Global distribution of invasive serotype 35D streptococcus pneumoniae isolates following introduction of 13-valent pneumococcal conjugate vaccine

Authors

Stephanie W. Lo, The Wellcome Trust Sanger Institute
Rebecca A. Gladstone, The Wellcome Trust Sanger Institute
Andries J. van Tonder, Rollins School of Public Health
Paulina A. Hawkins, Centers for Disease Control and Prevention
Brenda Kwambana Adams, Medical Research Council Unit The Gambia
Jennifer E. Cornick, University of Liverpool
Shabir A. Madhi, University of the Witwatersrand, Johannesburg
Susan A. Nzenze, University of the Witwatersrand, Johannesburg
Mignon du Plessis, Centre for Respiratory Disease and Meningitis
Rama Kandasamy, University of Oxford, and the NIHR Oxford Biomedical Research Centre
Philip E. Carter, Kenepuru Science Centre
Sadia Shakoor, Aga Khan UniversityFollow

Document Type

Article

Department

Pathology and Microbiology

Abstract

A newly recognized pneumococcal serotype 35D, which differs from the 35B polysaccharide in structure and serology by not binding to factor serum 35a, was recently reported. The genetic basis for this distinctive serology is due to the presence of an inactivating mutation in wciG, which encodes an O-acetyltransferase responsible for O-acetylation of a galactofuranose. Here, we assessed the genomic data of a worldwide pneumococcal collection to identify serotype 35D isolates and understand their geographical distribution, genetic background and invasiveness potential. Of 21,980 pneumococcal isolates, 444 were originally typed as serotype 35B by PneumoCaT. Analysis of wciGrevealed 23 isolates from carriage (n=4) and disease (n=19) with partial or complete loss-of-funtion mutations, including mutations resulting in pre-mature stop codons (n=22) and an in-frame mutation (n=1). These were selected for further analysis. The putative 35D isolates were geographically widespread and 65.2% (15/23) of them was recovered after PCV13 introduction. Compared with serotype 35B, putative serotype 35D isolates have higher invasive disease potentials based on odds ratio (OR) (11.58; 95% CI, 1.42-94.19 vs 0.61; 95% CI, 0.40-0.92) and a higher prevalence of macrolide resistance mediated by mefA (26.1% vs 7.6%, p=0.009). Using Quellung, 50% (10/20) of viable isolates were serotype 35D, 25% (5/20) serotype 35B, and 25% (5/20) a mixture of 35B/35D. The discrepancy between phenotype and genotype requires further investigation. These findings illustrated a global distribution of an invasive serotype 35D among young children post-PCV13 introduction and underlined the invasive potential conferred by the loss of O-acetylation in the pneumococcal capsule.

Comments

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Author copy

Publication (Name of Journal)

Journal of Clinical Microbiology

Recommended Citation

Lo, S. W., Gladstone, R. A., van Tonder, A. J., Hawkins, P. A., Adams, B. K., Cornick, J. E., Madhi, S. A., Nzenze, S. A., Plessis, M. d., Kandasamy, R., Carter, P. E., Shakoor, S. (2018). Global distribution of invasive serotype 35D streptococcus pneumoniae isolates following introduction of 13-valent pneumococcal conjugate vaccine. Journal of Clinical Microbiology, 56(7), e00228.
Available at: https://ecommons.aku.edu/pakistan_fhs_mc_pathol_microbiol/718