Diagnosis of ventricular drainage-related bacterial meningitis by broad-range real-time polymerase chain reaction.

OBJECTIVE

To compare a broad-range real-time polymerase chain reaction (PCR) diagnostic strategy with culture to evaluate additional effects on the etiological diagnosis and the quantification of the bacterial load during the course of ventricular drainage-related bacterial meningitis (VR-BM).

METHODS

We applied a PCR that targeted conserved regions of the 16S ribosomal ribonucleic acid gene to cerebrospinal fluid (CSF) samples from patients with external ventricular drainage or a ventriculoperitoneal shunt during the course of VR-BM. We compared the PCR results with CSF cultures. A total of 350 routine CSF samples were consecutively collected from 86 patients. The CSF deoxyribonucleic acid was automatically purified and subjected to PCR. Amplicons from the PCR samples that were positive for VR-BM were subsequently deoxyribonucleic acid sequenced for final identification. Clinical data were extracted from patient files.

RESULTS

Sixteen patients had at least one VR-BM-positive sample as diagnosed from culture or PCR. Nineteen episodes were diagnosed with signs of VR-BM (n = 16 patients) or were determined to be contaminated (n = 3 patients). Four episodes of VR-BM were diagnosed via PCR alone and were predominantly caused by gram-negative pathogens, five episodes were diagnosed via culture alone, and seven episodes were diagnosed via both culture and PCR. Five patients had mixed infections. Overall, 71 samples were positive for VR-BM as indicated by either one or both of the methods. Eighteen CSF samples were VR-BM positive as indicated by culture alone, and 21 CSF samples were positive as indicated via PCR alone.

CONCLUSIONS

Culture supplemented with broad-range, real-time PCR may increase the number of etiologically diagnosed VR-BM episodes, particularly when these are caused by gram-negative bacteria.