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Nokso-Koivisto J, Ehrlich GD, Enoksson F, Komatsu K, Mason K, Melhus Å, Patel JA, Vijayasekaran S, Ryan A. Otitis media: Interactions between host and environment, immune and inflammatory responses. Int J Pediatr Otorhinolaryngol 2024; 176:111798. [PMID: 38041988 DOI: 10.1016/j.ijporl.2023.111798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 11/12/2023] [Accepted: 11/19/2023] [Indexed: 12/04/2023]
Abstract
OBJECTIVE To review and highlight progress in otitis media (OM) research in the areas of immunology, inflammation, environmental influences and host-pathogen responses from 2019 to 2023. Opportunities for innovative future research were also identified. DATA SOURCES PubMed database of the National Library of Medicine. REVIEW METHODS Key topics were assigned to each panel member for detailed review. Search of the literature was from June 2019 until February 2023. Draft reviews were collated, circulated, and discussed among panel members at the 22nd International Symposium on Recent Advances in Otitis Media in June 2023. The final manuscript was prepared and approved by all the panel members. CONCLUSIONS Important advances were identified in: environmental influences that enhance OM susceptibility; polymicrobial middle ear (ME) infections; the role of adaptive immunity defects in otitis-proneness; additional genes linked to OM; leukocyte contributions to OM pathogenesis and recovery; and novel interventions in OM based on host responses to infection. Innovative areas of research included: identification of novel bacterial genes and pathways important for OM persistence, bacterial adaptations and evolution that enhance chronicity; animal and human ME gene expression, including at the single-cell level; and Sars-CoV-2 infection of the ME and Eustachian tube.
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Affiliation(s)
- Johanna Nokso-Koivisto
- Department of Otorhinolaryngology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
| | - Garth D Ehrlich
- Department of Microbiology and Immunology and Department of Otolaryngology - Head and Neck Surgery, Drexel University College of Medicine, Philadelphia, PA, USA
| | | | - Kensei Komatsu
- Center for Inflammation, Immunity & Infection, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA
| | - Kevin Mason
- The Research Institute at Nationwide Children's Hospital, Infectious Diseases Institute, The Ohio State University School of Medicine, Columbus, OH, USA
| | - Åsa Melhus
- Department of Medical Sciences, Section of Clinical Bacteriology, Uppsala University, Uppsala, Sweden
| | - Janak A Patel
- Department of Infection Control & Healthcare Epidemiology and Division of Pediatric Infectious Diseases, Department of Pediatrics, University of Texas Medical Branch, Galveston, TX, USA
| | - Shiyan Vijayasekaran
- Perth ENT Centre, Perth Children's Hospital, University of Western Australia, Perth, Australia
| | - Allen Ryan
- Department of Surgery, Division of Otolaryngology, University of California San Diego, San Diego, CA, USA
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Atto B, Anteneh Y, Bialasiewicz S, Binks MJ, Hashemi M, Hill J, Thornton RB, Westaway J, Marsh RL. The Respiratory Microbiome in Paediatric Chronic Wet Cough: What Is Known and Future Directions. J Clin Med 2023; 13:171. [PMID: 38202177 PMCID: PMC10779485 DOI: 10.3390/jcm13010171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 12/13/2023] [Accepted: 12/17/2023] [Indexed: 01/12/2024] Open
Abstract
Chronic wet cough for longer than 4 weeks is a hallmark of chronic suppurative lung diseases (CSLD), including protracted bacterial bronchitis (PBB), and bronchiectasis in children. Severe lower respiratory infection early in life is a major risk factor of PBB and paediatric bronchiectasis. In these conditions, failure to clear an underlying endobronchial infection is hypothesised to drive ongoing inflammation and progressive tissue damage that culminates in irreversible bronchiectasis. Historically, the microbiology of paediatric chronic wet cough has been defined by culture-based studies focused on the detection and eradication of specific bacterial pathogens. Various 'omics technologies now allow for a more nuanced investigation of respiratory pathobiology and are enabling development of endotype-based models of care. Recent years have seen substantial advances in defining respiratory endotypes among adults with CSLD; however, less is understood about diseases affecting children. In this review, we explore the current understanding of the airway microbiome among children with chronic wet cough related to the PBB-bronchiectasis diagnostic continuum. We explore concepts emerging from the gut-lung axis and multi-omic studies that are expected to influence PBB and bronchiectasis endotyping efforts. We also consider how our evolving understanding of the airway microbiome is translating to new approaches in chronic wet cough diagnostics and treatments.
