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Aguilar D, Zhu F, Millet A, Millet N, Germano P, Pisegna J, Akbari O, Doherty TA, Swidergall M, Jendzjowsky N. Sensory neurons regulate stimulus-dependent humoral immunity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.04.574231. [PMID: 38260709 PMCID: PMC10802321 DOI: 10.1101/2024.01.04.574231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Sensory neurons sense pathogenic infiltration, serving to inform immune coordination of host defense. However, sensory neuron-immune interactions have been predominantly shown to drive innate immune responses. Humoral memory, whether protective or destructive, is acquired early in life - as demonstrated by both early exposure to streptococci and allergic disease onset. Our study further defines the role of sensory neuron influence on humoral immunity in the lung. Using a murine model of Streptococcus pneumonia pre-exposure and infection and a model of allergic asthma, we show that sensory neurons are required for B-cell and plasma cell recruitment and antibody production. In response to S. pneumoniae, sensory neuron depletion resulted in a larger bacterial burden, reduced B-cell populations, IgG release and neutrophil stimulation. Conversely, sensory neuron depletion reduced B-cell populations, IgE and asthmatic characteristics during allergen-induced airway inflammation. The sensory neuron neuropeptide released within each model differed. With bacterial infection, vasoactive intestinal polypeptide (VIP) was preferentially released, whereas substance P was released in response to asthma. Administration of VIP into sensory neuron-depleted mice suppressed bacterial burden and increased IgG levels, while VIP1R deficiency increased susceptibility to bacterial infection. Sensory neuron-depleted mice treated with substance P increased IgE and asthma, while substance P genetic ablation resulted in blunted IgE, similar to sensory neuron-depleted asthmatic mice. These data demonstrate that the immunogen differentially stimulates sensory neurons to release specific neuropeptides which specifically target B-cells. Targeting sensory neurons may provide an alternate treatment pathway for diseases involved with insufficient and/or aggravated humoral immunity.
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Urban BC, Gonçalves ANA, Loukov D, Passos FM, Reiné J, Gonzalez-Dias P, Solórzano C, Mitsi E, Nikolaou E, O'Connor D, Collins AM, Adler H, Pollard A, Rylance J, Gordon SB, Jochems SP, Nakaya HI, Ferreira DM. Inflammation of the nasal mucosa is associated with susceptibility to experimental pneumococcal challenge in older adults. Mucosal Immunol 2024:S1933-0219(24)00064-3. [PMID: 38950826 DOI: 10.1016/j.mucimm.2024.06.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 06/25/2024] [Accepted: 06/26/2024] [Indexed: 07/03/2024]
Abstract
Streptococcus pneumoniae colonization in the upper respiratory tract is linked to pneumococcal disease development, predominantly affecting young children and older adults. As the global population ages and comorbidities increase, there is a heightened concern about this infection. We investigated the immunological responses of older adults to pneumococcal-controlled human infection by analyzing the cellular composition and gene expression in the nasal mucosa. Our comparative analysis with data from a concurrent study in younger adults revealed distinct gene expression patterns in older individuals susceptible to colonization, highlighted by neutrophil activation and elevated levels of CXCL9 and CXCL10. Unlike younger adults challenged with pneumococcus, older adults did not show recruitment of monocytes into the nasal mucosa following nasal colonization. However, older adults who were protected from colonization showed increased degranulation of cluster of differentiation 8+ T cells, both before and after pneumococcal challenge. These findings suggest age-associated cellular changes, in particular enhanced mucosal inflammation, that may predispose older adults to pneumococcal colonization.
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Affiliation(s)
- Britta C Urban
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK; Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK; NIHR Oxford Biomedical Research Centre, Oxford, UK.
| | - André N A Gonçalves
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK; Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK; NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Dessi Loukov
- Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Fernando M Passos
- Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Jesús Reiné
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK; Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK; NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Patrícia Gonzalez-Dias
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK; Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK; NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Carla Solórzano
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK; Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK; NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Elena Mitsi
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK; Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK; NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Elissavet Nikolaou
- Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK; Infection, Immunity and Global Health, Murdoch Children's Research Institute, Parkville, Victoria, Australia; Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Parkville, Victoria, Australia
| | - Daniel O'Connor
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK; NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Andrea M Collins
- Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK; University Hospital Aintree, Liverpool University Hospitals Trust, Liverpool, UK
| | - Hugh Adler
- Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Andrew Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK; NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Jamie Rylance
- Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Stephen B Gordon
- Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK; Malawi-Liverpool-Wellcome Clinical Research Programme, Blantyre, Malawi
| | - Simon P Jochems
- Leiden University Centre for Infectious Diseases, Leiden University Medical Centre, Leiden, The Netherlands
| | - Helder I Nakaya
- Hospital Israelita Albert Einstein, São Paulo, Brazil; Department of Clinical and Toxicological Analysis, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Daniela M Ferreira
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK; Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK; NIHR Oxford Biomedical Research Centre, Oxford, UK.
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3
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Oladokun S, Sharif S. Exploring the complexities of poultry respiratory microbiota: colonization, composition, and impact on health. Anim Microbiome 2024; 6:25. [PMID: 38711114 DOI: 10.1186/s42523-024-00308-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 04/08/2024] [Indexed: 05/08/2024] Open
Abstract
An accurate understanding of the ecology and complexity of the poultry respiratory microbiota is of utmost importance for elucidating the roles of commensal or pathogenic microorganisms in the respiratory tract, as well as their associations with health or disease outcomes in poultry. This comprehensive review delves into the intricate aspects of the poultry respiratory microbiota, focusing on its colonization patterns, composition, and impact on poultry health. Firstly, an updated overview of the current knowledge concerning the composition of the microbiota in the respiratory tract of poultry is provided, as well as the factors that influence the dynamics of community structure and diversity. Additionally, the significant role that the poultry respiratory microbiota plays in economically relevant respiratory pathobiologies that affect poultry is explored. In addition, the challenges encountered when studying the poultry respiratory microbiota are addressed, including the dynamic nature of microbial communities, site-specific variations, the need for standardized protocols, the appropriate sequencing technologies, and the limitations associated with sampling methodology. Furthermore, emerging evidence that suggests bidirectional communication between the gut and respiratory microbiota in poultry is described, where disturbances in one microbiota can impact the other. Understanding this intricate cross talk holds the potential to provide valuable insights for enhancing poultry health and disease control. It becomes evident that gaining a comprehensive understanding of the multifaceted roles of the poultry respiratory microbiota, as presented in this review, is crucial for optimizing poultry health management and improving overall outcomes in poultry production.
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Affiliation(s)
- Samson Oladokun
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Shayan Sharif
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON, N1G 2W1, Canada.
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4
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Klimkaite L, Liveikis T, Kaspute G, Armalyte J, Aldonyte R. Air pollution-associated shifts in the human airway microbiome and exposure-associated molecular events. Future Microbiol 2023; 18:607-623. [PMID: 37477532 DOI: 10.2217/fmb-2022-0258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/22/2023] Open
Abstract
Publications addressing air pollution-induced human respiratory microbiome shifts are reviewed in this article. The healthy respiratory microbiota is characterized by a low density of bacteria, fungi and viruses with high diversity, and usually consists of Bacteroidetes, Firmicutes, Proteobacteria, Actinobacteria, Fusobacteria, viruses and fungi. The air's microbiome is highly dependent on air pollution levels and is directly reflected within the human respiratory microbiome. In addition, pollutants indirectly modify the local environment in human respiratory organs by reducing antioxidant capacity, misbalancing proteolysis and modulating inflammation, all of which regulate local microbiomes. Improving air quality leads to more diverse and healthy microbiomes of the local air and, subsequently, residents' airways.
