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


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).


CONCLUSIONS
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.
Struelens
M J
MJ
Department of Microbiology, Hôpital Erasme, Université Libre de Bruxelles, Belgium.
Rost
F
F
Deplano
A
A
Maas
A
A
Schwam
V
V
Serruys
E
E
Cremer
M
M
D016470:Bacteremia / Q000453:epidemiology / Q000209:etiology* / Q000382:microbiology / Q000517:prevention & control; D015373:Bacterial Typing Techniques; D002760:Cholangiopancreatography, Endoscopic Retrograde / Q000009:adverse effects*; D004262:DNA Restriction Enzymes; D004269:DNA, Bacterial / Q000235:genetics; D004196:Disease Outbreaks; D004203:Disinfection / Q000379:methods; D016521:Electrophoresis, Gel, Pulsed-Field; D004756:Enterobacteriaceae Infections / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission*; D006801:Humans; D011552:Pseudomonas Infections / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission*; D016036:Seroepidemiologic Studies
D004269:DNA, Bacterial; D004262:DNA Restriction Enzymes