Mar 4, 2015

Nonencapsulated Streptococcus pneumoniae Cause Acute Otitis Media in the Chinchilla That Is Enhanced by Pneumococcal Surface Protein K

Open Forum Infectious Diseases
Lance E KellerLarry S McDaniel

Abstract

Use of the pneumococcal conjugate vaccine has led to serotype replacement of carriage and acute otitis media (AOM) pneumococcal isolates. Increases in nonencapsulated Streptococcus pneumoniae (NESp) isolates have also occurred, and there are increasing reports of NESp-associated disease. Disease prevalence and virulence factors of NESp isolates have not been studied. A chinchilla model of pneumococcal AOM was utilized, and disease was assessed through bacterial enumeration along with scoring visible signs of pathology. An adhesion-invasion assay using a human epithelial cell line was performed. Nonencapsulated Streptococcus pneumoniae strains containing pneumococcal surface protein K (PspK) were more likely to cause AOM and pathology upon infection. Deletion of PspK from an isolate significantly reduced bacterial loads. Increased epithelial cell adhesion correlated with increased virulence of NESp isolates naturally lacking PspK. Furthermore, expression of PspK by an avirulent NESp resulted in virulence. The presence of PspK increased the disease potential of NESp. Pneumococcal surface protein K is not the only virulence factor of NESp in AOM. Expression of PspK in an avirulent NESp mediated the progression to pneumococcal dise...Continue Reading

  • References32
  • Citations14

References

  • References32
  • Citations14

Citations

Mentioned in this Paper

Study
GNAS gene
Associative Aphasia
Pneumococcal surface protein A
Gene Deletion Abnormality
Gene Deletion
Chinchilla<genus>
Isolate compound
GNAS wt Allele
Deletion Mutation

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