Abstract: Objective To investigate the distribution and drug resistance of pathogenic bacteria in 105 patients with common bile duct stones complicated by biliary tract infection. Methods A total of 105 patients admitted to our hospital from June 2019 to January 2023 were selected for the study, comprising 58 males and 47 females with an average age of (49.6 ± 10.5) years. Based on the condition of the stones, the patients were divided into two groups: the initial group and the recurrent group. General information about the subjects, including gender, age, clinical presentation, laboratory test results, and imaging examination results, was collected. Endoscopic retrograde cholangiopancreatography (ERCP) was performed by experienced doctors using Olympus electronic duodenoscopy. Following the ERCP procedure, 5-10 mL of bile was collected through the nasobiliary duct. The collected bile samples were transferred into sterile test tubes and sent to our hospital laboratory for bacterial culture and analysis. The bile samples were cultured for 48-72 hours, after which the bacterial strains were isolated and identified using the VITEK 2 Compact fully automatic bacterial analyzer. Drug sensitivity tests on bacterial strains were performed using the paper agar diffusion method. The study observed the subject's history of antibiotic use, the positive rate and distribution of bile strain cultures, and the antibiotic resistance of the bacteria found in the bile. Results Based on the condition of the stones, there were 55 cases in the initial group and 50 cases in the recurrent group. The initial group had a higher rate of antibiotic use, compared to the recurrence group(P<0.05). The positive rates of bile culture in the initial and recurrent groups were 83.6% and 94.0%, respectively, and the disfference was statistically significant (P<0.05). The recurrence group showed a significant increase in Gram-negative bacteria and Escherichia coli, compared to the initial group(P<0.05). There was no significant difference in the distribution of other pathogens between the initial and recurrent groups (P>0.05). Furthermore, the antibiotic resistance rate of pathogens was significantly higher in the recurrent group, with notably enhanced resistance (P<0.05). Conclusion The distribution of pathogens in patients with initial and recurrent common bile duct stones complicated by biliary tract infections is similar. However, pathogen resistance in the recurrent group is higher than in the initial group. Clinical doctors should carefully choose antibiotics based on the patient's stone recurrence and resistance testing results.

Key words: Common bile duct stones, Biliary tract infection, Bile culture, Distribution of pathogenic bacteria, Drug resistance analysis