Risk of bacterial colonization of pancreatic stents used in endoscopic retrograde cholangiopancreatography

BACKGROUND:: Pancreatic stents (PSs) are commonly inserted at the time of endoscopic retrograde cholangiopancreatography to reduce the risk of pancreatitis. If left in situ for more than 2 weeks, they have been associated with pancreatic duct injury. The mechanism of this injury is not clear, but it may be related to bacterial colonization. AIM:: To determine the incidence of PS colonization by microorganisms and the relationship between such colonization and the type, length, diameter, and duration of PSs in situ. METHODS:: A series of endoscopic retrograde cholangiopancreatographies performed by a single operator in a tertiary referral centre during which a PS was placed was analysed. In each case, after removing the PS, the segment of the PS, which had been intraluminal, was sent for microbiological analysis. Microscopy and culture results were compared with stent length (cm), time in situ (d), demographic information, and clinical course. RESULTS:: Of the 47 PSs sent for culture, 28 grew clinically significant bacteria. The majority of organisms cultured were of the Klebsiella, Escherichia, Enterobacter, and Enterococcus genera. Time in situ was found to correlate strongly with the growth of clinically significant organisms using a logarithmic regression analysis tool (coefficient=0.36, change of variance=6.43, P=0.01). In addition, 1 patient developed Enterobacter septicaemia almost certainly related to stent colonization, which necessitated urgent removal of the stent 10 days after insertion. CONCLUSION:: Colonization of PSs by pathogenic organisms is common and related to duration in situ of the PS. Enteric organisms are frequently implicated. Although significant clinical sequelae are infrequent, we suggest that PSs should not be left in situ for >7 to 10 days due to the significant risk of bacterial colonization.