Gram – CSF : neutrophils – gram positive cocci


A simulated CSF smear collected from 54 year old alcoholic patient was sent to category A, B, C, and C1 laboratories.

Participants were expected to report the presence of neutrophils and gram positive cocci.


  1. Reporting the presence of neutrophils and gram positive cocci, with the additional morphological description of diplococci /lancet shaped is strongly suggestive that S. pneumoniae is the likely pathogen in this patient with meningitis. This information is valuable to the physician treating the patient, supporting the choices for the standard empiric antibiotic therapy according to guidelines and lessening concerns about need for prophylaxis of close contacts which need to be considered in the case of Neis-seria meningitidis meningitis.
  2. A caution to keep in mind is that Listeria, despite being gram pos-itive bacilli, can sometimes look more coccoid on primary gram stain, and in patients who may be at risk for Listeria meningitis this should be considered, since the standard empiric antibiotic choices are not active against Listeria.

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