title: Influenza A virus alters pneumococcal nasal colonization and middle ear infection independently of phase variation.
abstract: Streptococcus pneumoniae (pneumococcus) is both a widespread nasal colonizer and a leading cause of otitis media, one of the most common diseases of childhood. Pneumococcal phase variation influences both colonization and disease and thus has been linked to the bacteria's transition from colonizer to otopathogen. Further contributing to this transition, coinfection with influenza A virus has been strongly associated epidemiologically with the dissemination of pneumococci from the nasopharynx to the middle ear. Using a mouse infection model, we demonstrated that coinfection with influenza virus and pneumococci enhanced both colonization and inflammatory responses within the nasopharynx and middle ear chamber. Coinfection studies were also performed using pneumococcal populations enriched for opaque or transparent phase variants. As shown previously, opaque variants were less able to colonize the nasopharynx. In vitro, this phase also demonstrated diminished biofilm viability and epithelial adherence. However, coinfection with influenza virus ameliorated this colonization defect in vivo. Further, viral coinfection ultimately induced a similar magnitude of middle ear infection by both phase variants. These data indicate that despite inherent differences in colonization, the influenza A virus exacerbation of experimental middle ear infection is independent of the pneumococcal phase. These findings provide new insights into the synergistic link between pneumococcus and influenza virus in the context of otitis media.
authors.affiliation: Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.
authors.forename: John T
authors.initials: JT
authors.lastname: Wren
authors.affiliation: Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.
authors.forename: Lance K
authors.initials: LK
authors.lastname: Blevins
authors.affiliation: Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.
authors.forename: Bing
authors.initials: B
authors.lastname: Pang
authors.affiliation: Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.
authors.forename: Lauren B
authors.initials: LB
authors.lastname: King
authors.affiliation: Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.
authors.forename: Antonia C
authors.initials: AC
authors.lastname: Perez
authors.affiliation: Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.
authors.forename: Kyle A
authors.initials: KA
authors.lastname: Murrah
authors.affiliation: Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Reimche
authors.affiliation: Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.
authors.forename: Martha A
authors.initials: MA
authors.lastname: Alexander-Miller
authors.affiliation: Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA wswords@wakehealth.edu.
authors.forename: W Edward
authors.initials: WE
authors.lastname: Swords
mesh_terms: D000818:Animals; D002353:Carrier State; D060085:Coinfection; D009980:Influenza A virus; D051379:Mice; D009666:Nose / Q000382:microbiology*; D009976:Orthomyxoviridae Infections / Q000150:complications*; D010033:Otitis Media / Q000150:complications / Q000382:microbiology*; D011008:Pneumococcal Infections / Q000150:complications / Q000382:microbiology*; D013296:Streptococcus pneumoniae / Q000502:physiology*