilm formation-promoting genes. These include the autoinducer-mediated quorum sensing system, epithelial- and mucus-binding adhesins and expression of a protective, self-produced polymeric substance matrix. These NTHi biofilms exhibit extreme tolerance to antimicrobial treatments and the immune system as well as expressing synergistic interspecific interactions with other lung pathogens including S. pneumoniae and M. catarrhalis. Whilst the majority of our understanding surrounding NTHi as a biofilm arises from otitis media or in-vitro bacterial monoculture models, the role of NTHi biofilms in the COPD lung is now being studied. This review explores the evidence for the existence of NTHi biofilms and their impact in the COPD lung. Understanding the nature of chronic and recurrent NTHi infections in acute exacerbations of COPD could have important implications for clinical treatment and identification of novel bactericidal targets.
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Affiliation(s)
- Jake R Weeks
- Clinical and Experimental Sciences, University of Southampton Faculty of Medicine, Southampton, United Kingdom
| | - Karl J Staples
- Clinical and Experimental Sciences, University of Southampton Faculty of Medicine, Southampton, United Kingdom.,National Institute for Health Research (NIHR) Southampton Biomedical Research Centre, Southampton General Hospital, Southampton, United Kingdom
| | - C Mirella Spalluto
- Clinical and Experimental Sciences, University of Southampton Faculty of Medicine, Southampton, United Kingdom.,National Institute for Health Research (NIHR) Southampton Biomedical Research Centre, Southampton General Hospital, Southampton, United Kingdom
| | - Alastair Watson
- Clinical and Experimental Sciences, University of Southampton Faculty of Medicine, Southampton, United Kingdom.,National Institute for Health Research (NIHR) Southampton Biomedical Research Centre, Southampton General Hospital, Southampton, United Kingdom.,Birmingham Medical School, University of Birmingham, Birmingham, United Kingdom
| | - Tom M A Wilkinson
- Clinical and Experimental Sciences, University of Southampton Faculty of Medicine, Southampton, United Kingdom.,National Institute for Health Research (NIHR) Southampton Biomedical Research Centre, Southampton General Hospital, Southampton, United Kingdom
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10
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Dhouib R, Nasreen M, Othman DSMP, Ellis D, Lee S, Essilfie AT, Hansbro PM, McEwan AG, Kappler U. The DmsABC Sulfoxide Reductase Supports Virulence in Non-typeable Haemophilus influenzae. Front Microbiol 2021; 12:686833. [PMID: 34367088 PMCID: PMC8340005 DOI: 10.3389/fmicb.2021.686833] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 06/21/2021] [Indexed: 11/15/2022] Open
Abstract
Although molybdenum-containing enzymes are well-established as having a key role in bacterial respiration, it is increasingly recognized that some may also support bacterial virulence. Here, we show that DmsABC, a putative dimethylsulfoxide (DMSO) reductase, is required for fitness of the respiratory pathogen Haemophilus influenzae (Hi) in different models of infection. Expression of the dmsABC operon increased with decreasing oxygen availability, but despite this, a Hi2019Δd msA strain did not show any defects in anaerobic growth on chemically defined medium (CDM), and viability was also unaffected. Although Hi2019Δd msA exhibited increased biofilm formation in vitro and greater resistance to hypochlorite killing compared to the isogenic wild-type strain, its survival in contact with primary human neutrophils, in infections of cultured tissue cells, or in a mouse model of lung infection was reduced compared to Hi2019WT. The tissue cell infection model revealed a two-fold decrease in intracellular survival, while in the mouse model of lung infection Hi2019Δd msA was strongly attenuated and below detection levels at 48 h post-inoculation. While Hi2019WT was recovered in approximately equal numbers from bronchoalveolar lavage fluid (BALF) and lung tissue, survival of Hi2019Δd msA was reduced in lung tissue compared to BALF samples, indicating that Hi2019Δd msA had reduced access to or survival in the intracellular niche. Our data clearly indicate for the first time a role for DmsABC in H. influenzae infection and that the conditions under which DmsABC is required in this bacterium are closely linked to interactions with the host.
