Methods: SP PCR was run on the CSF of all specimens which were culture-negative after 3 days. Patients were excluded from analysis if: CSF was “clotted”, CSF was sent only for non-infectious workup, or it was a ventriculoperitoneal shunt specimen. A validated bacterial meningitis score (BMS) and details from the hospital course were used to determine the likelihood that patients had culture negative pneumococcal meningitis.
Results: Of 1329 CSF samples evaluated, there were 7 PCR positive samples, 5 appearing to be true positive cases of culture-negative pneumococcal meningitis. Two were determined to be false positives based on laboratory findings and the patients’ clinical courses. In the PCR negative group, there were 100 patients with BMS≥2, one of which had SP bacteremia, but whose CSF studies were not consistent with meningitis. Another had gram-positive cocci in pairs on CSF gram stain but negative CSF culture. Meningitis in this patient was thought to be most likely secondary to Streptococcus agalactiae due to gram stain findings and patient’s age.
Conclusion: The use of SP CSF PCR was able to identify several cases of culture negative meningitis. This occurred, however, at the expense of 2 false positive tests (28% of the positives). While testing appears especially diagnostically useful in patients pre-treated with antibiotics, the low prevalence of true infection results in an important number of false positives, which limits the use of SP CSF PCR in universal screening. Ultimately, SP CSF PCR is an attractive diagnostic tool when applied to selected patient specimens.
B. Bagga, None
J. P. Devincenzo, None
A. Patel, None
D. Keegan, None
S. Passarello, None
G. Gaines, None
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