Methods: To investigate the relationship between CPS antibody levels and oropharyngeal bacterial community composition, we collected oropharyngeal swabs from 55 subjects before and after PCV13 vaccination, extracted DNA, and performed high-density (Illumina MiSeq) sequencing of the 16S rRNA gene’s V1-V2 hypervariable region. Oropharyngeal community types were identified by species-level Dirichlet-multinomial mixture modeling (Laplace approximation to model evidence) and compared to antibody levels (Kruskal-Wallis test).
Results: Two oropharyngeal community types were identified, distinguished primarily by relative abundance of Prevotella melaninogenica and several Streptococcus species. Type 1, characterized by greater abundance of Prevotella melaninogenica, Streptococcus cristatus and infantis, was associated with significantly higher baseline and post-vaccination CPS IgM/IgG; type 2, characterized by greater proportional abundance of Streptococcus salivarius and parasanguinis, with lower baseline and post-vaccination CPS IgM/IgG (Bonferroni-corrected p-values < 0.026).
Conclusion: In a cohort of HIV-infected subjects, oropharyngeal bacterial community type was correlated with CPS antibody levels pre- and post-PCV13. The interaction between the oropharyngeal bacterial microbiome (particularly non-pneumococcal Streptococcus species) and pneumococcal vaccine response warrants further investigation.
L. A. Pirofski, None