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Affiliation(s)
- Rabeb Dhouib
- School of Chemistry and Molecular Biosciences, Australian Infectious Disease Research Centre, The University of Queensland, St Lucia, QLD, Australia
| | - Marufa Nasreen
- School of Chemistry and Molecular Biosciences, Australian Infectious Disease Research Centre, The University of Queensland, St Lucia, QLD, Australia
| | - Dk Seti Maimonah Pg Othman
- School of Chemistry and Molecular Biosciences, Australian Infectious Disease Research Centre, The University of Queensland, St Lucia, QLD, Australia
| | - Daniel Ellis
- School of Chemistry and Molecular Biosciences, Australian Infectious Disease Research Centre, The University of Queensland, St Lucia, QLD, Australia
| | - Simon Lee
- School of Chemistry and Molecular Biosciences, Australian Infectious Disease Research Centre, The University of Queensland, St Lucia, QLD, Australia
| | | | - Philip M. Hansbro
- Centre for Inflammation, Centenary Institute, School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia
| | - Alastair G. McEwan
- School of Chemistry and Molecular Biosciences, Australian Infectious Disease Research Centre, The University of Queensland, St Lucia, QLD, Australia
| | - Ulrike Kappler
- School of Chemistry and Molecular Biosciences, Australian Infectious Disease Research Centre, The University of Queensland, St Lucia, QLD, Australia
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11
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Phase Variation in HMW1A Controls a Phenotypic Switch in Haemophilus influenzae Associated with Pathoadaptation during Persistent Infection. mBio 2021; 12:e0078921. [PMID: 34154422 PMCID: PMC8262952 DOI: 10.1128/mbio.00789-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Genetic variants arising from within-patient evolution shed light on bacterial adaptation during chronic infection. Contingency loci generate high levels of genetic variation in bacterial genomes, enabling adaptation to the stringent selective pressures exerted by the host. A significant gap in our understanding of phase-variable contingency loci is the extent of their contribution to natural infections. The human-adapted pathogen nontypeable Haemophilus influenzae (NTHi) causes persistent infections, which contribute to underlying disease progression. The phase-variable high-molecular-weight (HMW) adhesins located on the NTHi surface mediate adherence to respiratory epithelial cells and, depending on the allelic variant, can also confer high epithelial invasiveness or hyperinvasion. In this study, we characterize the dynamics of HMW-mediated hyperinvasion in living cells and identify a specific HMW binding domain shared by hyperinvasive NTHi isolates of distinct pathological origins. Moreover, we observed that HMW expression decreased over time by using a longitudinal set of persistent NTHi strains collected from chronic obstructive pulmonary disease (COPD) patients, resulting from increased numbers of simple-sequence repeats (SSRs) downstream of the functional P2hmw1A promoter, which is the one primarily driving HMW expression. Notably, the increased SSR numbers at the hmw1 promoter region also control a phenotypic switch toward lower bacterial intracellular invasion and higher biofilm formation, likely conferring adaptive advantages during chronic airway infection by NTHi. Overall, we reveal novel molecular mechanisms of NTHi pathoadaptation based on within-patient lifestyle switching controlled by phase variation.
