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Author Notes:

Correspondence and requests for materials should be addressed to F.C.L. (email: flessa@cdc.gov) or B.B. (email: bbeall@cdc.gov)

Author Contributions: F.C.L., N.G.R., M.M.F., G.R., M.G.C., B.B., C.G.W. contributed with the design of the study. F.C.L. and J.M. were responsible for training of study staff on data and specimen collection per protocol, and overall oversight and monitoring of study activities.

N.G.R., N.M.B., K.T., L.H.H., M.M.F., J.W. implemented and oversaw the study activities at the study sites.

F.P. and M.G.C. were responsible for processing all upper respiratory samples and for the isolation of S. mitis strains.

R.G. performed the immunodiffusion assays and was responsible for the preparation of anti-Streptococcus mitis sera from rabbits.

G.R. conducted and interpreted the opsonophagocytosis killing tests. B.B. was responsible for phylogenetic and whole genome sequence analyses and interpretation, and oversight of laboratory activities related to this study.

All authors reviewed epidemiologic and laboratory results and provided input prior to manuscript development.

F.C.L., B.B., C.G.W. were responsible for the initial draft of the manuscript.

However, all authors critically reviewed and edited the manuscript.

Acknowledgements The authors want to acknowledge the following personnel for their help with participant recruitment, specimen collection, questionnaire administration and vaccination follow-up: Amy Tunali and Stephanie Thomas from the Georgia Emerging Infections Program and Emory University School of Medicine; Mary Bower, Regina Mosley, Emily Presmanes, Sabrina Williams, and Nina McNair from Emory University; Anna Sharova, Jackie Langdon, and Rosemary Hollick from Johns Hopkins; Diane Kober, Gary Hollick and Christina Felsen from the University of Rochester School of Medicine and Dentistry; Lura McKnight and Gail Hughett from Vanderbilt Medical Center.

We also acknowledge the following individuals from the CDC’s Streptococcus and Microbial Pathogenesis and Immune Response Laboratories: Iaci Moura, Shanda Larson and Anne-Kathryn Venero for providing technical support for culture and PCR testing; Sopio Chochua, Theresa Tran, and Hollis Walker for providing the S. mitis genomic sequences, Yuan Li for his interpretation of the potential ancestry of the cps1 loci, and Ellie Kim for providing technical support on the OPK assays.

Finally, we are very grateful to Rex Howard and Will Thomas for their expert guidance with antisera preparation.

Competing Interests: Dr. Lee Harrison has served on a scientific advisory board for GlaxoSmithKline, and has been a speaker at a Merck scientific symposium.

However, none of these commitments had an influence on the design and interpretation of the data.

All other authors report no competing financial or non-financial interests related to the work described.


Research Funding:

This work was funded by the Emerging Infections Program (EIP) Cooperative Agreement between the four EIP sites and the Centers for Disease Control and Prevention (Grant# CDC-RFA-CK17-1701).


  • Science & Technology
  • Multidisciplinary Sciences
  • Science & Technology - Other Topics
  • LYTA

Streptococcus mitis Expressing Pneumococcal Serotype 1 Capsule

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Journal Title:

Scientific Reports


Volume 8, Number 1


, Pages 17959-17959

Type of Work:

Article | Final Publisher PDF


Streptococcus pneumoniae’s polysaccharide capsule is an important virulence factor; vaccine-induced immunity to specific capsular polysaccharide effectively prevents disease. Serotype 1 S. pneumoniae is rarely found in healthy persons, but is highly invasive and a common cause of meningitis outbreaks and invasive disease outside of the United States. Here we show that genes for polysaccharide capsule similar to those expressed by pneumococci were commonly detected by polymerase chain reaction among upper respiratory tract samples from older US adults not carrying pneumococci. Serotype 1-specific genes were predominantly detected. In five oropharyngeal samples tested, serotype 1 gene belonging to S. mitis expressed capsules immunologically indistinct from pneumococcal capsules. Whole genome sequencing revealed three distinct S. mitis clones, each representing a cps1 operon highly similar to the pneumococcal cps1 reference operon. These findings raise important questions about the contribution of commensal streptococci to natural immunity against pneumococci, a leading cause of mortality worldwide.

Copyright information:

© 2018, The Author(s).

This is an Open Access work distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).
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