New Delhi metallo-β-lactamase-producing carbapenem-resistant Escherichia coli associated with exposure to duodenoscopes

JAMA. 2014 Oct 8;312(14):1447-55. doi: 10.1001/jama.2014.12720.


Importance: Carbapenem-resistant Enterobacteriaceae (CRE) producing the New Delhi metallo-β-lactamase (NDM) are rare in the United States, but have the potential to add to the increasing CRE burden. Previous NDM-producing CRE clusters have been attributed to person-to-person transmission in health care facilities.

Objective: To identify a source for, and interrupt transmission of, NDM-producing CRE in a northeastern Illinois hospital.

Design, setting, and participants: Outbreak investigation among 39 case patients at a tertiary care hospital in northeastern Illinois, including a case-control study, infection control assessment, and collection of environmental and device cultures; patient and environmental isolate relatedness was evaluated with pulsed-field gel electrophoresis (PFGE). Following identification of a likely source, targeted patient notification and CRE screening cultures were performed.

Main outcomes and measures: Association between exposure and acquisition of NDM-producing CRE; results of environmental cultures and organism typing.

Results: In total, 39 case patients were identified from January 2013 through December 2013, 35 with duodenoscope exposure in 1 hospital. No lapses in duodenoscope reprocessing were identified; however, NDM-producing Escherichia coli was recovered from a reprocessed duodenoscope and shared more than 92% similarity to all case patient isolates by PFGE. Based on the case-control study, case patients had significantly higher odds of being exposed to a duodenoscope (odds ratio [OR], 78 [95% CI, 6.0-1008], P < .001). After the hospital changed its reprocessing procedure from automated high-level disinfection with ortho-phthalaldehyde to gas sterilization with ethylene oxide, no additional case patients were identified.

Conclusions and relevance: In this investigation, exposure to duodenoscopes with bacterial contamination was associated with apparent transmission of NDM-producing E coli among patients at 1 hospital. Bacterial contamination of duodenoscopes appeared to persist despite the absence of recognized reprocessing lapses. Facilities should be aware of the potential for transmission of bacteria including antimicrobial-resistant organisms via this route and should conduct regular reviews of their duodenoscope reprocessing procedures to ensure optimal manual cleaning and disinfection.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Carbapenems / pharmacology*
  • Case-Control Studies
  • Cohort Studies
  • Cross Infection / epidemiology
  • Disease Outbreaks
  • Disinfection / methods*
  • Drug Resistance, Bacterial
  • Duodenoscopes / microbiology*
  • Enterobacteriaceae Infections / epidemiology
  • Enterobacteriaceae Infections / etiology*
  • Equipment Contamination*
  • Escherichia coli* / enzymology
  • Escherichia coli* / isolation & purification
  • Female
  • Hospitals
  • Humans
  • Illinois / epidemiology
  • Male
  • Middle Aged
  • beta-Lactamases


  • Carbapenems
  • beta-Lactamases
  • beta-lactamase NDM-1