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Affiliation(s)
- Brianna Atto
- School of Health Sciences, University of Tasmania, Launceston, TAS 7248, Australia;
| | - Yitayal Anteneh
- Child and Maternal Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT 0811, Australia; (Y.A.); (M.J.B.); (J.W.)
| | - Seweryn Bialasiewicz
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia;
| | - Michael J. Binks
- Child and Maternal Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT 0811, Australia; (Y.A.); (M.J.B.); (J.W.)
- SAHMRI Women and Kids, South Australian Health and Medical Research Institute, Adelaide, SA 5000, Australia
| | - Mostafa Hashemi
- Department of Chemical and Biological Engineering, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada; (M.H.); (J.H.)
| | - Jane Hill
- Department of Chemical and Biological Engineering, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada; (M.H.); (J.H.)
- Spire Health Technology, PBC, Seattle, WA 98195, USA
| | - Ruth B. Thornton
- Centre for Child Health Research, University of Western Australia, Perth, WA 6009, Australia;
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, Perth, WA 6009, Australia
| | - Jacob Westaway
- Child and Maternal Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT 0811, Australia; (Y.A.); (M.J.B.); (J.W.)
- Centre for Tropical Bioinformatics and Molecular Biology, James Cook University, Cairns, QLD 4811, Australia
| | - Robyn L. Marsh
- School of Health Sciences, University of Tasmania, Launceston, TAS 7248, Australia;
- Child and Maternal Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT 0811, Australia; (Y.A.); (M.J.B.); (J.W.)
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Tamir SO, Bialasiewicz S, Brennan-Jones CG, Der C, Kariv L, Macharia I, Marsh RL, Seguya A, Thornton R. ISOM 2023 research Panel 4 - Diagnostics and microbiology of otitis media. Int J Pediatr Otorhinolaryngol 2023; 174:111741. [PMID: 37788516 DOI: 10.1016/j.ijporl.2023.111741] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/17/2023] [Accepted: 09/19/2023] [Indexed: 10/05/2023]
Abstract
OBJECTIVES To identify and review key research advances from the literature published between 2019 and 2023 on the diagnosis and microbiology of otitis media (OM) including acute otitis media (AOM), recurrent AOM (rAOM), otitis media with effusion (OME), chronic suppurative otitis media (CSOM) and AOM complications (mastoiditis). DATA SOURCES PubMed database of the National Library of Medicine. REVIEW METHODS All relevant original articles published in Medline in English between July 2019 and February 2023 were identified. Studies that were reviews, case studies, relating to OM complications (other than mastoiditis), and studies focusing on guideline adherence, and consensus statements were excluded. Members of the panel drafted the report based on these search results. MAIN FINDINGS For the diagnosis section, 2294 unique records screened, 55 were eligible for inclusion. For the microbiology section 705 unique records were screened and 137 articles were eligible for inclusion. The main themes that arose in OM diagnosis were the need to incorporate multiple modalities including video-otoscopy, tympanometry, telemedicine and artificial intelligence for accurate diagnoses in all diagnostic settings. Further to this, was the use of new, cheap, readily available tools which may improve access in rural and lowmiddle income (LMIC) settings. For OM aetiology, PCR remains the most sensitive method for detecting middle ear pathogens with microbiome analysis still largely restricted to research use. The global pandemic response reduced rates of OM in children, but post-pandemic shifts should be monitored. IMPLICATION FOR PRACTICE AND FUTURE RESEARCH Cheap, easy to use multi-technique assessments combined with artificial intelligence and/or telemedicine should be integrated into future practice to improve diagnosis and treatment pathways in OM diagnosis. Longitudinal studies investigating the in-vivo process of OM development, timings and in-depth interactions between the triad of bacteria, viruses and the host immune response are still required. Standardized methods of collection and analysis for microbiome studies to enable inter-study comparisons are required. There is a need to target underlying biofilms if going to effectively prevent rAOM and OME and possibly enhance ventilation tube retention.