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Affiliation(s)
| | | | - Greta Kaspute
- State Research Institute Center for Innovative Medicine, Vilnius, Lithuania
| | | | - Ruta Aldonyte
- State Research Institute Center for Innovative Medicine, Vilnius, Lithuania
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5
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McMahan RH, Hulsebus HJ, Najarro KM, Giesy LE, Frank DN, Orlicky DJ, Kovacs EJ. Age-Related Intestinal Dysbiosis and Enrichment of Gut-specific Bacteria in the Lung Are Associated With Increased Susceptibility to Streptococcus pneumoniae Infection in Mice. FRONTIERS IN AGING 2022; 3:859991. [PMID: 35392033 PMCID: PMC8986162 DOI: 10.3389/fragi.2022.859991] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 02/18/2022] [Indexed: 01/09/2023]
Abstract
The portion of the global population that is over the age of 65 is growing rapidly and this presents a number of clinical complications, as the aged population is at higher risk for various diseases, including infection. For example, advanced age is a risk factor for heightened morbidity and mortality following infection with Streptococcus pneumoniae. This increased vulnerability is due, at least in part, to age-related dysregulation of the immune response, a phenomenon termed immunosenescence. However, our understanding of the mechanisms influencing the immunosenescent state and its effects on the innate immune response to pneumonia remain incomplete. Recently, a role for the gut microbiome in age-specific alterations in immunity has been described. Here, we utilized a murine model of intranasal Streptococcus pneumoniae infection to investigate the effects of age on both the innate immune response and the intestinal microbial populations after infection. In aged mice, compared to their younger counterparts, infection with Streptococcus pneumoniae led to increased mortality, impaired lung function and inadequate bacterial control. This poor response to infection was associated with increased influx of neutrophils into the lungs of aged mice 24 h after infection. The exacerbated pulmonary immune response was not associated with increased pro-inflammatory cytokines in the lung compared to young mice but instead heightened expression of immune cell recruiting chemokines by lung neutrophils. Bacterial 16S-rRNA gene sequencing of the fecal microbiome of aged and young-infected mice revealed expansion of Enterobacteriaceae in the feces of aged, but not young mice, after infection. We also saw elevated levels of gut-derived bacteria in the lung of aged-infected mice, including the potentially pathogenic symbiote Escherichia coli. Taken together, these results reveal that, when compared to young mice, Streptococcus pneumoniae infection in age leads to increased lung neutrophilia along with potentially pathogenic alterations in commensal bacteria and highlight potential mechanistic targets contributing to the increased morbidity and mortality observed in infections in age.
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Affiliation(s)
- Rachel H. McMahan
- Department of Surgery, Division of GI, Trauma and Endocrine Surgery, and Alcohol Research Program, Burn Research Program, University of Colorado Denver, Aurora, CO, United States
- GI and Liver Innate Immune Program, University of Colorado Denver, Aurora, CO, United States
| | - Holly J. Hulsebus
- Department of Surgery, Division of GI, Trauma and Endocrine Surgery, and Alcohol Research Program, Burn Research Program, University of Colorado Denver, Aurora, CO, United States
- Immunology Graduate Program, University of Colorado Denver, Aurora, CO, United States
| | - Kevin M. Najarro
- Department of Surgery, Division of GI, Trauma and Endocrine Surgery, and Alcohol Research Program, Burn Research Program, University of Colorado Denver, Aurora, CO, United States
| | - Lauren E. Giesy
- Department of Surgery, Division of GI, Trauma and Endocrine Surgery, and Alcohol Research Program, Burn Research Program, University of Colorado Denver, Aurora, CO, United States
| | - Daniel N. Frank
- GI and Liver Innate Immune Program, University of Colorado Denver, Aurora, CO, United States
- Department of Medicine, Division of Infectious Diseases, University of Colorado Denver, Aurora, CO, United States
| | - David J. Orlicky
- GI and Liver Innate Immune Program, University of Colorado Denver, Aurora, CO, United States
- Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Elizabeth J. Kovacs
- Department of Surgery, Division of GI, Trauma and Endocrine Surgery, and Alcohol Research Program, Burn Research Program, University of Colorado Denver, Aurora, CO, United States
- GI and Liver Innate Immune Program, University of Colorado Denver, Aurora, CO, United States
- Immunology Graduate Program, University of Colorado Denver, Aurora, CO, United States
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6
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Abstract
Innate and adaptive immune responses decline with age, leading to greater susceptibility to infectious diseases and reduced responses to vaccines. Diseases are more severe in old than in young individuals and have a greater impact on health outcomes such as morbidity, disability, and mortality. Aging is characterized by increased low-grade chronic inflammation, so-called inflammaging, that represents a link between changes in immune cells and a number of diseases and syndromes typical of old age. In this review we summarize current knowledge on age-associated changes in immune cells with special emphasis on B cells, which are more inflammatory and less responsive to infections and vaccines in the elderly. We highlight recent findings on factors and pathways contributing to inflammaging and how these lead to dysfunctional immune responses. We summarize recent published studies showing that adipose tissue, which increases in size with aging, contributes to inflammaging and dysregulated B cell function.
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Affiliation(s)
- Daniela Frasca
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida 33136, USA; .,Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida 33136, USA.,Miami Integrative Metabolomics Research Center, University of Miami Miller School of Medicine, Miami, Florida 33136, USA
| | - Alain Diaz
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida 33136, USA;
| | - Maria Romero
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida 33136, USA;
| | - Denisse Garcia
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida 33136, USA;
| | - Bonnie B Blomberg
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida 33136, USA; .,Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida 33136, USA
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7
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Slimmen LJM, Janssens HM, van Rossum AMC, Unger WWJ. Antigen-Presenting Cells in the Airways: Moderating Asymptomatic Bacterial Carriage. Pathogens 2021; 10:pathogens10080945. [PMID: 34451409 PMCID: PMC8400527 DOI: 10.3390/pathogens10080945] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/16/2021] [Accepted: 07/22/2021] [Indexed: 12/18/2022] Open
Abstract
Bacterial respiratory tract infections (RTIs) are a major global health burden, and the role of antigen-presenting cells (APCs) in mounting an immune response to contain and clear invading pathogens is well-described. However, most encounters between a host and a bacterial pathogen do not result in symptomatic infection, but in asymptomatic carriage instead. The fact that a pathogen will cause infection in one individual, but not in another does not appear to be directly related to bacterial density, but rather depend on qualitative differences in the host response. Understanding the interactions between respiratory pathogens and airway APCs that result in asymptomatic carriage, will provide better insight into the factors that can skew this interaction towards infection. This review will discuss the currently available knowledge on airway APCs in the context of asymptomatic bacterial carriage along the entire respiratory tract. Furthermore, in order to interpret past and futures studies into this topic, we propose a standardized nomenclature of the different stages of carriage and infection, based on the pathogen’s position with regard to the epithelium and the amount of inflammation present.
