Multi-drug Resistant Organism Data

Carbapenems are a class of powerful antibiotics considered the last line of defense against bacteria resistant to other antibiotics (Multi-Drug Resistant Organisms – MDROs). These dashboards summarize reports of carbapenem-resistant Enterobacteriaceae (CRE) and other carbapenemase-producing organisms (CPO) since tracking began in 2012. CRE and CPO counts include any person diagnosed in Washington and Washington residents diagnosed out-of-state.

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MDRO Data - Mobile Friendly

What's Here

The data for these dashboards comes from samples submitted and tested through the Washington State Public Health Laboratory, as well as reports from other states made to the Healthcare Associated Infections (HAI) Program. These dashboards display data reported since 2012 and is updated quarterly.

How are cases counted?

Cases are counted using the 2018 CSTE case definition. A case is counted once for each genus/species/carbapenemase profile per patient every 365 days. Samples producing more than one carbapenemase are counted once for each type.

Carbapenemase Testing at the Public Health Laboratory

Carbapenem-resistant Enterobacteriacae (CRE)

As of May 2015, the definition a CRE case is:

E. coli, Klebsiella spp., and Enterobacter spp. resistant to any carbapenem, according to thresholds established in Clinical Laboratory Standards Institute M100-ED30:2020 Performance Standards for Antimicrobial Susceptibility Testing, 30th Edition.

Testing performed at the Public Health Laboratory (PHL) on CRE includes a bacterial identification and antibiotic sensitivity (AST) test, a phenotypic test to detect carbapenemase activity using the Modified Carbapenem Inactivation Method (mCIM), and polymerase chain reaction (PCR) test for the following five common carbapenemase genes:

  • Klebsiella pneumoniae carbapenemase (KPC)
  • New Delhi metallo-β-lactamase (NDM)
  • Oxacillin-hydrolyzing β-lactamase-48 (OXA-48)
  • Verona integron-encoded metallo-β-lactamase (VIM)
  • Imipenem-hydrolyzing β-lactamase (IMP)

Any sample that is positive by mCIM test but negative by PCR for the five carbapenemase genes is submitted to Centers for Disease Control and Prevention for further testing. PHL tests other carbapenem resistant (CR) genera within the family Enterobacteriaceae by special request and through voluntary sentinel surveillance agreements with laboratories.

Other Carbapenem-resistant Organisms

PHL also tracks carbapenemase production in other types of bacteria. There are 22 sentinel laboratories in Washington that submit CR-Pseudomonas, and DOH requests all laboratories in the state submit CR-Acinetobacter. PHL began testing CR-Acinetobacter with the following carbapenemase targets in March 2019:

  • Oxacillin-hydrolyzing β-lactamase-23 like (OXA-23)
  • Oxacillin-hydrolyzing β-lactamase-24/40 like (OXA-24/40)
  • Oxacillin-hydrolyzing β-lactamase-58 like (OXA-58)

Carbapenem-resistance in other bacteria is determined by thresholds published in Clinical Laboratory Standards Institute M100-ED30:2020.

Please contact the HAI program at 206-418-5500 for any questions or comments about this report, or for information on becoming a sentinel lab in Washington State.

Additional Resources

Carbapenem-resistant Enterobacteriaceae (CRE)

Information on CRE from CDC

Case Definition (PDF)

CRE Guideline (PDF)

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