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12
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López-López N, Gil-Campillo C, Díez-Martínez R, Garmendia J. Learning from -omics strategies applied to uncover Haemophilus influenzae host-pathogen interactions: Current status and perspectives. Comput Struct Biotechnol J 2021; 19:3042-3050. [PMID: 34136102 PMCID: PMC8178019 DOI: 10.1016/j.csbj.2021.05.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 05/11/2021] [Accepted: 05/11/2021] [Indexed: 11/15/2022] Open
Abstract
Haemophilus influenzae has contributed to key bacterial genome sequencing hallmarks, as being not only the first bacterium to be genome-sequenced, but also starring the first genome-wide analysis of chromosomes directly transformed with DNA from a divergent genotype, and pioneering Tn-seq methodologies. Over the years, the phenomenal and constantly evolving development of -omic technologies applied to a whole range of biological questions of clinical relevance in the H. influenzae-host interplay, has greatly moved forward our understanding of this human-adapted pathogen, responsible for multiple acute and chronic infections of the respiratory tract. In this way, essential genes, virulence factors, pathoadaptive traits, and multi-layer gene expression regulatory networks with both genomic and epigenomic complexity levels are being elucidated. Likewise, the unstoppable increasing whole genome sequencing information underpinning H. influenzae great genomic plasticity, mainly when referring to non-capsulated strains, poses major challenges to understand the genomic basis of clinically relevant phenotypes and even more, to clearly highlight potential targets of clinical interest for diagnostic, therapeutic or vaccine development. We review here how genomic, transcriptomic, proteomic and metabolomic-based approaches are great contributors to our current understanding of the interactions between H. influenzae and the human airways, and point possible strategies to maximize their usefulness in the context of biomedical research and clinical needs on this human-adapted bacterial pathogen.
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Affiliation(s)
- Nahikari López-López
- Instituto de Agrobiotecnología, Consejo Superior de Investigaciones Científicas (IdAB-CSIC)-Gobierno de Navarra, Mutilva, Spain
| | - Celia Gil-Campillo
- Instituto de Agrobiotecnología, Consejo Superior de Investigaciones Científicas (IdAB-CSIC)-Gobierno de Navarra, Mutilva, Spain
| | | | - Junkal Garmendia
- Instituto de Agrobiotecnología, Consejo Superior de Investigaciones Científicas (IdAB-CSIC)-Gobierno de Navarra, Mutilva, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
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13
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Streptococcus suis Encodes Multiple Allelic Variants of a Phase-Variable Type III DNA Methyltransferase, ModS, That Control Distinct Phasevarions. mSphere 2021; 6:6/3/e00069-21. [PMID: 33980672 PMCID: PMC8125046 DOI: 10.1128/msphere.00069-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus suis is a causative agent of meningitis, polyarthritis, and polyserositis in swine, and it is a major cause of zoonotic meningitis in humans. Here, we investigate epigenetic gene regulation in S. suis by multiple phasevarions controlled by the phase-variable type III DNA methyltransferase ModS. Streptococcus suis is a significant cause of bacterial meningitis in humans, particularly in Southeast Asia, and is a leading cause of respiratory and invasive disease in pigs. Phase-variable DNA methyltransferases, associated with restriction-modification (R-M) systems, are a source of epigenetic gene regulation, controlling the expression of multiple genes. These systems are known as phasevarions (phase-variable regulons) and have been characterized in many host-adapted bacterial pathogens. We recently described the presence of a Type III DNA methyltransferase in S. suis, ModS, which contains a simple sequence repeat (SSR) tract within the open reading frame of the modS gene and which differed in length between individual strains. We also observed that multiple allelic variants of the modS gene were present in a population of S. suis isolates. Here, we demonstrate that a biphasic ON-OFF switching of expression occurs in the two most common ModS alleles, ModS1 and ModS2, and that switching is dependent on SSR tract length. Furthermore, we show using single-molecule real-time (SMRT) sequencing that ModS1 and ModS2 are active methyltransferases in S. suis. ON-OFF switching of each ModS allele results in the regulation of distinct phasevarions, with the ModS2 phasevarion impacting growth patterns and antibiotic resistance. This is the first demonstration of a phase-variable Type III DNA methyltransferase in a Gram-positive organism that controls a phasevarion. Characterizing the phenotypic effects of phasevarions in S. suis is key to understanding pathogenesis and the development of future vaccines. IMPORTANCEStreptococcus suis is a causative agent of meningitis, polyarthritis, and polyserositis in swine, and it is a major cause of zoonotic meningitis in humans. Here, we investigate epigenetic gene regulation in S. suis by multiple phasevarions controlled by the phase-variable Type III DNA methyltransferase ModS. This is the first characterized example of a Type III R-M system regulating a phasevarion in a Gram-positive organism. We demonstrate that biphasic ON-OFF switching of ModS expression results in differences in bacterial growth and antibiotic resistance. Understanding the effects of ModS phase variation is required to determine the stably expressed antigenic repertoire of S. suis, which will direct and inform the development of antimicrobial treatments and vaccines against this important pathogen.
