Recent Serotypes
As of updates in January 2025, there have been 107 serotypes identified
Vaccines
Licensed
In Development
Multilocus Sequence Typing
Multilocus sequence typing is the process for characterizing isolates of bacteria using the sequences of internal gene fragments from several established house-keeping genes.
Below is a small sampling of MLST as currently more than 1 million have been identified. Learn more from PubMLST.
Clonal Complexes
Clonal complexes describe clusters of serotypes that share similarities in their sequence types. Serotypes within the same clonal complex may exhibit similar characteristics or traits that may aid in understanding their transmission and virulence.
Global Pneumococcal Sequence Cluster
A Global Pneumococcal Sequence Cluster (GPSC) is an “international genomic definition of a pneumococcal lineage” which captures the variation across the entire genome. Learn more from the Global Pneumococcal Sequencing Project
History
## Warning: package 'cronologia' was built under R version 4.4.21881
First discovered independently isolated by Louis Pasteur (deemed 'microbe septicemique de salive') in France from the saliva of a rabies patient as well as by George M. Sternberg in the U.S., who named it 'Micrococcus pasteuri' (Reference 52)
1886
Renamed 'pneumococcus' for its close association with pneumonia (Reference 52)
1911
Start of efforts to develop an effective pneumococcal vaccine (Reference 53)
1920
Renamed as 'Diplococcus pneumoniae' since it was typically observed in pairs (Reference 52)
1928
Transformation of life demonstrated by Frederick Griffith demonstrated by turning harmless pneumococcus into a lethal form through the co-inoculation of live pneumococci into a mouse with heat-killed virulent pneumococci; this experiment played a vital role in identifying DNA as genetic material (Reference 52)
1929
The first 32 serotypes were described by Georgia Cooper (Reference 27)
1939
Danish Prince Valdemar dies of pneumonia and his failed treatment of serogroup 9 antisera revealed additional diversity in serogroup 9, allowing for the identification of serotype 9V (Reference 53)
1960s
Start of efforts to develop a polyvalent pneumococcal vaccine (Reference 53)
1974
Renamed 'Streptococcus pneumoniae' for its similarities in chain formation similar to other Streptococcus spp. (Reference 52)
1977
First pneumococcal polysaccharide vaccine licensed in U.S., contained which antigens from 14 serotypes of pneumococci (Reference 53)
1983
The 23-valent polysaccharide vaccine was licensed (PPSV23), replacing the 14-valent (Reference 53)
2000
First conjugate pneumococcal vaccine licensed in U.S., covering 7 serotypes (PCV7) (Reference 53)
2010
Introduction of 13-valent pneumococcal conjugate vaccine (PCV13), covering six serotypes in addition to PCV7 (Reference 53)
2020
The 100th serotype, 10D, is identified (Reference 7)
More Resources
Additional reference tools on Streptococcus pneumoniae may be found at:
References
About Us
This reference tool was created by Chessley B. Blacklock, Daniel M. Weinberger, Stephanie Perniciaro, and Anne L. Wyllie at the Yale School of Public Health. This tool was last updated in January 2025.
We recommend using the following citation (APA):
Blacklock, C. B., Weinberger, D. M., Perniciaro, S., & Wyllie, A. L. (2024). Streptococcus pneumoniae serotypes. https://pneumococcalcapsules.github.io/serotypes/
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