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Affiliation(s)
- Lisa J. M. Slimmen
- Laboratory of Pediatrics, Department of Pediatrics, Erasmus MC-Sophia Children’s Hospital, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands;
- Division of Respiratory Medicine and Allergology, Department of Pediatrics, Erasmus MC-Sophia Children’s Hospital, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands;
| | - Hettie M. Janssens
- Division of Respiratory Medicine and Allergology, Department of Pediatrics, Erasmus MC-Sophia Children’s Hospital, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands;
| | - Annemarie M. C. van Rossum
- Division of Infectious Diseases and Immunology, Department of Pediatrics, Erasmus MC-Sophia Children’s Hospital, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands;
| | - Wendy W. J. Unger
- Laboratory of Pediatrics, Department of Pediatrics, Erasmus MC-Sophia Children’s Hospital, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands;
- Correspondence:
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Dayie NTKD, Sekoh DNK, Kotey FCN, Egyir B, Tetteh-Quarcoo PB, Adutwum-Ofosu KK, Ahenkorah J, Osei MM, Donkor ES. Nasopharyngeal Carriage of Methicillin-Resistant Staphylococcus aureus (MRSA) among Sickle Cell Disease (SCD) Children in the Pneumococcal Conjugate Vaccine Era. Infect Dis Rep 2021; 13:191-204. [PMID: 33804397 PMCID: PMC7931118 DOI: 10.3390/idr13010022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 02/11/2021] [Accepted: 02/23/2021] [Indexed: 12/17/2022] Open
Abstract
The aim of this cross-sectional study was to investigate Staphylococcus aureus nasopharyngeal carriage epidemiology in relation to other nasopharyngeal bacterial colonizers among sickle cell disease (SCD) children about five years into pneumococcal conjugate vaccine 13 (PCV-13) introduction in Ghana. The study involved bacteriological culture of nasopharyngeal swabs obtained from 202 SCD children recruited from the Princess Marie Louise Children's Hospital. S. aureus isolates were identified using standard methods and subjected to antimicrobial susceptibility testing using the Kirby-Bauer disc diffusion method. Cefoxitin-resistant S. aureus isolates were screened for carriage of the mecA, pvl, and tsst-1 genes using multiplex polymerase chain reaction. The carriage prevalence of S. aureus was 57.9% (n = 117), and that of methicillin-resistant S. aureus (MRSA) was 3.5% (n = 7). Carriage of the mecA, pvl, and tsst-1 genes were respectively demonstrated in 20.0% (n = 7), 85.7% (n = 30), and 11.4% (n = 4) of the cefoxitin-resistant S. aureus isolates. PCV-13 vaccination (OR = 0.356, p = 0.004) and colonization with coagulase-negative staphylococci (CoNS) (OR = 0.044, p < 0.0001) each protected against S. aureus carriage. However, none of these and other features of the participants emerged as a determinant of MRSA carriage. The following antimicrobial resistance rates were observed in MRSA compared to methicillin-sensitive S. aureus: clindamycin (28.6% vs. 4.3%), erythromycin (42.9% vs. 19.1%), tetracycline (100% vs. 42.6%), teicoplanin (14.3% vs. 2.6%), penicillin (100% vs. 99.1%), amoxiclav (28.6% vs. 3.5%), linezolid (14.3% vs. 0.0%), ciprofloxacin (42.9% vs. 13.9%), and gentamicin (42.9% vs. 13.0%). The proportion of S. aureus isolates that were multidrug resistant was 37.7% (n = 46). We conclude that S. aureus was the predominant colonizer of the nasopharynx of the SCD children, warranting the continuous monitoring of this risk group for invasive S. aureus infections.
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Affiliation(s)
- Nicholas T. K. D. Dayie
- Department of Medical Microbiology, University of Ghana Medical School, P.O. Box KB 4236, Korle Bu, Accra 00233, Ghana; (D.N.K.S.); (F.C.N.K.); (P.B.T.-Q.); (M.-M.O.); (E.S.D.)
| | - Deborah N. K. Sekoh
- Department of Medical Microbiology, University of Ghana Medical School, P.O. Box KB 4236, Korle Bu, Accra 00233, Ghana; (D.N.K.S.); (F.C.N.K.); (P.B.T.-Q.); (M.-M.O.); (E.S.D.)
- FleRhoLife Research Consult, P.O. Box TS 853, Teshie, Accra 00233, Ghana
| | - Fleischer C. N. Kotey
- Department of Medical Microbiology, University of Ghana Medical School, P.O. Box KB 4236, Korle Bu, Accra 00233, Ghana; (D.N.K.S.); (F.C.N.K.); (P.B.T.-Q.); (M.-M.O.); (E.S.D.)
- FleRhoLife Research Consult, P.O. Box TS 853, Teshie, Accra 00233, Ghana
| | - Beverly Egyir
- Department of Bacteriology, Noguchi Memorial Institute for Medical Research, University of Ghana, P.O. Box LG 581, Legon, Accra 00233, Ghana;
| | - Patience B. Tetteh-Quarcoo
- Department of Medical Microbiology, University of Ghana Medical School, P.O. Box KB 4236, Korle Bu, Accra 00233, Ghana; (D.N.K.S.); (F.C.N.K.); (P.B.T.-Q.); (M.-M.O.); (E.S.D.)
| | - Kevin Kofi Adutwum-Ofosu
- Department of Anatomy, University of Ghana Medical School, P.O. Box KB 4236, Korle Bu, Accra 00233, Ghana; (K.K.A.-O.); (J.A.)
| | - John Ahenkorah
- Department of Anatomy, University of Ghana Medical School, P.O. Box KB 4236, Korle Bu, Accra 00233, Ghana; (K.K.A.-O.); (J.A.)
| | - Mary-Magdalene Osei
- Department of Medical Microbiology, University of Ghana Medical School, P.O. Box KB 4236, Korle Bu, Accra 00233, Ghana; (D.N.K.S.); (F.C.N.K.); (P.B.T.-Q.); (M.-M.O.); (E.S.D.)
- FleRhoLife Research Consult, P.O. Box TS 853, Teshie, Accra 00233, Ghana
| | - Eric S. Donkor
- Department of Medical Microbiology, University of Ghana Medical School, P.O. Box KB 4236, Korle Bu, Accra 00233, Ghana; (D.N.K.S.); (F.C.N.K.); (P.B.T.-Q.); (M.-M.O.); (E.S.D.)
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Saint-Criq V, Lugo-Villarino G, Thomas M. Dysbiosis, malnutrition and enhanced gut-lung axis contribute to age-related respiratory diseases. Ageing Res Rev 2021; 66:101235. [PMID: 33321253 DOI: 10.1016/j.arr.2020.101235] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/23/2020] [Accepted: 12/09/2020] [Indexed: 12/12/2022]
Abstract
Older people are at an increased risk of developing respiratory diseases such as chronic obstructive pulmonary diseases, asthma, idiopathic pulmonary fibrosis or lung infections. Susceptibility to these diseases is partly due to the intrinsic ageing process, characterized by genomic, cellular and metabolic hallmarks and immunosenescence, and is associated with changes in the intestinal microbiota. Importantly, in the lungs, ageing is also associated with a dysbiosis and loss of resilience of the resident microbiota and alterations of the gut-lung axis. Notably, as malnutrition is often observed in the elderly, nutrition is one of the most accessible modifiable factors affecting both senescence and microbiota. This article reviews the changes affecting the lung and its resident microbiota during ageing, as well as the interconnections between malnutrition, senescence, microbiota, gut-lung axis and respiratory health. As the communication along the gut-lung axis becomes more permissive with ageing, this review also explores the evidence that the gut and lung microbiota are key players in the maintenance of healthy lungs, and as such, are potential targets for nutrition-based preventive strategies against lung disease in elderly populations.
