Differences Between Streptococcus Pneumoniae and Viridans Streptococci

S.N   Streptococcus pneumoniae S.N   Viridans streptococci
1. Are capsulated. 1. Are non-capsulated.
2. Shape is lanceolate or flame shaped. 2. Shape is oval or round cells.
3. Give Positive quellung test. 3. Give negative quellung test.
4. On blood agar, dome-shaped initially, later on appear as draughtsman colonies. 4. On blood agar, dome-shaped.
5. Shows growth as uniform turbidity in liquid media. 5. Shows growth as granular turbidity, powdery deposit.
6. Positive bile solubility test. 6. Negative bile solubility test.
7. Positive inulin fermentation test. 7. Negative inulin fermentation test.
8. Sensitive towards optochin test. 8. No sensitive or resistant towards optochin test.
9. Fatal infection in intra-peritoneal inoculation. 9. Non-pathogenic in intra-peritoneal inoculation.
10. Responsible for causing pneumonia. 10. Responsible for causing several oral infections.
11. Alpha and beta hemolysis. 11. Alpha or non-hemolytic.
12. Gram positive and arranged in pairs. 12. Gram positive but arranged in chains.
13. Appear as a single species. 13. Appear as a large group of species.

Pneumococcus vs Viridans streptococci- 12 Major Differences

Image source: microbenotes


i) https://microbenotes.com/differences-between-pneumococcus-and-viridans-streptococci/

ii) https://microbiologynote.com/differences-between-pneumococcus-and-viridans-streptococci/

iii) https://microbiologyinfo.com/difference-between-s-pneumoniae-and-viridans-streptococci/

Differences between Streptococcus pneumoniae and Viridans streptococci