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Affiliation(s)
- Sharon Ovnat Tamir
- Department of Otolaryngology-Head and Neck Surgery, Sasmon Assuta Ashdod University Hospital, Faculty of Health Sciences, Ben Gurion University of the Negev, Israel.
| | - Seweryn Bialasiewicz
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Christopher G Brennan-Jones
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia; Faculty of Health Sciences, Curtin University, Perth, Western Australia, Australia
| | - Carolina Der
- Facultad de Medicina, Universidad Del Desarrollo, Dr Luis Calvo Mackenna Hospital, Santiago, Chile
| | - Liron Kariv
- Hearing, Speech and Language Institute, Sasmon Assuta Ashdod University Hospital, Israel
| | - Ian Macharia
- Kenyatta University Teaching, Referral & Research Hospital, Kenya
| | - Robyn L Marsh
- Menzies School of Health Research, Darwin, Australia; School of Health Sciences, University of Tasmania, Launceston, Australia
| | - Amina Seguya
- Department of Otolaryngology - Head and Neck Surgery, Mulago National Referral Hospital, Kampala, Uganda
| | - Ruth Thornton
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia; Centre for Child Health Research, University of Western Australia, Perth, Australia
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Chatziparasidis G, Kantar A, Grimwood K. Pathogenesis of nontypeable Haemophilus influenzae infections in chronic suppurative lung disease. Pediatr Pulmonol 2023. [PMID: 37133207 DOI: 10.1002/ppul.26446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 04/09/2023] [Accepted: 04/23/2023] [Indexed: 05/04/2023]
Abstract
The respiratory tract antimicrobial defense system is a multilayered defense mechanism that relies upon mucociliary clearance and components of both the innate and adaptive immune systems to protect the lungs from inhaled or aspirated microorganisms. One of these potential pathogens, nontypeable Haemophilus influenzae (NTHi), adopts several, multifaceted redundant strategies to successfully colonize the lower airways and establish a persistent infection. NTHi can impair mucociliary clearance, express multiple multifunctional adhesins for various cell types within the respiratory tract and evade host defenses by surviving within and between cells, forming biofilms, increasing antigenic drift, secreting proteases and antioxidants, and by host-pathogen cross-talk, impair macrophage and neutrophil function. NTHi is recognized as an important pathogen in several chronic lower respiratory disorders, such as protracted bacterial bronchitis, bronchiectasis, cystic fibrosis, and primary ciliary dyskinesia. The persistence of NTHi in human airways, including its capacity to form biofilms, results in chronic infection and inflammation, which can ultimately injure airway wall structures. The complex nature of the molecular pathogenetic mechanisms employed by NTHi is incompletely understood but improved understanding of its pathobiology will be important for developing effective therapies and vaccines, especially given the marked genetic heterogeneity of NTHi and its possession of phase-variable genes. Currently, no vaccine candidates are ready for large phase III clinical trials.
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Affiliation(s)
- Grigorios Chatziparasidis
- Paediatric Respiratory Unit, IASO Hospital, Larissa, Thessaly, Greece
- Faculty of Nursing, Thessaly University, Larissa, Greece
| | - Ahmad Kantar
- Pediatric Asthma and Cough Centre, Instituti Ospedalieri Bergamaschi, Bergamo, Italy
- Vita-Salute San Raffaele University, Milan, Italy
| | - Keith Grimwood
- School of Medicine and Dentistry, and Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia
- Departments of Infectious Disease and Paediatrics, Gold Coast Health, Southport, Queensland, Australia
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Hall-Stoodley L, McCoy KS. Biofilm aggregates and the host airway-microbial interface. Front Cell Infect Microbiol 2022; 12:969326. [PMID: 36081767 PMCID: PMC9445362 DOI: 10.3389/fcimb.2022.969326] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 07/28/2022] [Indexed: 11/13/2022] Open
Abstract
Biofilms are multicellular microbial aggregates that can be associated with host mucosal epithelia in the airway, gut, and genitourinary tract. The host environment plays a critical role in the establishment of these microbial communities in both health and disease. These host mucosal microenvironments however are distinct histologically, functionally, and regarding nutrient availability. This review discusses the specific mucosal epithelial microenvironments lining the airway, focusing on: i) biofilms in the human respiratory tract and the unique airway microenvironments that make it exquisitely suited to defend against infection, and ii) how airway pathophysiology and dysfunctional barrier/clearance mechanisms due to genetic mutations, damage, and inflammation contribute to biofilm infections. The host cellular responses to infection that contribute to resolution or exacerbation, and insights about evaluating and therapeutically targeting airway-associated biofilm infections are briefly discussed. Since so many studies have focused on Pseudomonas aeruginosa in the context of cystic fibrosis (CF) or on Haemophilus influenzae in the context of upper and lower respiratory diseases, these bacteria are used as examples. However, there are notable differences in diseased airway microenvironments and the unique pathophysiology specific to the bacterial pathogens themselves.
