Endoscopic retrograde cholangiopancreatography-obtained bile culture in acute cholangitis: retrospective analysis of bile cultures and risk factors in a tertiary care center.

Background: Collection of bile aspirate during endoscopic retrograde cholangiopancreatography (ERCP) is essential to identify pathogens responsible for acute cholangitis. Limited data are available on the risk factors for the presence of multidrug-resistant organisms (MDRO) in bile.

Methods: We conducted this retrospective, single-center study to assess the prevalence and susceptibility rates of bacteria in bile cultures, and the risk factors for the presence of pathogens, MDRO, and fungi in bile. All consecutive patients who underwent biliary drainage for acute cholangitis from January 2017 to December 2019 were included.

Results: 443/1610 ERCPs were performed for acute cholangitis. Bile culture was collected in 91.4% (405/443), of which 86.7% were positive. Most common isolates were Enterococcus faecalis (37.6%) and Escherichia coli (32.8%). Vancomycin resistance was found in 9.9% of Enterococcus species (spp.); extended-spectrum beta-lactamases (ESBL) and carbapenemases in 11.2% and 0.9% of Enterobacteriaceae, respectively. The empiric antimicrobial therapy was changed in 26.4% (n = 107) of cases, with a clinical response in 90.7%. In multivariate analysis, biliary stenting was an independent risk factor for positive bile culture (odds ratio [OR] 9.43; P < 0.01). Independent risk factors for MDRO in bile were patient age>60 years (OR 2.51; P = 0.03), previous sphincterotomy (OR 2.57; P = 0.02), and biliary stenting (OR 2.80; P < 0.01). Previous sphincterotomy was the only risk factor for isolation of fungi in bile (OR 1.61; P = 0.04).

Conclusions: Our study showed an increasing prevalence of Enterococcus spp. and MDRO. Bile cultures should be routinely collected in cholangitis and in patients with repeated ERCPs to allow more efficient antimicrobial treatment.