Processing of Cerebrospinal Fluid for Diagnosis of Community Acquired Bacterial Meningitis

• Process as soon as received.

Macroscopic finding:

• Volume of CSF

• Gross appearance (clear, cloudy, bloody)

Media:
Chocolate agar                                    37oC+5% CO2- 24-48 hrs
Sheep blood agar                                37oC+5% CO2- 24-48 hrs
Brain heart infusion (BHI) broth         370C-24-48 hrs
Inoculation of Media:

• Using a sterile pipette, aspirate fluid from bottom of the collection tube.

• Place 2-3 drops on each media. Streak in quadrants.

Smear Preparation:
If volume 1 ml then cytospin for smear preparation
Volume required: 0.5ml
Duration: 10min
Speed: 2000 rpm

If volume less than 1 ml: First inoculate media and broth then make smear. Put 2-3 drops of CSF on slide. Allow the drops to form large drop. Do not spread the drop.

If no cytospin available: Centrifuge CSF at 1800g for 15 minutes and made slides from sediment.
Stain the slides with gram stain.

Reference:
Manual of Clinical Microbiology Procedure Handbook, 2th Ed. 2004, ASM, Mary.K.York