Streptococcus pneumoniae can be differentiated from Viridans streptococci by various features:
| S.N. | Properties | Pneumococcus | Viridans streptococci |
| 1 | Morphology | Lanceolate or flame-shaped | Round/oval |
| 2 | Arrangement | Gram-positive cocci in pairs | Gram-positive cocci in long chains |
| 3 | Capsule | Present | Absent |
| 4 | On blood agar | Draughtsman or carom coin colony | Convex shaped colony |
| 5 | Liquid medium | Uniform turbidity | Granular turbidity |
| 6 | Bile solubility | Soluble in bile | Insoluble in bile |
| 7 | Inulin fermentation | Fermenter | Non-fermenter |
| 8 | Optochin | Sensitive | Resistant |
| 9 | Mice Pathogenicity | Pathogenic | Non-pathogenic |
| 10 | Quellung Test | Positive | Negative |
| 11 | Hemolysis | Alpha-hemolytic (under aerobic conditions) or Beta-hemolytic (under anaerobic conditions) | Alpha hemolytic or non-hemolytic |
| 12 | Pathogenesis | Causes pneumonia | Causes mainly oral infections |
References
- Apurba Sankar Sastry and Sandhya Bhat K. 2018. Review of Microbiology and Immunology. Sixth Edition. Jaypee Brothers Medical Publishers (P) Ltd.
- Suzuki N, Seki M, Nakano Y, Kiyoura Y, Maeno M, Yamashita Y. 2005. Discrimination of Streptococcus pneumoniae from viridans group streptococci by genomic subtractive hybridization. J Clin Microbiol. 43(9):4528–4534. doi:10.1128/JCM.43.9.4528-4534.2005.
- https://microbiologyinfo.com/difference-between-s-pneumoniae-and-viridans-streptococci/
- https://en.wikipedia.org/wiki/Viridans_streptococci
- https://en.wikipedia.org/wiki/Streptococcus_pneumoniae
- http://textbookofbacteriology.net/S.pneumoniae.html
- https://www.drbeen.com/blog/difference-streptococcus-pneumoniae-streptococcus-viridans/