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Affiliation(s)
- Luanne Hall-Stoodley
- Department of Microbial Infection and Immunity, The Ohio State University College of Medicine, Columbus, OH, United States
- *Correspondence: Luanne Hall-Stoodley,
| | - Karen S. McCoy
- Division of Pulmonary Medicine, Nationwide Children’s Hospital, Columbus, OH, United States
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Buzzo JR, Devaraj A, Gloag ES, Jurcisek JA, Robledo-Avila F, Kesler T, Wilbanks K, Mashburn-Warren L, Balu S, Wickham J, Novotny LA, Stoodley P, Bakaletz LO, Goodman SD. Z-form extracellular DNA is a structural component of the bacterial biofilm matrix. Cell 2021; 184:5740-5758.e17. [PMID: 34735796 DOI: 10.1016/j.cell.2021.10.010] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 08/03/2021] [Accepted: 10/12/2021] [Indexed: 12/30/2022]
Abstract
Biofilms are community architectures adopted by bacteria inclusive of a self-formed extracellular matrix that protects resident bacteria from diverse environmental stresses and, in many species, incorporates extracellular DNA (eDNA) and DNABII proteins for structural integrity throughout biofilm development. Here, we present evidence that this eDNA-based architecture relies on the rare Z-form. Z-form DNA accumulates as biofilms mature and, through stabilization by the DNABII proteins, confers structural integrity to the biofilm matrix. Indeed, substances known to drive B-DNA into Z-DNA promoted biofilm formation whereas those that drive Z-DNA into B-DNA disrupted extant biofilms. Importantly, we demonstrated that the universal bacterial DNABII family of proteins stabilizes both bacterial- and host-eDNA in the Z-form in situ. A model is proposed that incorporates the role of Z-DNA in biofilm pathogenesis, innate immune response, and immune evasion.
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Affiliation(s)
- John R Buzzo
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Aishwarya Devaraj
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Erin S Gloag
- Department of Orthopedics, Ohio State University, Columbus, OH 43210, USA
| | - Joseph A Jurcisek
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Frank Robledo-Avila
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Theresa Kesler
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Kathryn Wilbanks
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Lauren Mashburn-Warren
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Sabarathnam Balu
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Joseph Wickham
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Laura A Novotny
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Paul Stoodley
- Department of Orthopedics, Ohio State University, Columbus, OH 43210, USA; Department of Microbial Infection and Immunity, Ohio State University, Columbus, OH 43210, USA; National Centre for Advanced Tribology at Southampton, University of Southampton, Southampton S017 1BJ, UK
| | - Lauren O Bakaletz
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA; Department of Pediatrics, College of Medicine, Ohio State University, Columbus, OH 43210, USA.
| | - Steven D Goodman
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA; Department of Pediatrics, College of Medicine, Ohio State University, Columbus, OH 43210, USA.