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14
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Short B, Carson S, Devlin AC, Reihill JA, Crilly A, MacKay W, Ramage G, Williams C, Lundy FT, McGarvey LP, Thornbury KD, Martin SL. Non-typeable Haemophilus influenzae chronic colonization in chronic obstructive pulmonary disease (COPD). Crit Rev Microbiol 2021; 47:192-205. [PMID: 33455514 DOI: 10.1080/1040841x.2020.1863330] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Haemophilus influenzae is the most common cause of bacterial infection in the lungs of chronic obstructive pulmonary disease (COPD) patients and contributes to episodes of acute exacerbation which are associated with increased hospitalization and mortality. Due to the ability of H. influenzae to adhere to host epithelial cells, initial colonization of the lower airways can progress to a persistent infection and biofilm formation. This is characterized by changes in bacterial behaviour such as reduced cellular metabolism and the production of an obstructive extracellular matrix (ECM). Herein we discuss the multiple mechanisms by which H. influenzae contributes to the pathogenesis of COPD. In particular, mechanisms that facilitate bacterial adherence to host airway epithelial cells, biofilm formation, and microbial persistence through immune system evasion and antibiotic tolerance will be discussed.
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Affiliation(s)
- Bryn Short
- University of the West of Scotland, Paisley, United Kingdom
| | - Stephen Carson
- School of Pharmacy, Queen's University Belfast, Belfast, United Kingdom
| | - Anna-Claire Devlin
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
| | - James A Reihill
- School of Pharmacy, Queen's University Belfast, Belfast, United Kingdom
| | - Anne Crilly
- University of the West of Scotland, Paisley, United Kingdom
| | - William MacKay
- University of the West of Scotland, Paisley, United Kingdom
| | - Gordon Ramage
- Glasgow Biofilm Research Group, Oral Sciences, School of Medicine, Dentistry and Nursing, University of Glasgow, Glasgow, United Kingdom
| | - Craig Williams
- University of the West of Scotland, Paisley, United Kingdom
| | - Fionnuala T Lundy
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
| | - Lorcan P McGarvey
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
| | - Keith D Thornbury
- Smooth Muscle Research Group, Dundalk Institute of Technology, Dundalk, Ireland
| | - S Lorraine Martin
- School of Pharmacy, Queen's University Belfast, Belfast, United Kingdom
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15
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Genome-wide analysis of DNA uptake across the outer membrane of naturally competent Haemophilus influenzae. iScience 2020; 24:102007. [PMID: 33490915 PMCID: PMC7811141 DOI: 10.1016/j.isci.2020.102007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 11/30/2020] [Accepted: 12/23/2020] [Indexed: 01/15/2023] Open
Abstract
The genomes of naturally competent Pasteurellaceae and Neisseriaceae have many short uptake sequences (USS), which allow them to distinguish self-DNA from foreign DNA. To fully characterize this preference we developed genome-wide maps of DNA uptake using both a sequence-based computational model and genomic DNA that had been sequenced after uptake by and recovery from competent Haemophilus influenzae cells. When DNA fragments were shorter than the average USS spacing of ∼1,000 bp, sharp peaks of uptake were centered at USS and separated by valleys with 1000-fold lower uptake. Long DNA fragments (1.5–17 kb) gave much less variation, with 90% of positions having uptake within 2-fold of the mean. All detectable uptake biases arose from sequences that fit the USS uptake motif. Simulated competition predicted that, in its respiratory tract environment, H. influenzae will efficiently take up its own DNA even when human DNA is present in 100-fold excess. For short DNA fragments, an uptake sequence (USS) improves DNA uptake 1000-fold Most longer H. influenzae fragments have USS, giving even uptake across the genome Preferred USS are stiff, so strand melting may facilitate kinking for uptake H. influenzae will take up its own DNA 100-fold better than human DNA
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16
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Andersson DI, Balaban NQ, Baquero F, Courvalin P, Glaser P, Gophna U, Kishony R, Molin S, Tønjum T. Antibiotic resistance: turning evolutionary principles into clinical reality. FEMS Microbiol Rev 2020; 44:171-188. [PMID: 31981358 DOI: 10.1093/femsre/fuaa001] [Citation(s) in RCA: 119] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 01/24/2020] [Indexed: 02/06/2023] Open
Abstract
Antibiotic resistance is one of the major challenges facing modern medicine worldwide. The past few decades have witnessed rapid progress in our understanding of the multiple factors that affect the emergence and spread of antibiotic resistance at the population level and the level of the individual patient. However, the process of translating this progress into health policy and clinical practice has been slow. Here, we attempt to consolidate current knowledge about the evolution and ecology of antibiotic resistance into a roadmap for future research as well as clinical and environmental control of antibiotic resistance. At the population level, we examine emergence, transmission and dissemination of antibiotic resistance, and at the patient level, we examine adaptation involving bacterial physiology and host resilience. Finally, we describe new approaches and technologies for improving diagnosis and treatment and minimizing the spread of resistance.