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10
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Understanding Human Microbiota Offers Novel and Promising Therapeutic Options against Candida Infections. Pathogens 2021; 10:pathogens10020183. [PMID: 33572162 PMCID: PMC7915436 DOI: 10.3390/pathogens10020183] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 01/20/2021] [Accepted: 02/02/2021] [Indexed: 12/12/2022] Open
Abstract
Human fungal pathogens particularly of Candida species are one of the major causes of hospital acquired infections in immunocompromised patients. The limited arsenal of antifungal drugs to treat Candida infections with concomitant evolution of multidrug resistant strains further complicates the management of these infections. Therefore, deployment of novel strategies to surmount the Candida infections requires immediate attention. The human body is a dynamic ecosystem having microbiota usually involving symbionts that benefit from the host, but in turn may act as commensal organisms or affect positively (mutualism) or negatively (pathogenic) the physiology and nourishment of the host. The composition of human microbiota has garnered a lot of recent attention, and despite the common occurrence of Candida spp. within the microbiota, there is still an incomplete picture of relationships between Candida spp. and other microorganism, as well as how such associations are governed. These relationships could be important to have a more holistic understanding of the human microbiota and its connection to Candida infections. Understanding the mechanisms behind commensalism and pathogenesis is vital for the development of efficient therapeutic strategies for these Candida infections. The concept of host-microbiota crosstalk plays critical roles in human health and microbiota dysbiosis and is responsible for various pathologies. Through this review, we attempted to analyze the types of human microbiota and provide an update on the current understanding in the context of health and Candida infections. The information in this article will help as a resource for development of targeted microbial therapies such as pre-/pro-biotics and microbiota transplant that has gained advantage in recent times over antibiotics and established as novel therapeutic strategy.
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11
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Zhou Y, Zhang M, Liu Q, Feng J. The alterations of tracheal microbiota and inflammation caused by different levels of ammonia exposure in broiler chickens. Poult Sci 2021; 100:685-696. [PMID: 33518122 PMCID: PMC7858136 DOI: 10.1016/j.psj.2020.11.026] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/03/2020] [Accepted: 11/09/2020] [Indexed: 12/11/2022] Open
Abstract
Ammonia (NH3) is a known harmful gas and exists in haze, forming secondary organic aerosols. Exposure to ambient ammonia correlates with the respiratory tract infection, and microbiota in the upper respiratory tract is an emerging crucial player in the homeostatic regulation of respiratory tract infection, and microbiota perturbation is usually accompanied by the inflammatory reactions; however, the effects of different levels of ammonia exposure on tracheal microbiota and inflammation are unclear. A total of 288 22-day-old male Arbor Acres broilers were chosen and divided into 4 groups with 6 replicates of 12 chickens, and respectively exposed to ammonia at 0, 15, 25, and 35 ppm for 21-d trial period. Cytokines (interleukin (IL)-1β, IL-6, and IL-10) in the trachea were measured at the 21 d of exposure to NH3. Tracheal microbiota at the 21 d was analyzed by the 16S rRNA gene analysis. The results showed that an increase in ammonia levels, even in 15 ppm, significantly decreased the alpha diversity and changed the bacterial community structure. Six genera (Faecalibacterium, Ruminococcus]_torques_group, unclassified_f__Lachnospiraceae, Ruminococcaceae_UCG-014, Streptococcus, Blautia) significantly increased, whereas Lactobacillus significantly decreased under different levels of ammonia exposure. We also observed positive associations of Faecalibacterium, Blautia, g__Ruminococcaceae_UCG-014, unclassified_f__Lachnospiraceae and Ruminococcus]_torques_group abundances with tracheal IL-1β concentration. Moreover, an increase in ammonia levels, even in 15 ppm, caused respiratory tract inflammatory injury. The results indicated that 15 ppm ammonia exposure changed the composition of tracheal microbiota that caused the tracheal injury possibly through increasing the IL-1β, which might make the broiler more sensitive to the changes of environment and pathogenic micro-organisms in the poultry house, and may be also a critical value that needs high alertness. Herein, the present experiment also suggested that the standard limit of ammonia concentration in adult poultry house is 15 ppm. This research provides an insight into the relationship between the upper respiratory tract microbiota and inflammation under ammonia exposure.
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Affiliation(s)
- Ying Zhou
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, State Key Laboratory of Animal Nutrition, Beijing, China
| | - Minhong Zhang
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, State Key Laboratory of Animal Nutrition, Beijing, China.
| | - Qingxiu Liu
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, State Key Laboratory of Animal Nutrition, Beijing, China
| | - Jinghai Feng
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, State Key Laboratory of Animal Nutrition, Beijing, China
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12
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Dayie NTKD, Osei MM, Opintan JA, Tetteh-Quarcoo PB, Kotey FCN, Ahenkorah J, Adutwum-Ofosu KK, Egyir B, Donkor ES. Nasopharyngeal Carriage and Antimicrobial Susceptibility Profile of Staphylococcus aureus among Children under Five Years in Accra. Pathogens 2021; 10:136. [PMID: 33572983 PMCID: PMC7912391 DOI: 10.3390/pathogens10020136] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/16/2021] [Accepted: 01/26/2021] [Indexed: 01/31/2023] Open
Abstract
This cross-sectional study investigated the Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA) nasopharyngeal carriage epidemiology in Accra approximately five years post-pneumococcal conjugate vaccines introduction in the country. Archived nasopharyngeal swabs collected from 410 children aged under five years old were bacteriologically cultured. The resultant S. aureus isolates were subjected to antimicrobial susceptibility testing and screening for carriage of the mecA and LukF-PV (pvl) genes, following standard procedures. The data obtained were analyzed with Statistical Products and Services Solutions (SPSS) using descriptive statistics and Chi square tests of associations. The isolated bacteria decreased across coagulase-negative Staphylococci (47.3%, n = 194), S. aureus (23.2%, n = 95), Diphtheroids (5.4%, n = 22), Micrococcus species (3.7%, n = 15), Klebsiella pneumoniae (3.2%, n = 13), Moraxella species and Citrobacter species (1.5% each, n = 6), Escherichia coli, Enterobacter species, and Pseudomonas species (0.9% each, n = 2). The MRSA carriage prevalence was 0.49% (n = 2). Individuals aged 37-48 months recorded the highest proportion of S. aureus carriage (32.6%, 31/95). Resistance of S. aureus to the antibiotics tested were penicillin G (97.9%, n = 93), amoxiclav (20%, n = 19), tetracycline (18.9%, n = 18), erythromycin (5.3%, n = 5), ciprofloxacin (2.1%, n = 2), gentamicin (1.1%, n = 1), cotrimoxazole, clindamycin, linezolid, and teicoplanin (0% each). No inducible clindamycin resistance was observed for the erythromycin-resistant isolates. Three (3.2%) of the isolates were multidrug resistant, of which 66.7% (2/3) were MRSA. The pvl gene was associated with 59.14% (55/93) of the methicillin-sensitive S. aureus (MSSA) isolates, but was not detected among any of the MRSA isolates.
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Affiliation(s)
- Nicholas T. K. D. Dayie
- Department of Medical Microbiology, University of Ghana Medical School, P.O. Box KB 4236 Accra, Ghana; (M.-M.O.); (J.A.O.); (P.B.T.-Q.); (F.C.N.K.); (E.S.D.)
| | - Mary-Magdalene Osei
- Department of Medical Microbiology, University of Ghana Medical School, P.O. Box KB 4236 Accra, Ghana; (M.-M.O.); (J.A.O.); (P.B.T.-Q.); (F.C.N.K.); (E.S.D.)
