Microbial profile of biliary tract infection in patients undergoing therapeutic endoscopic retrograde cholangiopancreatography (ERCP), and baseline risk factors predicting microbial growth and post-ERCP cholangitis

Introduction
Stasis of bile flow can result in microbial colonization of the biliary tree. Cholangitis is a common adverse event linked to endoscopic retrograde cholangiopancreatography (ERCP).

Aim
To establish the bacterial profiles isolated from the bile sample and to evaluate the pre-ERCP risk factors predicting the microbial growth and development of post-ERCP cholangitis (PEC).

Material and methods
This was a prospective cohort study, which was conducted at the Department of Hepato-gastroenterology, SIUT from 1 January 2021 to 31 December 2021. Patients of either gender undergoing index ERCP procedure were included in the study. All the patients underwent ERCP, and bile culture (BC) aspirated immediately after cannulation was achieved prior to the contrast injection. There were 2 outcome variables. One was the presence or absence of organisms in bile culture, and the second one was the development of PEC.

Results
The total number of patients was 280. Bile culture was positive in 195 (69.6%) patients, and post-ERCP cholangitis developed in 187 (66.8%) patients. The most common organism in BC was Escherichia coli (E. coli), in 82 (42%) patients. History of jaundice, abdominal pain, and weight loss on admission along with ERCP performed for common bile duct (CBD) stricture were independent predictors of positive BC and PEC, while advanced age was an additional risk factor for PEC.

Conclusions
Microbial profile and risk factors for positive BC and PEC were evaluated. Advanced age, pre-operative jaundice, and prolonged biliary stasis are the independent risk factors for these conditions.