Detection of meningococcal meningitis in cerebrospinal fluid of patients with neurological disorders in government hospitals of Karachi.

OBJECTIVE: To investigate the microbiological yield from the apparently transparent cerebrospinal fluid samples of in-patients with suspected neurological disorders.
METHODS: Samples of CSF were collected from Neurology and Neurosurgery Wards of the Jinnah Postgraduate Medical Centre and the Civil Hospital, Karachi, from December 2007 to March 2012, and comprised cerebrospinal fluid samples collected from neurologically compromised patients through lumbar puncture. The processing of the samples was done at the Department of Microbiology, University of Karachi. Moreover, 10ml of each sample was streaked separately on different culture media, i.e. Nutrient Agar, Blood Agar and Chocolate Agar, for the isolation of both aerobic and anaerobic bacteria.
RESULTS: Of the 92 samples, bacterial meningitis was found in 21(22.8%), whereas 71(77.1%) samples did not yield any bacterial aetiology. Besides, 1(4.7%) sample revealed Gram-positive rods of L. monocytogenes while Gram-negative kidney-shaped N. meningitidis was found in 20(95.24%) samples.
CONCLUSIONS: Present study highlighted that apparently clear CSF samples predominantly revealed meningococcal meningitis. It is important to note that extracellular bacterial growth in CSF is not always the primary goal of pathogenesis, therefore establishing a fact that turbidity of CSF is not the cardinal symptom for the diagnosis of bacterial meningitis.