- FleRhoLife Research Consult, P.O. Box TS 853 Accra, Ghana
| | - Japheth A. Opintan
- Department of Medical Microbiology, University of Ghana Medical School, P.O. Box KB 4236 Accra, Ghana; (M.-M.O.); (J.A.O.); (P.B.T.-Q.); (F.C.N.K.); (E.S.D.)
| | - Patience B. Tetteh-Quarcoo
- Department of Medical Microbiology, University of Ghana Medical School, P.O. Box KB 4236 Accra, Ghana; (M.-M.O.); (J.A.O.); (P.B.T.-Q.); (F.C.N.K.); (E.S.D.)
| | - Fleischer C. N. Kotey
- Department of Medical Microbiology, University of Ghana Medical School, P.O. Box KB 4236 Accra, Ghana; (M.-M.O.); (J.A.O.); (P.B.T.-Q.); (F.C.N.K.); (E.S.D.)
- FleRhoLife Research Consult, P.O. Box TS 853 Accra, Ghana
| | - John Ahenkorah
- Department of Anatomy, University of Ghana Medical School, P.O. Box 4236 Accra, Ghana; (J.A.); (K.K.A.-O.)
| | - Kevin Kofi Adutwum-Ofosu
- Department of Anatomy, University of Ghana Medical School, P.O. Box 4236 Accra, Ghana; (J.A.); (K.K.A.-O.)
| | - Beverly Egyir
- Department of Bacteriology, Noguchi Memorial Institute for Medical Research, University of Ghana, P.O. Box LG 581 Accra, Ghana;
| | - Eric S. Donkor
- Department of Medical Microbiology, University of Ghana Medical School, P.O. Box KB 4236 Accra, Ghana; (M.-M.O.); (J.A.O.); (P.B.T.-Q.); (F.C.N.K.); (E.S.D.)
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Thibeault C, Suttorp N, Opitz B. The microbiota in pneumonia: From protection to predisposition. Sci Transl Med 2021; 13:13/576/eaba0501. [PMID: 33441423 DOI: 10.1126/scitranslmed.aba0501] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 06/30/2020] [Indexed: 12/12/2022]
Abstract
Mucosal surfaces of the upper respiratory tract and gut are physiologically colonized with their own collection of microbes, the microbiota. The normal upper respiratory tract and gut microbiota protects against pneumonia by impeding colonization by potentially pathogenic bacteria and by regulating immune responses. However, antimicrobial therapy and critical care procedures perturb the microbiota, thus compromising its function and predisposing to lung infections (pneumonia). Interindividual variations and age-related alterations in the microbiota also affect vulnerability to pneumonia. We discuss how the healthy microbiota protects against pneumonia and how host factors and medical interventions alter the microbiota, thus influencing susceptibility to pneumonia.
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Affiliation(s)
- Charlotte Thibeault
- Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, 13353 Berlin, Germany
| | - Norbert Suttorp
- Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, 13353 Berlin, Germany
| | - Bastian Opitz
- Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, 13353 Berlin, Germany.
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14
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Nasal Tissue Extraction Is Essential for Characterization of the Murine Upper Respiratory Tract Microbiota. mSphere 2020; 5:5/6/e00562-20. [PMID: 33328347 PMCID: PMC7771231 DOI: 10.1128/msphere.00562-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The nasal microbiota is composed of species that play a role in the colonization success of pathogens, including Streptococcus pneumoniae and Staphylococcus aureus. Murine models provide the ability to explore disease pathogenesis, but little is known about the natural murine nasal microbiota. Respiratory infections are a leading cause of morbidity and mortality worldwide. Bacterial pathogens often colonize the upper respiratory tract (nose or mouth) prior to causing lower respiratory infections or invasive disease. Interactions within the upper respiratory tract between colonizing bacteria and the resident microbiota could contribute to colonization success and subsequent transmission. Human carriage studies have identified associations between pathogens such as Streptococcus pneumoniae and members of the resident microbiota, although few mechanisms of competition and cooperation have been identified and would be aided by the use of animal models. Little is known about the composition of the murine nasal microbiota; thus, we set out to improve assessment, including tissue sampling, composition, and comparison between mouse sources. Nasal washes were efficient in sampling the nasopharyngeal space but barely disrupted the nasal turbinates. Nasal tissue extraction increased the yield of cultivable bacterial compared to nasal washes, revealing distinct community compositions. Experimental pneumococcal colonization led to dominance by the colonizing pathogen in the nasopharynx and nasal turbinates, but the composition of the microbiota, and interactions with resident microbes, differed depending on the sampling method. Importantly, vendor source has a large impact on microbial composition. Bacterial interactions, including cooperation and colonization resistance, depend on the biogeography of the nose and should be considered during research design of experimental colonization with pathogens. IMPORTANCE The nasal microbiota is composed of species that play a role in the colonization success of pathogens, including Streptococcus pneumoniae and Staphylococcus aureus. Murine models provide the ability to explore disease pathogenesis, but little is known about the natural murine nasal microbiota. This study established techniques to allow the exploration of the bacterial members of the nasal microbiota. The mouse nasal microbiota included traditional respiratory bacteria, including Streptococcus, Staphylococcus, and Moraxella species. Analyses were affected by different sampling methods as well as the commercial source of the mice, which should be included in future research design of infectious disease research.
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15
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Nyazika TK, Law A, Swarthout TD, Sibale L, Ter Braake D, French N, Heyderman RS, Everett D, Kadioglu A, Jambo KC, Neill DR. Influenza-like illness is associated with high pneumococcal carriage density in Malawian children. J Infect 2020; 81:549-556. [PMID: 32711042 PMCID: PMC7375306 DOI: 10.1016/j.jinf.2020.06.079] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 06/25/2020] [Accepted: 06/27/2020] [Indexed: 01/29/2023]
Abstract
Influenza-like illness (ILI) in children is associated with high pneumococcal carriage density. Children with ILI harboured more viral organisms than asymptomatic healthy children. Children with ILI patients had higher IL-8 levels in nasal aspirates than asymptomatic healthy children.
Background High pneumococcal carriage density is a risk factor for invasive pneumococcal disease (IPD) and transmission, but factors that increase pneumococcal carriage density are still unclear. Methods We undertook a cross-sectional study to evaluate the microbial composition, cytokine levels and pneumococcal carriage densities in samples from children presenting with an influenza-like illness (ILI) and asymptomatic healthy controls (HC). Results The proportion of children harbouring viral organisms (Relative risk (RR) 1.4, p = 0.0222) or ≥ 4 microbes at a time (RR 1.9, p < 0.0001), was higher in ILI patients than HC. ILI patients had higher IL-8 levels in nasal aspirates than HC (median [IQR], 265.7 [0 – 452.3] vs. 0 [0 – 127.3] pg/ml; p = 0.0154). Having an ILI was associated with higher pneumococcal carriage densities compared to HC (RR 4.2, p < 0.0001). Conclusion These findings suggest that children with an ILI have an increased propensity for high pneumococcal carriage density. This could in part contribute to increased susceptibility to IPD and transmission in the community.