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Polymicrobial Interactions Operative during Pathogen Transmission. mBio 2021; 12:mBio.01027-21. [PMID: 34006664 PMCID: PMC8262881 DOI: 10.1128/mbio.01027-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Pathogen transmission is a key point not only for infection control and public health interventions but also for understanding the selective pressures in pathogen evolution. The “success” of a pathogen lies not in its ability to cause signs and symptoms of illness but in its ability to be shed from the initial hosts, survive between hosts, and then establish infection in a new host. Recent insights have shown the importance of the interaction between the pathogen and both the commensal microbiome and coinfecting pathogens on shedding, environmental survival, and acquisition of infection. Pathogens have evolved in the context of cooperation and competition with other microbes, and the roles of these cooperations and competitions in transmission can inform novel preventative and therapeutic strategies.
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Cacciatore I, Marinelli L. Patent evaluation of US2019338018 (A1) 2019-11-07 (antibody fragments for the treatment of biofilm-related disorders). Expert Opin Ther Pat 2020; 30:907-909. [PMID: 32970473 DOI: 10.1080/13543776.2020.1828864] [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: 10/23/2022]
Abstract
INTRODUCTION To date, microbial infections are also difficult to eradicate due to the increasing capability of bacteria to form a biofilm. In the era of antibiotic resistance, antibody-based approaches represent great promise in curing infective pathogens. The authors of US2019338018 patent propose a method for the treatment of biofilm-related disorders by using specific antibody fragments. AREAS COVERED The US2019338018 patent reports antibody fragments, pharmaceutical composition that contains it, and their application for the treatment of biofilm-linked disorders. Proof concept and preclinical results show that mAb mIhfB4NTHI Fab caused robust eradication of the biofilm in the middle ear lumen of chinchillas affected by Hemophilus influenzae infection. EXPERT OPINION Fab fragments of the US2019338018 patent are new in a general concept to treat bacterial biofilms and biofilm-linked disorders. However, pre-clinical data are only shown for the treatment with Fab fragments of infections caused by H. influenzae in the middle ear of chinchillas. There are no clinical trials that demonstrate that the treatment with Fab fragments may induce a disruption of biofilm produced by H. influenzae or other pathogens and an anti-inflammatory response in infected patients.
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Affiliation(s)
- Ivana Cacciatore
- Department of Pharmacy, University "G. d'Annunzio" of Chieti-Pescara , Chieti, Italy
| | - Lisa Marinelli
- Department of Pharmacy, University "G. d'Annunzio" of Chieti-Pescara , Chieti, Italy
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Nontypeable Haemophilus influenzae Type IV Pilus Mediates Augmented Adherence to Rhinovirus-Infected Human Airway Epithelial Cells. Infect Immun 2020; 88:IAI.00248-20. [PMID: 32540869 DOI: 10.1128/iai.00248-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 06/09/2020] [Indexed: 12/15/2022] Open
Abstract
Human rhinovirus (hRV) is frequently detected in the upper respiratory tract, and symptomatic infection is associated with an increased nasopharyngeal bacterial load, with subsequent development of secondary bacterial diseases. Nontypeable Haemophilus influenzae (NTHI) is a commensal bacterial species of the human nasopharynx; however, in the context of prior or concurrent upper respiratory tract viral infection, this bacterium commonly causes multiple diseases throughout the upper and lower respiratory tracts. The present study was conducted to determine the mechanism(s) by which hRV infection promotes the development of NTHI-induced diseases. We showed that hRV infection of polarized primary human airway epithelial cells resulted in increased adherence of NTHI, due in part to augmented expression of CEACAM1 and ICAM1, host cell receptors to which NTHI binds via engagement of multiple adhesins. Antibody blockade of these host cell receptors significantly reduced NTHI adherence. With a specific focus on the NTHI type IV pilus (T4P), which we have previously shown binds to ICAM1, an essential adhesin and virulence determinant, we next showed that T4P-directed antibody blockade significantly reduced NTHI adherence to hRV-infected airway cells and, further, that expression of this adhesin was required for the enhanced adherence observed. Collectively, these data provide a mechanism by which "the common cold" promotes diseases due to NTHI, and they add further support for the use of PilA (the majority subunit of T4P) as a vaccine antigen, since antibodies directed against PilA are expected to limit the notably increased bacterial load associated with hRV coinfection and thereby to prevent secondary NTHI-induced diseases of the respiratory tract.
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