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Affiliation(s)
- Dan I Andersson
- Department of Medical Biochemistry and Microbiology, University of Uppsala, BMC, Husargatan 3, 75237, Uppsala, Sweden
| | - Nathalie Q Balaban
- The Racah Institute of Physics, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, 9190401, Jerusalem, Israel
| | - Fernando Baquero
- Department of Microbiology, Ramón y Cajal Health Research Institute, Ctra. Colmenar Viejo Km 9,100 28034 - Madrid, Madrid, Spain
| | - Patrice Courvalin
- French National Reference Center for Antibiotics, Institut Pasteur, 25-28 Rue du Dr Roux, 75015 Paris, Paris, France
| | - Philippe Glaser
- Ecology and Evolution of Antibiotic Resistance, Institut Pasteur, 25-28 Rue du Dr Roux, 75015 Paris, Paris, France
| | - Uri Gophna
- School of Molecular Cell Biology and Biotechnology, Tel Aviv University, 121 Jack Green building, Tel-Aviv University, Ramat-Aviv, 6997801, Tel Aviv, Israel
| | - Roy Kishony
- Faculty of Biology, The Technion, Technion City, Haifa 3200003, Haifa, Israel
| | - Søren Molin
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet Building 220 2800 Kgs.Lyngby, Lyngby, Denmark
| | - Tone Tønjum
- Department of Microbiology, University of Oslo, OUS HF Rikshospitalet Postboks 4950 Nydalen 0424 Oslo, Oslo, Norway.,Oslo University Hospital, P. O. Box 4950 Nydalen N-0424 Oslo, Oslo, Norway
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17
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The Nontypeable Haemophilus influenzae Major Adhesin Hia Is a Dual-Function Lectin That Binds to Human-Specific Respiratory Tract Sialic Acid Glycan Receptors. mBio 2020; 11:mBio.02714-20. [PMID: 33144377 PMCID: PMC7642680 DOI: 10.1128/mbio.02714-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Host-adapted bacterial pathogens like NTHi have evolved specific mechanisms to colonize their restricted host niche. Relatively few of the adhesins expressed by NTHi have been characterized as regards their binding affinity at the molecular level. In this work, we show that the major NTHi adhesin Hia preferentially binds to Neu5Ac-α2-6-sialyllactosamine, the form of sialic acid expressed in humans. The receptors targeted by Hia in the human airway mirror those targeted by influenza A virus and indicates the broad importance of sialic acid glycans as receptors for microbes that colonize the human airway. NTHi is a human-adapted pathogen that colonizes the human respiratory tract. Strains of NTHi express multiple adhesins; however, there is a unique, mutually exclusive relationship between the major adhesins Hia and HMW1 and HMW2 (HMW1/2). Approximately 25% of NTHi strains express Hia, a phase-variable autotransporter protein that has a critical role in colonization of the host nasopharynx. The remaining 75% of strains express HMW1/2. Previous work has shown that the HMW1 and HMW2 proteins mediate binding to 2-3- and 2-6-linked sialic acid glycans found in the human respiratory tract. Here, we show that the high-affinity binding domain of Hia, binding domain 1 (BD1), is responsible for binding to α2-6-sialyllactosamine (2-6 SLN) glycans. BD1 is highly specific for glycans that incorporate the form of sialic acid expressed by humans, N-acetylneuraminic acid (Neu5Ac). We further show that Hia has lower-affinity binding activity for 2-3-linked sialic acid and that this binding activity is mediated via a distinct domain. Thus, Hia with its dual binding activities functionally mimics the combined activities of the HMW1 and HMW2 adhesins. In addition, we show that Hia has a role in biofilm formation by strains of NTHi that express the adhesin. Knowledge of the binding affinity of this major NTHi adhesin and putative vaccine candidate will direct and inform development of future vaccines and therapeutic strategies for this important pathogen.
