Pseudomonas aeruginosa and Enterobacteriaceae bacteremia after biliary endoscopy: an outbreak investigation using DNA macrorestriction analysis

Am J Med. 1993 Nov;95(5):489-98. doi: 10.1016/0002-9343(93)90331-i.


Purpose: An outbreak of gram-negative bacteremia in patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) was investigated to determine the sources of infection and to control transmission.

Patients, methods, and results: The incidence of post-ERCP bacteremia increased from 1.6% (60 of 3,696) procedures to 3.6% (53 of 1,454) procedures (relative risk 2.3, p < 0.0001) after endoscopes were processed in a new automated disinfector. Bacteremia involved nine species of Pseudomonas and Enterobacteriaceae, which were also isolated from processed endoscopes. Seven epidemic strains with highly related genomic macrorestriction profiles each infected 2 or more patients, accounting for 29 (55%) episodes of post-ERCP bacteremia. Strains recovered from endoscopes and from the disinfector were associated with 22 (42%) and 5 (9%) bacteremic episodes respectively. Effective endoscope disinfection was achieved by cleansing and disinfection of a blind channel not processed in the disinfector, additional isopropanol-air flush of all channels, and auto-disinfection of the disinfector. In the following period, the incidence of post-ERCP bacteremia returned to the pre-epidemic rate (1.7%, p = 0.0001).

Conclusion: Bacterial genome fingerprinting by macrorestriction analysis enabled delineation of a multi-strain outbreak of post-ERCP bacteremia. Cross-contamination, and to a lesser extent, common-source contamination, appeared related to inadequate disinfection of endoscopes processed in an automated disinfector.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteremia / epidemiology
  • Bacteremia / etiology*
  • Bacteremia / microbiology
  • Bacteremia / prevention & control
  • Bacterial Typing Techniques
  • Cholangiopancreatography, Endoscopic Retrograde / adverse effects*
  • DNA Restriction Enzymes
  • DNA, Bacterial / genetics
  • Disease Outbreaks*
  • Disinfection / methods
  • Electrophoresis, Gel, Pulsed-Field
  • Enterobacteriaceae Infections / epidemiology
  • Enterobacteriaceae Infections / prevention & control
  • Enterobacteriaceae Infections / transmission*
  • Humans
  • Pseudomonas Infections / epidemiology
  • Pseudomonas Infections / prevention & control
  • Pseudomonas Infections / transmission*
  • Seroepidemiologic Studies


  • DNA, Bacterial
  • DNA Restriction Enzymes