title: Streptococcus pneumoniae Colonization Disrupts the Microbial Community within the Upper Respiratory Tract of Aging Mice.
abstract: Nasopharyngeal colonization by the Gram-positive bacterium Streptococcus pneumonia is a prerequisite for pneumonia and invasive pneumococcal diseases. Colonization is asymptomatic, involving dynamic and complex interplay between commensals, the host immune system, and environmental factors. The elderly are at an increased risk of developing pneumonia, which might be due to changes in the respiratory microbiota that would impact bacterial colonization and persistence within this niche. We hypothesized that the composition of the upper respiratory tract (URT) microbiota changes with age and subsequently can contribute to sustained colonization and inefficient clearance of S. pneumoniae To test this, we used a mouse model of pneumococcal colonization to compare the composition of the URT microbiota in young, middle-aged, and old mice in the naive state and during the course of colonization using nasal pharyngeal washes. Sequencing of variable region 3 (V3) of the 16S rRNA gene was used to identify changes occurring with age and throughout the course of S. pneumonia colonization. We discovered that age affects the composition of the URT microbiota and that colonization with S. pneumoniae is more disruptive of preexisting communities in older mice. We have further shown that host-pathogen interactions followingS. pneumonia colonization can impact the populations of resident microbes, including Staphylococcus and Haemophilus. Together, our findings indicate alterations to the URT microbiota could be detrimental to the elderly, resulting in increased colonization of S. pneumonia and decreased efficiency in its clearance.
authors.affiliation: Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada McMaster Immunology Research Centre, McMaster University, Hamilton, Canada Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada.
authors.forename: Netusha
authors.initials: N
authors.lastname: Thevaranjan
authors.affiliation: Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Canada Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada.
authors.forename: Fiona J
authors.initials: FJ
authors.lastname: Whelan
authors.affiliation: Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada McMaster Immunology Research Centre, McMaster University, Hamilton, Canada Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada.
authors.forename: Alicja
authors.initials: A
authors.lastname: Puchta
authors.affiliation: Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada McMaster Immunology Research Centre, McMaster University, Hamilton, Canada Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada.
authors.forename: Eta
authors.initials: E
authors.lastname: Ashu
authors.affiliation: Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Canada.
authors.forename: Laura
authors.initials: L
authors.lastname: Rossi
authors.affiliation: Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Canada Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada Department of Medicine, McMaster University, Hamilton, Canada.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Surette
authors.affiliation: Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada McMaster Immunology Research Centre, McMaster University, Hamilton, Canada Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada bowdish@mcmaster.ca.
authors.forename: Dawn M E
authors.initials: DM
authors.lastname: Bowdish
mesh_terms: D000375:Aging; D000818:Animals; D002353:Carrier State; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D064307:Microbiota / Q000235:genetics; D009305:Nasopharynx / Q000382:microbiology*; D013047:Specific Pathogen-Free Organisms; D013296:Streptococcus pneumoniae / Q000502:physiology*; D013997:Time Factors