Cerebrospinal fluid Culture & Body Fluid Culture

Indications Mainly in Suspected cases of meningitis. See video

Aim of the test Diagnosis of the bacteria or fungal meningitis by microscopic examination and culture with identification and susceptibility test of the isolated organism. commensals

Specimen collection Explain procedure to the patient and obtain written consent. See video

Quantity of specimen 3 ml of CSF is sufficient for culture. Time relapse before processing the sample CSF is an emergency specimen and should be processed immediately. Storage: Room temperature The sample is submitted in 3 tubes: chemistry, microscopic, culture sensitivity.

Specimen processing Media Two Blood Agar Chocolate Agar MacConkey Agar Fluid Thioglycollate

Culturing procedure As a general rule in CSF and body fluid specimens for culture Centrifuge clear specimen and inoculate plates and do staining from sediments. Turbid specimens may not be centrifuged.

Result reporting Results of the microscopy and all positive cultures of CSF are reported immediately to the treating physician. Negative bacterial results are sent out 72 hours after the CSF is received. Examine all plates and broth medium for growth after 24 hrs. If no visible growth reincubate. Check all plate daily and discard after 7 days especially if gram stain was + Generally +ve culture indicate pathogens

Turn around time Gram stain result is reported within 30 minutes of specimen receipt Positive Culture results = 3- 5 days Negative Culture results = 2-3 day

Additional information Several antigen detection methods are available for capsular antigen of H. influenzae, N. meningitidis, S. pneumoniae and Group B streptococci in CSF which showed specificity and sensitivity of about 90-97%. The routine culture for CSF does not include all organisms mentioned in the above table.

Viral we test mainly: HSV and Enterovirus Finding bacteria does not necessarily mean the infection is contagious, unless it is meningococcal meningitis Viral we test mainly: HSV and Enterovirus Fungal we test for Candida and Cryptococcus. Herpes simplex virus

Body Fluid Culture

Body Fluid Culture This means Culture of Body Fluid such as peritoneal, pericardial, plural, ascitic, synovial. Aim of the test Isolate and identify pathogenic organisms from normally sterile body fluids and perform sensitivity test. Types of specimen Aseptically aspirated body fluid (e.g., synovial, peritoneal fluid, pericardial fluid, and pleural fluid ).

Patient preparing Explain procedure to the patient and obtain written consent. Swab skin over the site of puncture with 2% tincture of iodine in concentric circles. Iodine should remain in contact with skin for at least 1 minute prior to puncture to ensure complete antisepsis. Before puncture, 70% alcohol is used to remove iodine from skin.

Specimen collection Contamination with normal microbiota from skin, rectum, vaginal tract, or other body surfaces should be avoided. Indicate the specific source and pertinent clinical history on the request form. See video

Quantity of specimen: 1-5 mL is adequate. Time relapse before processing the sample Body fluids should be treated as CSF specimens and should processed immediately. Storage Maintain specimen at room temperature. Do not refrigerate. Media Blood Agar (2 plates) Chocolate Agar, MacConkey Agar Thioglycollate broth

Specimen processing

Result reporting Report Gram stain finding as an initial report. Report the isolated pathogen and its sensitivity pattern as a final report. Turn around time: Gram stain and wet mount results should be available 1 hour after specimen receipt. Isolation of a possible pathogen can be expected after 2-3 days. Negative culture will be reported out 1-2 days after the receipt of the specimen.