1. Streptococci Basmah almaarik
Lecture # 5b

2. Streptococci
All are Gram Positive Cocci arranged in chains (short or long)
All are Catalase -ve
+ ve
- ve

3. Gram Stain
Staphylococci
streptococci

4. Culture Fastidious organism  no growth on NA Grows well on BAP
Facultative anaerobe
Grow at 37C need 24 to 48 hour .

5. Streptococcus Classification
Alpha hemolytic
S. viridans
S. pneumoniae
Beta hemolytic:
Group A, B, C, G & D
Lancefield grouping according to antigens in their cell wall
Non-hemolytic:
Enterococcus (formally known as Group D)

6. Alpha Hemolytic Streptococci
Give alpha hemolysis on BAP.
It Can be divided in to 2:
Viridans group
S.pneumoniae

7. Streptococcus viridans
s. pneumoniae
Streptococcus viridans

8. Viridans Streptococci
S. PNEUMONIAE
Alpha haemolysis
Pin point colonies
Optochin  resistant
Bile Solubility  -ve
Part of normal flora of upper respiratory and GI
Alpha haemolysis
Ring form colonies
Tanslucent or mucoid
Optochin  sensitive
Sile solubility  +ve
Not part of NF
Not Capsulated
Flattened with raised edges
Capsulated

9. Viridans Streptococci
S. PNEUMONIAE
GPS in chains
GPC elongated (Lanceolated) diplococci

10. On the primary culture of isolation plate before incubation
1. Optochin Test
Ethylhydrocupreine hydrochloride.
Zone of inhibition of 14 mm or more  sensitive  S. pneumoniae
No zone of inhibition  S.viridans
Always don on a BAP.
On the primary culture of isolation plate before incubation

11. Optochin Disk

12. . Bile Solubility Test
To test if colonies are lysed by bile salt (such as desoxycholate) or not.
There are 2 ways to do the test :
In a tube
On plate

13. Bile Solubility in Tube
2 ml of saline in a tube
Emulsify several colonies of test organism in it
Divide organism suspension in 2 tubes
Add 2 drops of bile salt to one tube and 2 drops of sterile distilled water to the other.
Leave mn at RT

14. Bile Solubility on Plate
Add drop of bile salt to specified part of plate
Incubate at 37C for min
Colony disappear  +ve
Colony stay  -ve

17. Rapid Detection of S. pneumoniae
Rapid latex and coagglutination tests are available to detect capsular pneumococcal antigen in CSF or other sterile body fluids.

18. Sensitivity Testing of S. pneumoniae

19. Thank You

20. Your work today:
Do gram stain for S.viridance and S.pnemoniae (show it to the instructor)
Streak blood agar with S.viridance and S.pnemoniae and inoculate both organisms with Optochin disk.