Bacterial Etiology and Antimicrobial Susceptibility Profiles in Pediatric Cholangitis

Abstract: This study investigated the bacterial etiology and antimicrobial susceptibility profiles of 210 children aged 1 month to <16 years who were diagnosis cholangitis between January 2021 and May 2026. The median age at hospital admission was 7.15 months, and biliary atresia with a history of Kasai portoenterostomy was the predominant underlying hepatobiliary condition (86.7%). Blood cultures were positive in 31.4% of patients, while bile cultures were positive in 4 of 8 patients from whom bile specimens were obtained. Gram-negative bacteria predominated (88.6%), with Escherichia coli and Klebsiella pneumoniae being the most frequently isolated pathogens, each accounting for 38.6% of isolates. E. coli demonstrated the highest susceptibility to amikacin (92.0%), meropenem (83.3%), and ertapenem (81.0%), whereas susceptibility among K. pneumoniae isolates was lower (84.6%, 57.9%, and 69.2%, respectively). Susceptibility to second- and third-generation cephalosporins, which are commonly used for the treatment of biliary tract infections, was below 30% for both E. coli and K. pneumoniae. Susceptibility to fourth-generation cephalosporins was higher but remained suboptimal, at 63.0% for E. coli and 41.7% for K. pneumoniae. These findings indicate a predominance of Gram-negative pathogens and substantial antimicrobial resistance among pediatric biliary tract infections, particularly to commonly used cephalosporins. Amikacin and carbapenems demonstrated comparatively higher in vitro activity, although antimicrobial selection should be guided by local susceptibility patterns and individual clinical circumstances. Keywords: biliary tract infection; antimicrobial susceptibility; bacterial etiology; antimicrobial resistance; children; biliary atresia.