OSPE Streptococcus pneumoniae- bacterial meningitis

Question 1

Specimens

Answer 1

1. CSF
   in pyogenic meningitis
   P:>180-increase
   Leucocytes:100-10000
   cell=neutrophil
   protein:> 250 increase
   glucose:<40 decrease
2. Blood culture

Question 2

CSF transport

Answer 2

▪ Should never be refrigerated
▪ If delay is expected – Kept in an incubator at 37°C

Question 3

case

Answer 3

-high grade fever, headache and vomiting.
-neck rigidity and Kernig’s sign was positive.
-CSF was sent for Gram stain and culture.

Question 4

Gram-stain

Answer 4

• pus cells seen
• Both intracellular and extracellular GP diplococci seen
• lanceolate (flame shaped)
• capsulated: unstained halo around each pair
• Presumptive diagnosis: Pneumococcal meningitis

Question 5

Blood agar

Answer 5

-After overnight incubation
Small colonies (0.5 – 1.0 mm) Dome shaped ; α hemolytic

-On prolonged incubation (48 hours)
▪ Draughtsman (Carrom coin) appearance
▪ Due to activation of autolytic amidase

Question 6

if choose 1 medium for meningitis?

Answer 6

Chocolate agar

Question 7

Chocolate agar

Answer 7

• Bleaching effect

Question 8

MacConkey agar

Answer 8

No growth

Question 9

biochemical test/Identification of the isolates

Answer 9

• Catalase – Negative
• Oxidase – Negative

Differentiation from viridans streptococci cuz both are alpha haemolytic:
1) Optochin sensitivity test: Sensitive
2) Bile solubility test: Positive(clear)
3)Inulin fermentation test: Positive

Question 10

Serotyping

Answer 10

-Quellung Réaction
-Latex agglutination