1503. Use of Organism Identification by 16S Ribosomal RNA Polymerase Chain Reaction to Shorten Antimicrobial Length of Therapy
Session: Poster Abstract Session: Antimicrobial Stewardship: Role of Diagnostics
Saturday, October 10, 2015
Room: Poster Hall
  • 16S PCR Poster FINAL ID Week 2015.pdf (573.5 kB)
  • Background: 16S ribosomal RNA (rRNA) Polymerase Chain Reaction (PCR) and genetic sequencing can provide organism identification when traditional culture fails to identify clinically relevant organisms. The PCR test may positively identify an organism for potential treatment or return negative with no organism identified. If no organism is identified, the decision to deescalate or discontinue antibiotics may be made. The primary objective of this study was to assess the effect of a positive vs. negative 16S rRNA PCR on total length of antimicrobial therapy (LOT).

    Methods: Patients admitted to Northwestern Memorial Hospital between 10/2008 and 11/2014 that had a 16S rRNA PCR test performed on a sterile site (e.g. blood, cerebrospinal fluid), direct specimen (e.g. heart valve tissue) were considered for inclusion. All patients had a suspected active infection based on clinical presentation and/or consultation from the ID service. Patients with a 16S rRNA PCR (+) were matched 1:1 based on specimen site to patients with 16S rRNA PCR (-). Pertinent variables including site of suspected infection were collected.

    Results: In total, 90 patients were included (n=45 16S rRNA PCR (+) and (-)). The most common suspected infection was endocarditis (n=38), followed by osteomyelitis (n=13). Baseline demographics including modified APACHE II score did not differ between groups. Patients with a 16S rRNA PCR (-) had a shorter median total LOT than patients with a 16S rRNA PCR (+) (33 days [IQR 8-46] vs. 43 days [IQR 29-51], p=0.02). Antibiotics post-PCR were discontinued more frequently in patients with 16S rRNA PCR (-) than 16S rRNA PCR (+) (38% vs 4%, p<0.01). In a subgroup analysis of endocarditis, patients with 16S rRNA PCR (-) had a numerically shorter median LOT (32.5 [IQR 12.5-46] vs 45 [IQR 31-52], p=0.08) and had more frequent discontinuation of antimicrobials (37% vs 5%, p=0.04) than patients with16S rRNA (+).

    Conclusion: 16S rRNA PCR may be useful as a stewardship tool to decrease overall LOT and discontinue antibiotics in patients without detection of a microbial organism. Future studies are needed to further determine the potential use of 16S rRNA PCR as a diagnostic aid for difficult to culture microbes or sites.

    Filiz Yucebay, PharmD1, Elise Gilbert, PharmD1,2, Danielle Smith, PharmD3, John Esterly, PharmD1,2, Chao Qi, PhD1, Michael Malczynski, BS1, Michael Postelnick, RPh1 and Milena Mclaughlin, PharmD, MSc1,3, (1)Northwestern Memorial Hospital, Chicago, IL, (2)Chicago State University College of Pharmacy, Chicago, IL, (3)Midwestern University Chicago College of Pharmacy, Downers Grove, IL


    F. Yucebay, None

    E. Gilbert, None

    D. Smith, None

    J. Esterly, None

    C. Qi, None

    M. Malczynski, None

    M. Postelnick, None

    M. Mclaughlin, BioCryst Pharmaceuticals: Served on Advisory Board , Consulting fee

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 7th with the exception of research findings presented at the IDWeek press conferences.