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18
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Robledo-Avila FH, Ruiz-Rosado JDD, Partida-Sanchez S, Brockman KL. A Bacterial Epigenetic Switch in Non-typeable Haemophilus influenzae Modifies Host Immune Response During Otitis Media. Front Cell Infect Microbiol 2020; 10:512743. [PMID: 33194779 PMCID: PMC7644868 DOI: 10.3389/fcimb.2020.512743] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Accepted: 09/15/2020] [Indexed: 01/15/2023] Open
Abstract
Non-typeable Haemophilus influenzae (NTHi) causes multiple diseases of the human airway and is a predominant bacterial pathogen of acute otitis media and otitis media in which treatment fails. NTHi utilizes a system of phase variable epigenetic regulation, termed the phasevarion, to facilitate adaptation and survival within multiple sites of the human host. The NTHi phasevarion influences numerous disease-relevant phenotypes such as biofilm formation, antibiotic resistance, and opsonization. We have previously identified an advantageous selection for a specific phasevarion status, which significantly affects severity and chronicity of experimental otitis media. In this study, we utilized pure cultures of NTHi variants in which modA was either locked ON or locked OFF, and thus modA was unable to phase vary. These locked variants were used to assess the progression of experimental otitis media and define the specific immune response induced by each subpopulation. Although the initial disease caused by each subpopulation was similar, the immune response elicited by each subpopulation was unique. The modA2 OFF variant induced significantly greater activation of macrophages both in vitro and within the middle ear during disease. In contrast, the modA2 ON variant induced a greater neutrophil extracellular trap response, which led to greater killing of the modA2 ON variant. These data suggest that not only does the NTHi phasevarion facilitate adaptation, but also allows the bacteria to alter immune responses during disease. Understanding these complex bacterial-host interactions and the regulation of bacterial factors responsible is critical to the development of better diagnostic, treatment, and preventative strategies for these bacterial pathogens.
