3 Key Takeaways
Plain English Summary- 01Core Finding
We analyzed the cPS of serogroup 15 pneumococcal isolates and isogenic recombinant strains whose capsule synthesis loci vary by integrity of putative O-acetyltransferase (OAcT) genes wcjE or wciZ. cPS biochemical structures were compared in nuclear magnetic resonance and serotyping experiments.
- 02Study Evidence
Tested in a standard-of-care clinical practice · clinical evidence review at the clinical practice stage.
- 03Practical Meaning
Benefits and risks vary by individual health history — discuss with a healthcare professional.
What This Means for You
15D and 15z cPS contain either WciZ-mediated or WcjE-mediated O-acetylation, respectively, while 15F contains both. Current typing schemes may not reliably resolve variants of vaccine serotypes, but we highlight how an anticipatory approach to capsule type discovery can address typing blind spots and refine vaccine surveillance efforts.
The Discovery
Streptococcus pneumoniae vaccine efforts rely on serological or molecular typing schemes to categorize over 100 biochemically distinct capsule polysaccharides (cPS) produced by the pathobiont; however, conventional approaches can fail to capture variations in key cPS biochemical features, such O-acetylation (OAc) patterns. The non-acetylated serotype 15A cPS is included in newer pneumococcal conjugate vaccine formulations and has one characterized acetylated counterpart, 15F. Report of a potential second variant "15D" prompted re-investigation of serogroup 15 capsule types. We analyzed the cPS of serogroup 15 pneumococcal isolates and isogenic recombinant strains whose capsule synthesis loci vary by integrity of putative O-acetyltransferase (OAcT) genes wcjE or wciZ. cPS biochemical structures were compared in nuclear magnetic resonance and serotyping experiments. Computational analysis screened for novel serogroup 15 OAc variants in a curated pneumococcal genome database. The cPS biochemical structures of 15A, 15F, 15D and a novel type 15z differed according to their unique OAc pattern. While available serotyping antisera distinguished capsule types 15D from 15A and 15z from 15F, capsule types 15F/15D and 15z/15A were indistinguishable. We identified serotype "15A" and "15F" isolates molecularly typed as "15F" in prior work, but predicted to encode 15z or 15D cPS according to their OAcT gene content.
How It Works, Simply
This infectious disease research focuses on genetics. Researchers evaluated it using a standard-of-care clinical practice · Clinical evidence review at the clinical practice stage of medical research.
3 Key Takeaways
Clinical Takeaways- 01Core Finding
We analyzed the cPS of serogroup 15 pneumococcal isolates and isogenic recombinant strains whose capsule synthesis loci vary by integrity of putative O-acetyltransferase (OAcT) genes wcjE or wciZ. cPS biochemical structures were compared in nuclear magnetic resonance and serotyping experiments.
- 02Study Evidence
Tested in a standard-of-care clinical practice · clinical evidence review at the clinical practice stage.
- 03Practical Meaning
Benefits and risks vary by individual health history — discuss with a healthcare professional.
Biological Mechanism & Study Design
Study Design & Cohort
Clinical evidence review
Standard-of-care clinical practice · Clinical evidence review · Clinical Practice
Biological Pathway & Modality
Genetics
Intervention: O-acetylation mediates four distinct structural variants of the pneumococcal vaccine
Experimental Findings & Endpoints
Streptococcus pneumoniae vaccine efforts rely on serological or molecular typing schemes to categorize over 100 biochemically distinct capsule polysaccharides (cPS) produced by the pathobiont; however, conventional approaches can fail to capture variations in key cPS biochemical features, such O-acetylation (OAc) patterns.
The non-acetylated serotype 15A cPS is included in newer pneumococcal conjugate vaccine formulations and has one characterized acetylated counterpart, 15F. Report of a potential second variant "15D" prompted re-investigation of serogroup 15 capsule types.
We analyzed the cPS of serogroup 15 pneumococcal isolates and isogenic recombinant strains whose capsule synthesis loci vary by integrity of putative O-acetyltransferase (OAcT) genes wcjE or wciZ. cPS biochemical structures were compared in nuclear magnetic resonance and serotyping experiments. Computational analysis screened for novel serogroup 15 OAc variants in a curated pneumococcal genome database.
The cPS biochemical structures of 15A, 15F, 15D and a novel type 15z differed according to their unique OAc pattern. While available serotyping antisera distinguished capsule types 15D from 15A and 15z from 15F, capsule types 15F/15D and 15z/15A were indistinguishable.
We identified serotype "15A" and "15F" isolates molecularly typed as "15F" in prior work, but predicted to encode 15z or 15D cPS according to their OAcT gene content.
Clinical Translation & Practice Context
15D and 15z cPS contain either WciZ-mediated or WcjE-mediated O-acetylation, respectively, while 15F contains both.
Current typing schemes may not reliably resolve variants of vaccine serotypes, but we highlight how an anticipatory approach to capsule type discovery can address typing blind spots and refine vaccine surveillance efforts.
The Bottom Line · Clinical Pearl
“15D and 15z cPS contain either WciZ-mediated or WcjE-mediated O-acetylation, respectively, while 15F contains both.”
Published in The Journal of Infectious Diseases · Current Stage: Clinical Practice