The Presence and Significance of Bacteria and Fungi in Bile Aspirated During ERC—A Retrospective Analysis

<b>Background:</b> Infections of the biliary tract are found frequently in pathologically or surgically altered bile ducts. Mostly these infections result from the ascent of bacteria or fungi from the small bowel, although hematogeneous infections of the biliary system may also occur. The biliary sphincter and the continuous flow of bile are thought to prevent or limit ascending infections. Obstructive alterations in the biliary system are the most frequent indication of endoscopic retrograde cholangiography (ERC). The aim of this study was to analyze the spectrum and frequency of microbes within the bile, and discover the influence of earlier sphincterotomy. <b>Methods:</b> In our department, we routinely aspirate bile for microbiologic culture during ERC. For this study, all ERC performed in 2014–2018 were retrospectively analyzed, including all microbiological reports. Indications for the endoscopic examination were also recorded. In addition, the findings were correlated with whether or not a sphincterotomy had been previously performed, and whether or not there had been antibiotic treatment prior to the examination. <b>Results:</b> A total of 2253 successful standard ERC procedures were performed between 2014 and 2016. In 486 cases, bile was aspirated and sent for microbiologic culture. In total, 1220 bile samples were analyzed, and bacteria or fungi were found in 1029 (86.0%). <i>Enterococci</i> and <i>Enterobacter</i> were found most commonly, but <i>E. coli</i>, <i>streptococci</i>, <i>klebsiella</i>, and <i>staphylococci</i> were also found. In 11.2% of positive cultures, multiresistant pathogens were identified. In up to 29% <i>Candida</i> spp., most commonly, <i>Candida albicans</i> (68%) were also found, either alone or in conjunction with bacteria. Neither prior sphincterotomy nor the use of peri-interventional antibiotics had a major influence on the frequency with which positive bile cultures were detected. <b>Conclusions:</b> Aspiration of bile during ERC is of high clinical relevance, because microbiological analysis reveals the frequent presence of bacteria and fungi, knowledge of which may be useful for deciding on anti-infective treatment.