- Aerobic, Gram-positive diplococcus [Fig 1] with a capsule.
- Grows on blood agar.
- Capsular swelling w/ application of Quelling antisera [Fig 2].
- Serotypes: immunity is serotype-specific.
- Abx resistance is often serotype-specific.
- Serotypes 19A and 19F have emerged as predominant pathogens following increased immunization.
- Minimum inhibitory concentration (MIC) to penicillin (mcg/mL) breakpoints for non-CNS specimens.
- Susceptible: 2 mcg/mL
- Intermediate: 4 mcg/mL
- Resistant: 8 mcg/mL
- Previously were determined solely based on possible meningeal disease.
- The breakpoints above are based on anticipated respiratory or non-CNS isolates.
- The susceptible breakpoint for meningitis caused by S. pneumoniae remains unchanged.
- S= 0.06 mcg/mL
- I = 0.12 - 1.0 mcg/mL
- R ≥ 2 mcg/mL
- This means that >95% of strains are sensitive to penicillin, the preferred drug.
- Penicillin resistance is increasing due to "replacement strains" associated with the extensive use of conjugated pneumococcal vaccines, although now PCV-15 and PCV-20 are on the scene. These replacement serotypes are relatively nonsusceptible to penicillin.
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Last updated: December 11, 2022
Auwaerter, Paul G. "Streptococcus Pneumoniae." Johns Hopkins ABX Guide, The Johns Hopkins University, 2022. Johns Hopkins Guides, www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX_Guide/540523/all/Streptococcus_pneumoniae.
Auwaerter PG. Streptococcus pneumoniae. Johns Hopkins ABX Guide. The Johns Hopkins University; 2022. https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX_Guide/540523/all/Streptococcus_pneumoniae. Accessed June 8, 2023.
Auwaerter, P. G. (2022). Streptococcus pneumoniae. In Johns Hopkins ABX Guide. The Johns Hopkins University. https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX_Guide/540523/all/Streptococcus_pneumoniae
Auwaerter PG. Streptococcus Pneumoniae [Internet]. In: Johns Hopkins ABX Guide. The Johns Hopkins University; 2022. [cited 2023 June 08]. Available from: https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX_Guide/540523/all/Streptococcus_pneumoniae.
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TY - ELEC T1 - Streptococcus pneumoniae ID - 540523 A1 - Auwaerter,Paul,M.D. Y1 - 2022/12/11/ BT - Johns Hopkins ABX Guide UR - https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX_Guide/540523/all/Streptococcus_pneumoniae PB - The Johns Hopkins University DB - Johns Hopkins Guides DP - Unbound Medicine ER -