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Affiliation(s)
- Frank H Robledo-Avila
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, United States
| | - Juan de Dios Ruiz-Rosado
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, United States.,Department of Biochemistry and Immunology, National Technological Institute of Oaxaca, Oaxaca, Mexico
| | - Santiago Partida-Sanchez
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, United States.,Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Kenneth L Brockman
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, United States.,Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, United States.,Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, United States
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19
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Xu J, Gao Y, Meng Y, Wu W, Tsauo C, Guo T, Cao Y, Huang D, Zhou X, He J. Mechano-chemical coupling of irrigation enhances endodontic biofilm debridement. BIOFOULING 2020; 36:792-799. [PMID: 32873073 DOI: 10.1080/08927014.2020.1814753] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Jialei Xu
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yuan Gao
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yajun Meng
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- Department of VIP Dental Care, Stomatology Hospital of Xi’an Jiaotong University, Xi’an, China
| | - Weiwei Wu
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Chialing Tsauo
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Tingwei Guo
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - Yangpei Cao
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Dingming Huang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jinzhi He
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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20
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Thornton RB, Hakansson A, Hood DW, Nokso-Koivisto J, Preciado D, Riesbeck K, Richmond PC, Su YC, Swords WE, Brockman KL. Panel 7 - Pathogenesis of otitis media - a review of the literature between 2015 and 2019. Int J Pediatr Otorhinolaryngol 2020; 130 Suppl 1:109838. [PMID: 31879085 PMCID: PMC7062565 DOI: 10.1016/j.ijporl.2019.109838] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
OBJECTIVE To perform a comprehensive review of the literature from July 2015 to June 2019 on the pathogenesis of otitis media. Bacteria, viruses and the role of the microbiome as well as the host response are discussed. Directions for future research are also suggested. DATA SOURCES PubMed database of the National Library of Medicine. REVIEW METHODS PubMed was searched for any papers pertaining to OM pathogenesis between July 2015 and June 2019. If in English, abstracts were assessed individually for their relevance and included in the report. Members of the panel drafted the report based on these searches and on new data presented at the 20th International Symposium on Recent Advances in Otitis Media. CONCLUSIONS The main themes that arose in OM pathogenesis were around the need for symptomatic viral infections to develop disease. Different populations potentially having different mechanisms of pathogenesis. Novel bacterial otopathogens are emerging and need to be monitored. Animal models need to continue to be developed and used to understand disease pathogenesis. IMPLICATIONS FOR PRACTICE The findings in the pathogenesis panel have several implications for both research and clinical practice. The most urgent areas appear to be to continue monitoring the emergence of novel otopathogens, and the need to develop prevention and preventative therapies that do not rely on antibiotics and protect against the development of the initial OM episode.
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Affiliation(s)
- R B Thornton
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, Perth, Western Australia, Australia; School of Biomedical Sciences, Faculty Health and Medical Science, University of Western Australia, Perth, Western Australia, Australia
| | - A Hakansson
- Experimental Infection Medicine, Dept. of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - D W Hood
- MRC Harwell Institute, Mammalian Genetics Unit, Harwell Campus, Oxfordshire, OX11 0RD, UK
| | - J Nokso-Koivisto
- Department of Otorhinolaryngology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - D Preciado
- Sheikh Zayed Center for Pediatric Surgical Innovation, Children's National Health System, Washington, DC, USA; Division of Pediatric Otolaryngology, Children's National Health System, Washington, DC, USA
| | - K Riesbeck
- Clinical Microbiology, Dept. of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - P C Richmond
- School of Medicine, Division of Paediatrics, Faculty Health and Medical Science, University of Western Australia, Perth, Western Australia, Australia; Perth Children's Hospital, Perth, Western Australia, Australia
| | - Y C Su
- Clinical Microbiology, Dept. of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - W E Swords
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - K L Brockman
- Department of Microbiology & Immunology, Medical College of Wisconsin, Milwaukee, WI, USA.
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21
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Expression of the Nontypeable Haemophilus influenzae Type IV Pilus Is Stimulated by Coculture with Host Respiratory Tract Epithelial Cells. Infect Immun 2019; 87:IAI.00704-19. [PMID: 31548326 DOI: 10.1128/iai.00704-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 09/13/2019] [Indexed: 12/22/2022] Open
Abstract
The type IV pilus (Tfp) of nontypeable Haemophilus influenzae (NTHI) mediates adherence, colonization, motility, and biofilm formation, and the major protein subunit, PilA, is a promising vaccine candidate. Thus, it is crucial to understand how Tfp expression is regulated within the microenvironments of the human nasopharynx, which NTHI colonizes asymptomatically, and the more distal regions of the respiratory tract where NTHI-induced diseases occur. Here, we examined the effects of coculture of NTHI with human airway epithelial cells and heme availability on Tfp expression at temperatures typical of the human nasopharynx (34°C) or warmer anatomical sites during infection (37°C). Tfp expression was estimated by pilA promoter activity, pilA gene expression, and relative abundances of PilA and pilin protein. The results revealed that at both temperatures, NTHI cocultured with airway epithelial cells demonstrated significantly greater expression of pilA, PilA/pilin protein, and likely, fully assembled Tfp than NTHI cultured on an abiotic surface. Because NTHI is a heme auxotroph, we hypothesized that availability of heme from host cells might be a signal for Tfp expression. Thereby, we cultured NTHI in iron-limited medium, and we observed that supplementation with heme significantly increased pilA promoter activity. Collectively, our data suggested that NTHI Tfp expression was stimulated by soluble factor(s) released by epithelial cells, which are present in all microenvironments of the respiratory tract. The expression of this target antigen under conditions that mimic the human airway strongly supports the rationale for the use of PilA as a vaccine immunogen to prevent NTHI-induced diseases of the respiratory tract.
