PowerPoint Contents
Streptococcus pneumoniae (Enlarged view)Slide 1. Streptococcus pneumoniae meningitis
This cerebrospinal fluid from a child with meningitis contains many neutrophils and oval gram-positive cocci singly and in pairs. Because the number of organisms in infected cerebrospinal fluid is small, most laboratories centrifuge the specimen to increase the concentration and then use the sediment for both stains and cultures. The density of microbes per milliliter of fluid cannot be estimated from a specimen that has been centrifuged.
Neisseria meningitidis (Enlarged view)
Slide 2. Neisseria meningitidis meningitis
This cerebrospinal fluid contains a high concentration of neutrophils and many gram-negative diplococci singly and in pairs. Although Neisseria meningitidis is the most likely organism, differentiation from N. gonorrhoeae, which can also cause meningitis, is not possible with Gram stain.
Haemophilus influenzae (Enlarged view)
Slide 3. Haemophilus influenzae meningitis
This cerebrospinal fluid contains many neutrophils and gram-negative coccobacilli, primarily in the cytoplasm of the white cells.
Listeria monocytogenes Enlarged view
Slide 4. Listeria monocytogenes meningitis
This cerebrospinal fluid contains a few neutrophils and two slender gram-positive bacilli. Although Gram stains of cerebrospinal fluid are positive in specimens from about 80% of all patients with bacterial meningitis, organisms are detected in the cerebrospinal fluid of only about 40% of patients with Listeria meningitis. Even when specimens reveal bacteria, only a small number may be visible.
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