Use of Bacterial 16S Rrna Gene Sequencing Can Aid in Identification of Neurosurgical Infections

Introduction: Bacterial 16S rRNA gene sequencing can aid in the identification of neurosurgical infections. The bacterial 16S rRNA gene includes both conserved regions and variable regions that can provide genus and species identification of bacteria through nucleic acid amplification. 16S testing can be performed on any blood, body fluid, or tissue sample. While gram stain and culture are the preferred diagnostic modality to identify infections, cultures may be negatively impacted by antimicrobial pre-treatment or fail to grow fastidious organisms. 16S rRNA gene sequencing provides clinicians with another diagnostic option to identify bacterial pathogens through sequencing.

Methods: The results of 332 16S rRNA gene sequences in patients with concern for central nervous system or neurosurgical infections at the University of Wisconsin Hospital and Clinics from the year 2012 through 2016 are described. Source sample, 16S result, and corresponding culture data are analyzed.

Results: 16S rRNA amplification identified bacterial genome in 54 of the 332 samples (16.2%). Source material of positive 16S tests include 35 samples of cerebral spinal fluid (64.8%), 6 abscess (11.1%), 5 bone (9.3%), 3 soft tissue (5.5%), 2 brain (3.7%), and 2 epidural/subdural fluid (3.7%), and 1 disc aspirate (1.8%). Identified bacteria include 29 gram positive bacteria (53.7%), 9 gram negative (16.6%), 5 anaerobes (9.3%), 4 bacteria identified without genus or species (7.4%), and 7 contaminants or non-pathogenic bacteria (13%). Corresponding gram stain and culture of the same sources yielded no diagnostic information in 43 of the 54 positive 16S samples (79.6%)

Conclusion : 16S rRNA gene sequencing can aid in diagnosis of central nervous and neurosurgical infections and are especially useful in situations where gram stain and culture are negative. Further topics for research include yield of 16S in various tissue specimens and their role in antimicrobial stewardship.