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22
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Parrish JM, Soni M, Mittal R. Subversion of host immune responses by otopathogens during otitis media. J Leukoc Biol 2019; 106:943-956. [PMID: 31075181 PMCID: PMC7166519 DOI: 10.1002/jlb.4ru0119-003r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 03/11/2019] [Accepted: 04/05/2019] [Indexed: 12/26/2022] Open
Abstract
Otitis media (OM) is one of the most common ear diseases affecting humans. Children are at greater risk and suffer most frequently from OM, which can cause serious deterioration in the quality of life. OM is generally classified into two main types: acute and chronic OM (AOM and COM). AOM is characterized by tympanic membrane swelling or otorrhea and is accompanied by signs or symptoms of ear infection. In COM, there is a tympanic membrane perforation and purulent discharge. The most common pathogens that cause AOM are Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis whereas Pseudomonas aeruginosa and Staphylococcus aureus are commonly associated with COM. Innate and adaptive immune responses provide protection against OM. However, pathogens employ a wide arsenal of weapons to evade potent immune responses and these mechanisms likely contribute to AOM and COM. Immunologic evasion is multifactorial, and involves damage to host mucociliary tract, genetic polymorphisms within otopathogens, the number and variety of different otopathogens in the nasopharynx as well as the interaction between the host's innate and adaptive immune responses. Otopathogens utilize host mucin production, phase variation, biofilm production, glycans, as well as neutrophil and eosinophilic extracellular traps to induce OM. The objective of this review article is to discuss our current understanding about the mechanisms through which otopathogens escape host immunity to induce OM. A better knowledge about the molecular mechanisms leading to subversion of host immune responses will provide novel clues to develop effective treatment modalities for OM.
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Affiliation(s)
- James M Parrish
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Manasi Soni
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Rahul Mittal
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida, USA
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Phillips ZN, Husna AU, Jennings MP, Seib KL, Atack JM. Phasevarions of bacterial pathogens - phase-variable epigenetic regulators evolving from restriction-modification systems. MICROBIOLOGY-SGM 2019; 165:917-928. [PMID: 30994440 DOI: 10.1099/mic.0.000805] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Phase-variable DNA methyltransferases control the expression of multiple genes via epigenetic mechanisms in a wide variety of bacterial species. These systems are called phasevarions, for phase-variable regulons. Phasevarions regulate genes involved in pathogenesis, host adaptation and antibiotic resistance. Many human-adapted bacterial pathogens contain phasevarions. These include leading causes of morbidity and mortality worldwide, such as non-typeable Haemophilus influenzae, Streptococcus pneumoniae and Neisseria spp. Phase-variable methyltransferases and phasevarions have also been discovered in environmental organisms and veterinary pathogens. The existence of many different examples suggests that phasevarions have evolved multiple times as a contingency strategy in the bacterial domain, controlling phenotypes that are important in adapting to environmental change. Many of the organisms that contain phasevarions have existing or emerging drug resistance. Vaccines may therefore represent the best and most cost-effective tool to prevent disease caused by these organisms. However, many phasevarions also control the expression of current and putative vaccine candidates; variable expression of antigens could lead to immune evasion, meaning that vaccines designed using these targets become ineffective. It is therefore essential to characterize phasevarions in order to determine an organism's stably expressed antigenic repertoire, and rationally design broadly effective vaccines.
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Affiliation(s)
- Zachary N Phillips
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Asma-Ul Husna
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Michael P Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Kate L Seib
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - John M Atack
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
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