Microbiology of bile aspirates obtained at ERCP in patients with suspected acute cholangitis

The cornerstone of treatment for acute cholangitis is source control with biliary drainage and early antibiotics. The primary aim of this study was to describe the microbiology of bile aspirate pathogens obtained at the time of endoscopic retrograde cholangiopancreatography (ERCP) in patients suspected of having acute cholangitis.

In this single-center retrospective study, patients were included if a bile aspirate was collected at ERCP for suspicion of acute cholangitis, from 1 January 2010 to 31 December 2016.

There were 721 ERCP procedures for suspected acute cholangitis with bile culture results, with 662 positive bile cultures (91.8 %). Pathogens included: Enterococcus species (spp.) 448 (67.7 %); Klebsiella spp. 295 (44.6 %); Escherichia coli 269 (40.6 %); Pseudomonas spp. 52 (7.9 %); and anaerobes 64 (9.7 %). Susceptibility of Klebsiella pneumoniae and E.coli isolates to ciprofloxacin was 88 % and 64 %, respectively. Extended-spectrum beta-lactamases and carbapenem resistance were found in 7.9 % and 3.6 % of Enterobacteriaceae, respectively. There were 437 concurrent blood cultures, of which 174 were positive (39.8 % of cultures drawn). Prior biliary endoscopic sphincterotomy (ES) was evident in 459 ERCP cases (63.7 %), and was associated with increased frequency of Klebsiella spp., Pseudomonas aeruginosa, Enterobacter spp., and Enterococcus spp. Prior biliary ES significantly increased the probability of vancomycin-resistant Enterococcus (VRE).

The vast majority of bile cultures (91.8 %) were positive. The susceptibilities of E.coli and K.pneumoniae to ciprofloxacin are lower than historically noted. A notable portion of cultures contained pathogenic drug-resistant organisms. Prior biliary ES is associated with a higher frequency of certain organisms and higher frequency of VRE.