Outbreak of highly resistant A. baumannii in Wisconsin care facilities: an in-depth genetic characterization


Kelsey Florek, MPH, PhD
2019 AMD 2-Day
September 23, 2019


Slides live from:
www.k-florek.net/talks

Overview


  • Inital Case
  • Outbreak Investigation
  • Genetic Characterization

September 2018

  • Patient at facility A with a lower respiratory infection 3 months after a heart transplant
  • Respiratory cultures revealed a carbapenem resistant A. baumannii
  • Treatment:
    • Polymixin-B
    • Meropenem
    • Colistin
    • Cefiderocol as compassionate treatment
  • Patient passed away, unclear if cause was sepsis
  • 5 additional patients from Facility A had sputum cultures that were positive for carbapenem resistant A. baumannii
  • Wisconsin State Laboratory of Hygiene

Determining relatedness

Antimicrobial susceptibility

  • Amikacin: Resistant
  • Aztreonam: Resistant
  • Cefepime: Resistant
  • Cefotaxime: Resistant
  • Ceftazidime: Resistant
  • Ciprofloxacin: Resistant
  • Colistin: Susceptible
  • Doripenem: Resistant
  • Doxycycline: Resistant
  • Gentamicin: Resistant
  • Imipenem: Resistant
  • Levofloxacin: Resistant
  • Meropenem: Resistant
  • Minocycline: Intermediate
  • Piperacillin-tazobactam: Resistant
  • Polymyxin-B: Susceptible
  • Ticarcillin-clavulanate: Resistant
  • Tobramycin: Resistant
  • Trimethoprim-sulfamethoxazole: Resistant

Outbreak isolates are OXA-72

Case Definitions

  • Probable

    • Carbapenem resistant A. baumannii clinical isolate with outbreak AST profile

  • Confirmed

    • Carbapenem resistant A. baumannii clinical isolate genetically clustering with other outbreak isolates and harboring the OXA-24/40-like β-lactamase OXA-72

Case Definitions

  • Probable (n=43)

    • Carbapenem resistant A. baumannii clinical isolate with outbreak AST profile

  • Confirmed (n=22)

    • Carbapenem resistant A. baumannii clinical isolate genetically clustering with other outbreak isolates and harboring the OXA-24/40-like β-lactamase OXA-72

OXA-72 isolates cluster together

OXA-72 isolates cluster together

OXA-72 plasmid

Povilonis et al. (2013) J Antimicrob Chemother

10 Second Synopsis

  • Highly resistant A. baumannii's are a real threat
  • Sequencing was the only way to distinguish relatedness and OXA mechanism
  • Long reads useful in resolving mechanism location and transferability

Acknowledgements

HTML Presentation Framework
  • Wisconsin State Laboratory of Hygiene
    • Abigail Shockey
    • Allen Bateman
    • Sara Wagner
  • Wisconsin Department of Public Health
    • Megan Lasure
    • Lina Elbadawi
  • Froedtert and The Medical College of Wisconsin
    • L Silvia Munoz-Price

special thanks to:

  • Office of Molecular Detection