The use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for rapid bacterial identification in patients with smear-positive bacterial meningitis. (February 2018)

• Record Type: Journal Article
• Authors: Bishop, B.; Geffen, Y.; Plaut, A.; Kassis, O.; Bitterman, R.; Paul, M.; Neuberger, A.
• Is Part Of: Clinical microbiology and infection. Volume 24:Number 2(2018)
• Page Start: 171
• Page End: 174
• Publication Date: 2018-02
• Subjects: Cerebral spinal fluid -- Diagnosis -- Gram-negative rods -- MALDI-TOF-MS -- Meningitis -- Postneurosurgical; Medical microbiology -- Periodicals; Diagnostic microbiology -- Periodicals; Communicable diseases -- Periodicals; Infection -- Periodicals; 616.01
• DOI: 10.1016/j.cmi.2017.05.014
• Languages: English
• ISSNs: 1198-743X

Abstract

Abstract: Objectives: To assess the potential of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) in rapid identification of bacteria from smear-positive cerebrospinal fluid (CSF) in a cohort of patients with meningitis. Methods: Single-centre observational study, including adults and children with community-acquired or postneurosurgical bacterial meningitis. Meningitis was defined using established criteria. Samples of CSF that had a positive CSF Gram stain were directly examined by MALDI-TOF-MS. Identification was considered accurate when identical to the CSF culture or PCR results (species and genus level). Laboratory workers performing the MALDI-TOF-MS and interpreting its results were blinded to the direct smear results, except for the fact that it was positive. MALDI-TOF-MS results were not conveyed to clinicians. Results: MALDI-TOF-MS was tested on 44 CSF samples; ten samples were obtained from patients with community-acquired meningitis, and 34 samples were from patients with postneurosurgical meningitis. The assay identified bacteria correctly in 17/21 of the samples with Gram-negative rods observed on the direct smear, all obtained from patients who had undergone neurosurgery, (sensitivity 81%, 95% CI 64.2%–97.7%). In the postneurosurgical group, Gram-positive cocci were identified correctly in only 1/11 (9.1%) of the samples, and Candida species were not identified in two samples. Among patients with community-acquired meningitis, the assay did not identify Streptococcus pneumoniae in eight of eight samples, Neisseria meningitidis in one sample (1/1), and Streptococcus agalactiae in one sample (1/1). Conclusions: We found MALDI-TOF-MS to be useful in the rapid identification of Gram-negative rods directly from smear-positive CSF samples, but not of Gram-positive bacteria.