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Affiliation(s)
- Tinashe K Nyazika
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Department of Pathology, College of Health Sciences, University of Malawi, Blantyre, Malawi.
| | - Alice Law
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Todd D Swarthout
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi; Division of Infection and Immunity, NIHR Global Health Research Unit on Mucosal Pathogens, University College London, London, United Kingdom
| | - Lusako Sibale
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi
| | - Danielle Ter Braake
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom; Department of Biomolecular Health Sciences, Division of Infectious Diseases & Immunology, Faculty of Veterinary Medicine, Utrecht, the Netherlands
| | - Neil French
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Robert S Heyderman
- Division of Infection and Immunity, NIHR Global Health Research Unit on Mucosal Pathogens, University College London, London, United Kingdom
| | - Dean Everett
- The Queens Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Aras Kadioglu
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Kondwani C Jambo
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
| | - Daniel R Neill
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
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16
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Cooper VS, Honsa E, Rowe H, Deitrick C, Iverson AR, Whittall JJ, Neville SL, McDevitt CA, Kietzman C, Rosch JW. Experimental Evolution In Vivo To Identify Selective Pressures during Pneumococcal Colonization. mSystems 2020; 5:e00352-20. [PMID: 32398278 PMCID: PMC7219553 DOI: 10.1128/msystems.00352-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 04/30/2020] [Indexed: 12/20/2022] Open
Abstract
Experimental evolution is a powerful technique to understand how populations evolve from selective pressures imparted by the surrounding environment. With the advancement of whole-population genomic sequencing, it is possible to identify and track multiple contending genotypes associated with adaptations to specific selective pressures. This approach has been used repeatedly with model species in vitro, but only rarely in vivo Herein we report results of replicate experimentally evolved populations of Streptococcus pneumoniae propagated by repeated murine nasal colonization with the aim of identifying gene products under strong selection as well as the population genetic dynamics of infection cycles. Frameshift mutations in one gene, dltB, responsible for incorporation of d-alanine into teichoic acids on the bacterial surface, evolved repeatedly and swept to high frequency. Targeted deletions of dltB produced a fitness advantage during initial nasal colonization coupled with a corresponding fitness disadvantage in the lungs during pulmonary infection. The underlying mechanism behind the fitness trade-off between these two niches was found to be enhanced adherence to respiratory cells balanced by increased sensitivity to host-derived antimicrobial peptides, a finding recapitulated in the murine model. Additional mutations that are predicted to affect trace metal transport, central metabolism, and regulation of biofilm production and competence were also selected. These data indicate that experimental evolution can be applied to murine models of pathogenesis to gain insight into organism-specific tissue tropisms.IMPORTANCE Evolution is a powerful force that can be experimentally harnessed to gain insight into how populations evolve in response to selective pressures. Herein we tested the applicability of experimental evolutionary approaches to gain insight into how the major human pathogen Streptococcus pneumoniae responds to repeated colonization events using a murine model. These studies revealed the population dynamics of repeated colonization events and demonstrated that in vivo experimental evolution resulted in highly reproducible trajectories that reflect the environmental niche encountered during nasal colonization. Mutations impacting the surface charge of the bacteria were repeatedly selected during colonization and provided a fitness benefit in this niche that was counterbalanced by a corresponding fitness defect during lung infection. These data indicate that experimental evolution can be applied to models of pathogenesis to gain insight into organism-specific tissue tropisms.
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Affiliation(s)
- Vaughn S Cooper
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Center for Evolutionary Biology and Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Erin Honsa
- St. Jude Children's Research Hospital, Department of Infectious Diseases, Memphis, Tennessee, USA
| | - Hannah Rowe
- St. Jude Children's Research Hospital, Department of Infectious Diseases, Memphis, Tennessee, USA
| | - Christopher Deitrick
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Center for Evolutionary Biology and Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Amy R Iverson
- St. Jude Children's Research Hospital, Department of Infectious Diseases, Memphis, Tennessee, USA
| | - Jonathan J Whittall
- Department of Molecular and Biomedical Science, School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Stephanie L Neville
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Christopher A McDevitt
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Colin Kietzman
- St. Jude Children's Research Hospital, Department of Infectious Diseases, Memphis, Tennessee, USA
| | - Jason W Rosch
- St. Jude Children's Research Hospital, Department of Infectious Diseases, Memphis, Tennessee, USA
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17
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Abstract
Streptococcus pneumoniae remains the most common bacterial pathogen causing lower respiratory tract infections and is a leading cause of morbidity and mortality worldwide, especially in children and the elderly. Another important aspect related to pneumococcal infections is the persistent rate of penicillin and macrolide resistance. Therefore, animal models have been developed to better understand the pathogenesis of pneumococcal disease and test new therapeutic agents and vaccines. This narrative review will focus on the characteristics of the different animal pneumococcal pneumonia models. The assessment of the different animal models will include considerations regarding pneumococcal strains, microbiology properties, procedures used for bacterial inoculation, pathogenesis, clinical characteristics, diagnosis, treatment, and preventive approaches.
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18
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de Steenhuijsen Piters WAA, Jochems SP, Mitsi E, Rylance J, Pojar S, Nikolaou E, German EL, Holloway M, Carniel BF, Chu MLJN, Arp K, Sanders EAM, Ferreira DM, Bogaert D. Interaction between the nasal microbiota and S. pneumoniae in the context of live-attenuated influenza vaccine. Nat Commun 2019; 10:2981. [PMID: 31278315 PMCID: PMC6611866 DOI: 10.1038/s41467-019-10814-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 05/15/2019] [Indexed: 12/21/2022] Open
Abstract
Streptococcus pneumoniae is the main bacterial pathogen involved in pneumonia. Pneumococcal acquisition and colonization density is probably affected by viral co-infections, the local microbiome composition and mucosal immunity. Here, we report the interactions between live-attenuated influenza vaccine (LAIV), successive pneumococcal challenge, and the healthy adult nasal microbiota and mucosal immunity using an experimental human challenge model. Nasal microbiota profiles at baseline are associated with consecutive pneumococcal carriage outcome (non-carrier, low-dense and high-dense pneumococcal carriage), independent of LAIV co-administration. Corynebacterium/Dolosigranulum-dominated profiles are associated with low-density colonization. Lowest rates of natural viral co-infection at baseline and post-LAIV influenza replication are detected in the low-density carriers. Also, we detected the fewest microbiota perturbations and mucosal cytokine responses in the low-density carriers compared to non-carriers or high-density carriers. These results indicate that the complete respiratory ecosystem affects pneumococcal behaviour following challenge, with low-density carriage representing the most stable ecological state.
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Affiliation(s)
- Wouter A A de Steenhuijsen Piters
- Department of Paediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital/University Medical Center Utrecht, Lundlaan 6, Utrecht, 3584 EA, The Netherlands
- Department of Medical Microbiology, University Medical Center Utrecht, Heidelberglaan 100, Utrecht, 3584 CX, The Netherlands
- Medical Research Council/University of Edinburgh Centre for Inflammation Research, Queen's Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, United Kingdom
| | - Simon P Jochems
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, United Kingdom
| | - Elena Mitsi
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, United Kingdom
| | - Jamie Rylance
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, United Kingdom
| | - Sherin Pojar
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, United Kingdom
| | - Elissavet Nikolaou
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, United Kingdom
| | - Esther L German
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, United Kingdom
| | - Mark Holloway
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, United Kingdom
| | - Beatriz F Carniel
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, United Kingdom
| | - Mei Ling J N Chu
- Department of Paediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital/University Medical Center Utrecht, Lundlaan 6, Utrecht, 3584 EA, The Netherlands
- Department of Medical Microbiology, University Medical Center Utrecht, Heidelberglaan 100, Utrecht, 3584 CX, The Netherlands
| | - Kayleigh Arp
- Department of Paediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital/University Medical Center Utrecht, Lundlaan 6, Utrecht, 3584 EA, The Netherlands
- Department of Medical Microbiology, University Medical Center Utrecht, Heidelberglaan 100, Utrecht, 3584 CX, The Netherlands
| | - Elisabeth A M Sanders
- Department of Paediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital/University Medical Center Utrecht, Lundlaan 6, Utrecht, 3584 EA, The Netherlands
| | - Daniela M Ferreira
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, United Kingdom
| | - Debby Bogaert
- Department of Paediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital/University Medical Center Utrecht, Lundlaan 6, Utrecht, 3584 EA, The Netherlands.
