Serious Pseudomonas infections associated with endoscopic retrograde cholangiopancreatography

After observing a single case of Pseudomonas aeruginosa bacteremia following endoscopic retrograde cholangiopancreatography (ERCP), six other P. aeruginosa infections that were temporally related to ERCP were retrospectively found over one year (August 1985 through July 1986) at LDS Hospital. In all seven patients, infection developed within five days after an ERCP. Five patients had bacteremia and two had cholangitis. All five of the Pseudomonas isolates available for testing were serotype 010. Cultures from the ERCP endoscope and several other endoscopes also yielded P. aeruginosa serotype 10, as did environmental cultures from equipment used to clean endoscopes. Among 167 ERCPs performed during the outbreak period, no other patient acquired P. aeruginosa infection. Each of the patients in the outbreak received the first scheduled ERCP of the day. The mean duration between the cleaning of the ERCP endoscope and its subsequent use was significantly longer in cases than in matched controls, a factor that may have permitted contaminating organisms to achieve high inocula in the inadequately cleaned endoscope. Epidemic control measures included improved disinfection of endoscopes, ongoing surveillance, and appropriate antimicrobial prophylaxis. This experience suggests that exogenous infection with Pseudomonas is associated with ERCP, that protracted and insidious outbreaks may occur, and that the occurrence of even a single case of Pseudomonas infection after ERCP should stimulate an epidemiologic investigation.