2399. Beta-Lactam Therapy for Potential AmpC-Producing Organisms: A Cohort Study and an Updated Systematic Review and Meta-analysis
Session: Poster Abstract Session: Treatment of AMR Infections
Saturday, October 6, 2018
Room: S Poster Hall
  • ampC_producing_poster_IDweek_MC_RSL_REFS_done_20180926_updated.pdf (1.5 MB)
  • Background: Certain organisms, including Serratia, Providentia, Acinetobacter, Citrobacter, Enterobacter, and Morganella species (SPACE-M) may possess an inducible broad-spectrum beta-lactamase, AmpC, which is not inhibited by most beta-lactamase inhibitors. Our objective was to determine whether treating SPACE-M bloodstream infections (BSI) with potentially hydrolysable beta-lactams was associated with increased risk of 30-day mortality.

    Methods: A retrospective cohort study was performed including all adult cases of bacteremia attributed to SPACE-M species between April 2010 and June 2015 at the McGill University Health Centre (Montreal, Canada). We used multivariable logistic regression to estimate the odds ratio (OR) of death or recurrence within 30 days for potentially hydrolysable beta-lactams versus other therapies. We then updated a systematic review and meta-analysis comparing carbapenems to beta-lactam/beta-lactamase inhibitors (BL/BLIs). We included studies published up to December 31st, 2017 and calculated the unadjusted OR for mortality within 30 days comparing BL/BLI versus carbapenems as definitive therapy.

    Results: Over the five-year period, there were 173 BSI involving SPACE-M organisms at our center. After adjusting for patient comorbidities and severity of the initial illness, the use of hydrolysable beta-lactams as definitive therapy was not associated with an increased risk of death or recurrence when compared to other antimicrobial agents (OR 1.20, 95%CI 0.40 - 3.62). The meta-analysis further suggested that patients treated with BL/BLI therapy have similar outcomes to those treated with carbapenems (30-day mortality OR 1.13, 95%CI 0.58 – 2.20).

    Conclusion: The use of beta-lactam/beta-lactamase inhibitors may remain a viable carbapenem-sparing option for patients with potential AmpC-producing organisms.

    Matthew P. Cheng, MD1, Robyn Lee, PhD2, Alexandre P. Cheng, BSc3, Samuel De L'Étoile-Morel, MD4, Koray Demir, MDCM Candidate5, Cedric Yansouni, MD6, Patrick Harris, MBBS FRACP FRCPA7, Emily Mcdonald, MDCM, MSc8 and Todd C. Lee, MD, MPH8, (1)Harvard Medical School, Boston, MA, (2)Harvard School of Public Health, Boston, MA, (3)École Polytechnique de Montréal, Montréal, QC, Canada, (4)McGill University, Montreal, QC, Canada, (5)McGill University Faculty of Medicine, Montreal, QC, Canada, (6)Infectious Diseases, McGill University, Montreal, QC, Canada, (7)Central Pathology, Pathology Queensland, Brisbane, Australia, (8)Clinical Practice Assessment Unit, McGill University, Montréal, QC, Canada


    M. P. Cheng, None

    R. Lee, None

    A. P. Cheng, None

    S. De L'Étoile-Morel, None

    K. Demir, None

    C. Yansouni, None

    P. Harris, None

    E. Mcdonald, None

    T. C. Lee, None

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 3rd with the exception of research findings presented at the IDWeek press conferences.