- Department of Medical Microbiology, University Medical Center Utrecht, Heidelberglaan 100, Utrecht, 3584 CX, The Netherlands.
- Medical Research Council/University of Edinburgh Centre for Inflammation Research, Queen's Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, United Kingdom.
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A longitudinal characterization of the Non-Cystic Fibrosis Bronchiectasis airway microbiome. Sci Rep 2019; 9:6871. [PMID: 31053725 PMCID: PMC6499777 DOI: 10.1038/s41598-019-42862-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 04/08/2019] [Indexed: 12/30/2022] Open
Abstract
A diverse microbiota exists within the airways of individuals with non-cystic fibrosis bronchiectasis (nCFB). How the lung microbiome evolves over time, and whether changes within the microbiome correlate with future disease progression is not yet known. We assessed the microbial community structure of 133 serial sputa and subsequent disease course of 29 nCFB patients collected over a span of 4–16 years using 16S rRNA paired-end sequencing. Interestingly, no significant shifts in the microbial community of individuals were observed during extended follow-up suggesting the microbiome remains relatively stable over prolonged periods. Samples that were Pseudomonas aeruginosa culture positive displayed markedly different microbial community structures compared to those that were positive for Haemophilus influenzae. Importantly, patients with sputum of lower microbial community diversity were more likely to experience subsequent lung function decline as defined by annual change in ≥−1 FEV1% predicted. Shannon diversity values <1 were more prevalent in patients with FEV1 decline (P = 0.002). However, the relative abundance of particular core microbiota constituents did not associate with risk of decline. Here we present data confirming that the microbiome of nCFB individuals is generally stable, and that microbiome-based measurements may have a prognostic role as biomarkers for nCFB.
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20
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Frasca D, McElhaney J. Influence of Obesity on Pneumococcus Infection Risk in the Elderly. Front Endocrinol (Lausanne) 2019; 10:71. [PMID: 30814978 PMCID: PMC6381016 DOI: 10.3389/fendo.2019.00071] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 01/24/2019] [Indexed: 12/16/2022] Open
Abstract
Obesity negatively affects immune function and host defense mechanisms. Obesity is associated with chronic activation of the innate immune system and consequent local and systemic inflammation which contribute to pathologic conditions such as type-2 diabetes mellitus, cancer, psoriasis, atherosclerosis, and inflammatory bowel disease. Individuals with obesity have increased susceptibility to contract viral, bacterial, and fungal infections and respond sub-optimally to vaccination. In this review, we summarize research findings on the effects of obesity on immune responses to respiratory tract infections (RTI), focusing on Streptococcus pneumoniae ("pneumococcus") infection, which is a major cause of morbidity and mortality in the US, causing community-acquired infections such as pneumonia, otitis media and meningitis. We show that the risk of infection is higher in elderly individuals and also in individuals of certain ethnic groups, although in a few reports obesity has been associated with better survival of individuals admitted to hospital with pneumococcus infection, a phenomenon known as "obesity paradox." We discuss factors that are associated with increased risk of pneumococcal infection, such as recent infection with RTI, chronic medical conditions, and immunosuppressive medications.
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Affiliation(s)
- Daniela Frasca
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Janet McElhaney
- Health Sciences North Research Institute, Sudbury, ON, Canada
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21
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Abstract
The microbiome is defined as the total of cellular microorganisms of baczerial, viral or e. g., parasite origin living on the surface of a body. Within the anatomical areas of otorhinolaryngology, a significant divergence and variance can be demonstrated. For ear, nose, throat, larynx and cutis different interactions of microbiome and common factors like age, diet and live style factors (e. g., smoking) have been detected in recent years. Besides, new insights hint at a passible pathognomic role of the microbiome towards diseases in the ENT area. This review article resumes the present findings of this rapidly devloping scientific area.
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Affiliation(s)
- Achim G Beule
- HNO-Uniklinik Münster.,Klinik und Poliklinik für Hals-Nasen-Ohrenkrankheiten der Universitätsmedizin Greifswald
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22
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Cho SJ, Rooney K, Choi AMK, Stout-Delgado HW. NLRP3 inflammasome activation in aged macrophages is diminished during Streptococcus pneumoniae infection. Am J Physiol Lung Cell Mol Physiol 2018; 314:L372-L387. [PMID: 29097427 PMCID: PMC5900358 DOI: 10.1152/ajplung.00393.2017] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 10/17/2017] [Accepted: 10/17/2017] [Indexed: 11/22/2022] Open
Abstract
Pneumococcal infections are the eigth leading cause of death in the United States, and it is estimated that older patients (≥65 yr of age) account for the most serious cases. The goal of our current study is to understand the impact of biological aging on innate immune responses to Streptococcus pneumoniae, a causative agent of bacterial pneumonia. With the use of in vitro and in vivo aged murine models, our findings demonstrate that age-enhanced unfolded protein responses (UPRs) contribute to diminished inflammasome assembly and activation during S. pneumoniae infection. Pretreatment of aged mice with endoplasmic reticulum chaperone and the stress-reducing agent tauroursodeoxycholic acid (TUDCA) decreased mortality in aged hosts that was associated with increased NLRP3 inflammasome activation, improved pathogen clearance, and decreased pneumonitis during infection. Taken together, our data provide new evidence as to why older persons are more susceptible to S. pneumoniae and provide a possible therapeutic target to decrease morbidity and mortality in this population.
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Affiliation(s)
- Soo Jung Cho
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Weill Cornell Medicine , New York, New York
| | - Kristen Rooney
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Weill Cornell Medicine , New York, New York
| | - Augustine M K Choi
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Weill Cornell Medicine , New York, New York
| | - Heather W Stout-Delgado
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Weill Cornell Medicine , New York, New York
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23
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The lung microbiome. Emerg Top Life Sci 2017; 1:313-324. [PMID: 33525774 DOI: 10.1042/etls20170043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Revised: 08/31/2017] [Accepted: 09/29/2017] [Indexed: 12/17/2022]
Abstract
Historically, our understanding of lung microbiology has relied on insight gained through culture-based diagnostic approaches that employ selective culture conditions to isolate specific pathogens. The relatively recent development of culture-independent microbiota-profiling techniques, particularly 16S rRNA (ribosomal ribonucleic acid) gene amplicon sequencing, has enabled more comprehensive characterisation of the microbial content of respiratory samples. The widespread application of such techniques has led to a fundamental shift in our view of respiratory microbiology. Rather than a sterile lung environment that can become colonised by microbes during infection, it appears that a more nuanced balance exists between what we consider respiratory health and disease, mediated by mechanisms that influence the clearance of microbes from the lungs. Where airway defences are compromised, the ongoing transient exposure of the lower airways to microbes can lead to the establishment of complex microbial communities within the lung. Importantly, the characteristics of these communities, and the manner in which they influence lung pathogenesis, can be very different from those of their constituent members when viewed in isolation. The lung microbiome, a construct that incorporates microbes, their genetic material, and the products of microbial genes, is increasingly central to our understanding of the regulation of respiratory physiology and the processes that underlie lung pathogenesis.
