Streptococcus Pneumonia
Which of the following is a characteristic feature on culture of Streptococcus pneumoniae organism?
| A |
Alpha-hemolytic colonies inhibited by optochin on blood agar and lysed by bile |
|
| B |
Beta-hemolytic colonies that are bacitracin-resistant on blood agar |
|
| C |
Beta-hemolytic colonies that are inhibited by bacitracin on blood agar |
|
| D |
Catalase-negative organisms that hydrolyze esculin in 40% bile and 6.5% NaCI |
Which of the following is a characteristic feature on culture of Streptococcus pneumoniae organism?
| A |
Alpha-hemolytic colonies inhibited by optochin on blood agar and lysed by bile |
|
| B |
Beta-hemolytic colonies that are bacitracin-resistant on blood agar |
|
| C |
Beta-hemolytic colonies that are inhibited by bacitracin on blood agar |
|
| D |
Catalase-negative organisms that hydrolyze esculin in 40% bile and 6.5% NaCI |
These findings are used to identify Streptococcus pneumoniae. Optochin sensitivity is used to differentiate the viridans streptococci (resistant) from S. pneumoniae (sensitive). Another test used to identify S. pneumoniae is the Quellung reaction. The only medically important optochin-sensitive organism that gives a positive Quellung reaction is S. pneumoniae.
- Beta-hemolytic colonies that are bacitracin-resistant on blood agar is seen with Streptococcus agalactiae.
- Beta-hemolytic colonies that are inhibited by bacitracin on blood agar is seen with Streptococcus pyogenes.
- Catalase-negative organisms that hydrolyze esculin in 40% bile and 6.5% NaCI is seen with Enterococcus faecalis.
A child has a history of recurrent infections with organisms having polysaccharide antigens (i.e., Streptococcus pneumoniae and Haemophilus influenzae). This susceptibility can be explained by a deficiency of ?
| A |
C3 nephritic factor |
|
| B |
C5 |
|
| C |
IgG subclass 2 |
|
| D |
Myeloperoxidase in phagocytic cells |
A child has a history of recurrent infections with organisms having polysaccharide antigens (i.e., Streptococcus pneumoniae and Haemophilus influenzae). This susceptibility can be explained by a deficiency of ?
| A |
C3 nephritic factor |
|
| B |
C5 |
|
| C |
IgG subclass 2 |
|
| D |
Myeloperoxidase in phagocytic cells |
IgG is the predominant antibody in the secondary immune response. IgG subclass 2 is directed against polysaccharide antigens and is involved in the host defense against encapsulated bacteria.
Which is the commonest Post splenectomy infection‑
| A |
Streptococcus pyogenes |
|
| B |
Staphylococcus aureus |
|
| C |
Streptococcus Pneumoniae |
|
| D |
Pseudomonas aeruginosa |
Which is the commonest Post splenectomy infection‑
| A |
Streptococcus pyogenes |
|
| B |
Staphylococcus aureus |
|
| C |
Streptococcus Pneumoniae |
|
| D |
Pseudomonas aeruginosa |
Ans is c ie. Streptococcus
Streptococcus pneumoniae is the most common inf. in post splenectomy patient.
• Schwartz 9/e writes -“The most common causal organism, accounting for as many as 50 to 90% of all OPSI
• cases, remains pneumococcus. Meningococcus, H. influenzae type B, and group A streptococci follow in order of frequency.”
Quellung reaction is seen in ‑
| A |
Group B streptococcus |
|
| B |
Staphylococcus |
|
| C |
Pneumococcus |
|
| D |
Enterococcus |
Quellung reaction is seen in ‑
| A |
Group B streptococcus |
|
| B |
Staphylococcus |
|
| C |
Pneumococcus |
|
| D |
Enterococcus |
Ans. is ‘c’ i.e., Pneumococcus
A suspension of pneumococci is mixed on a slide with a drop of the type specific antiserum and methylene blue. On the presence of homologous antiserum capsule becomes apparently swollen, sharply delineated and refractile. o This is called Quellung reaction.
Streptococcus pneumonia produces which type of hemolysis ‑
| A |
Alpha |
|
| B |
Beta |
|
| C |
Gamma |
|
| D |
Any of the above |
Streptococcus pneumonia produces which type of hemolysis ‑
| A |
Alpha |
|
| B |
Beta |
|
| C |
Gamma |
|
| D |
Any of the above |
Ans. is ‘a’ i.e., Alpha
