Pneumococcal Surface Protein A Contributes to Secondary Streptococcus pneumoniae Infection following Influenza Infection

• Published in: The Journal of infectious diseases 2009-08, Vol.200 (4), p.537-545
• Main Authors: King, Quinton O., Lei, Benfang, Harmsen, Allen G.
• Format: Article
• Language: English
• ISSN: 0022-1899; 1537-6613
• DOI: 10.1086/600871

We compared growth of Streptococcus pneumoniae mutants with disruption in the pspA (PspA-), nanA (NanA-) or hyl (Hyl-) gene to the parental D39 strain using a competitive growth model in mice with and without prior influenza infection. Total bacteria numbers recovered from influenza-infected mice were significantly greater compared to mice without influenza infection. Whereas Hyl- and NanA- mutants did not display attenuation in mice with or without prior influenza infection, the PspA- mutant exhibited attenuation in mice both with and without influenza infection. This defect was severe influenza-infected mice where PspA- growth was 1800-fold less than D39. Furthermore, PspA immunization significantly reduced secondary bacterial lung burdens and specific markers of lung damage in mice receiving serotypes 2, 3 and 4 pneumococci. Our findings indicate that PspA contributes to secondary S. pneumoniae infection following influenza and that PspA immunization mitigates early secondary pneumococcal lung infections.