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24
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The nasopharyngeal microbiome. Emerg Top Life Sci 2017; 1:297-312. [PMID: 33525776 DOI: 10.1042/etls20170041] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 10/19/2017] [Accepted: 10/20/2017] [Indexed: 02/07/2023]
Abstract
Human microbiomes have received increasing attention over the last 10 years, leading to a pervasiveness of hypotheses relating dysbiosis to health and disease. The respiratory tract has received much less attention in this respect than that of, for example, the human gut. Nevertheless, progress has been made in elucidating the immunological, ecological and environmental drivers that govern these microbial consortia and the potential consequences of aberrant microbiomes. In this review, we consider the microbiome of the nasopharynx, a specific niche of the upper respiratory tract. The nasopharynx is an important site, anatomically with respect to its gateway position between upper and lower airways, and for pathogenic bacterial colonisation. The dynamics of the latter are important for long-term respiratory morbidity, acute infections of both invasive and non-invasive disease and associations with chronic airway disease exacerbations. Here, we review the development of the nasopharyngeal (NP) microbiome over the life course, examining it from the early establishment of resilient profiles in neonates through to perturbations associated with pneumonia risk in the elderly. We focus specifically on the commensal, opportunistically pathogenic members of the NP microbiome that includes Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae and Moraxella catarrhalis. In addition, we consider the role of relatively harmless genera such as Dolosigranulum and Corynebacterium. Understanding that the NP microbiome plays such a key, beneficial role in maintaining equilibrium of commensal species, prevention of pathogen outgrowth and host immunity enables future research to be directed appropriately.
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25
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Abstract
With the coming of the "silver tsunami," expanding the knowledge about how various intrinsic and extrinsic factors affect the immune system in the elderly is timely and of immediate clinical need. The global population is increasing in age. By the year 2030, more than 20% of the population of the United States will be older than 65 years of age. This article focuses on how advanced age alters the immune systems and how this, in turn, modulates the ability of the aging lung to deal with infectious challenges from the outside world and from within the host.
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Affiliation(s)
- Elizabeth J Kovacs
- Division of GI, Trauma and Endocrine Surgery, Department of Surgery, Mucosal Inflammation Program, GILIIP (GI, Liver and Innate Immunity Program), Graduate Program in Immunology, IMAGE (Investigations in Metabolism, Aging, Gender and Exercise), University of Colorado Denver, Anschutz Medical Campus, 12700 East 19th Avenue, Research Complex 2, Mailstop #8620, Aurora, CO 80045, USA.
| | - Devin M Boe
- Division of GI, Trauma and Endocrine Surgery, Department of Surgery, Mucosal Inflammation Program, Graduate Program in Immunology, University of Colorado Denver, Anschutz Medical Campus, 12700 East 19th Avenue, Research Complex 2, Room 6460, Aurora, CO 80045, USA
| | - Lisbeth A Boule
- Division of GI, Trauma and Endocrine Surgery, Department of Surgery, Mucosal Inflammation Program, IMAGE, University of Colorado Denver, Anschutz Medical Campus, 12700 East 19th Avenue, Research Complex 2, Room 6460, Aurora, CO 80045, USA
| | - Brenda J Curtis
- Division of GI, Trauma and Endocrine Surgery, Department of Surgery, Mucosal Inflammation Program, IMAGE, University of Colorado Denver, Anschutz Medical Campus, 12700 East 19th Avenue, Research Complex 2, Room 6018, Aurora, CO 80045, USA
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26
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Streptococcus pneumoniae Colonization Is Required To Alter the Nasal Microbiota in Cigarette Smoke-Exposed Mice. Infect Immun 2017; 85:IAI.00434-17. [PMID: 28760931 DOI: 10.1128/iai.00434-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 07/24/2017] [Indexed: 12/26/2022] Open
Abstract
Smokers have nasal microbiota dysbiosis, with an increased frequency of colonizing bacterial pathogens. It is possible that cigarette smoke increases pathogen acquisition by perturbing the microbiota and decreasing colonization resistance. However, it is difficult to disentangle microbiota dysbiosis due to cigarette smoke exposure from microbiota changes caused by increased pathogen acquisition in human smokers. Using an experimental mouse model, we investigated the impact of cigarette smoke on the nasal microbiota in the absence and presence of nasal pneumococcal colonization. We observed that cigarette smoke exposure alone did not alter the nasal microbiota composition. The microbiota composition was also unchanged at 12 h following low-dose nasal pneumococcal inoculation, suggesting that the ability of the microbiota to resist initial nasal pneumococcal acquisition was not impaired in smoke-exposed mice. However, nasal microbiota dysbiosis occurred as a consequence of established high-dose nasal pneumococcal colonization at day 3 in smoke-exposed mice. Similar to clinical reports on human smokers, an enrichment of potentially pathogenic bacterial genera such as Fusobacterium, Gemella, and Neisseria was observed. Our findings suggest that cigarette smoke exposure predisposes to pneumococcal colonization independent of changes to the nasal microbiota and that microbiota dysbiosis observed in smokers may occur as a consequence of established pathogen colonization.
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27
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Boe DM, Boule LA, Kovacs EJ. Innate immune responses in the ageing lung. Clin Exp Immunol 2016; 187:16-25. [PMID: 27711979 DOI: 10.1111/cei.12881] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2016] [Indexed: 12/19/2022] Open
Abstract
The world is undergoing an unprecedented shift in demographics, with the number of individuals over the age of 60 years projected to reach 2 billion or more by 2050, representing 22% of the global population. Elderly people are at a higher risk for chronic disease and more susceptible to infection, due in part to age-related dysfunction of the immune system resulting from low-grade chronic inflammation known as 'inflamm-ageing'. The innate immune system of older individuals exhibits a diminished ability to respond to microbial threats and clear infections, resulting in a greater occurrence of many infectious diseases in elderly people. In particular, the incidence of and mortality from lung infections increase sharply with age, with such infections often leading to worse outcomes, prolonged hospital stays and life-threatening complications, such as sepsis or acute respiratory distress syndrome. In this review, we highlight research on bacterial pneumonias and pulmonary viral infections and discuss age-related changes in innate immunity that contribute to the higher rate of these infections in older populations. By understanding more clearly the innate immune defects in elderly individuals, we can design age-specific therapies to address lung infections in such a vulnerable population.
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Affiliation(s)
- D M Boe
- Division of GI, Endocrine and Tumor Surgery, Department of Surgery, Mucosal Inflammation Program, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, USA
| | - L A Boule
- Division of GI, Endocrine and Tumor Surgery, Department of Surgery, Mucosal Inflammation Program, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, USA
| | - E J Kovacs
- Division of GI, Endocrine and Tumor Surgery, Department of Surgery, Mucosal Inflammation Program, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, USA
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28
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Schenck LP, Surette MG, Bowdish DME. Composition and immunological significance of the upper respiratory tract microbiota. FEBS Lett 2016; 590:3705-3720. [PMID: 27730630 PMCID: PMC7164007 DOI: 10.1002/1873-3468.12455] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 09/30/2016] [Accepted: 10/07/2016] [Indexed: 11/13/2022]
Abstract
The intestinal microbiota is essential for nutrient acquisition, immune development, and exclusion of invading pathogens. The upper respiratory tract (URT) microbiota is less well studied and does not appear to abide by many of the paradigms of the gastrointestinal tract. Decades of carriage studies in children have demonstrated that microbe–microbe competition and collusion occurs in the URT. Whether colonization with common pathogens (e.g., Staphylococcus aureus and Streptococcus pneumoniae) alters immune development or susceptibility to respiratory conditions is just beginning to be understood. Herein, we discuss the biogeography of the URT microbiota, the succession and evolution of the microbiota through the life course, and discuss the evidence for microbe–microbe interactions in colonization and infection.
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Affiliation(s)
- Louis Patrick Schenck
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada
| | - Michael G Surette
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada.,Department of Medicine, McMaster University, Hamilton, Canada
| | - Dawn M E Bowdish
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada.,Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
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