Abstract: Objective  To analyze the distribution and characteristics of drug resistanceof pathogenic bacteria in bile culture in the First Affiliated Hospital of Nanjing Medical University, so as to provide evidence for diagnosis and treatment of biliary tract infection. 
Methods  A total of 1 264 strains of pathogenic bacteria isolated from clinical bile specimens and clinical data of patients with infected by drug-resistant bacteria in our hospital were analyzed retrospectively. VITEK-2 Compactautomatic microbial identification and drug susceptibility systemwas used for the identification of bacteria and drug susceptibility test, and the drug sensitivity analysis was performed by WHONET 5.6 software, while SPSS 22.0 software was used to analyze the prognosis of resistant bacterial infection. 
Results  A total of 1 264 positive strains were isolated from clinical bile culture with a positive culture rate of 32.1%. 780(61.7%) gram-negativestrains and 417(33.0%) and gram-positive strains were identified, with 67(5.3%) strains of fungi. Escherichia coli(25.9%), Klebsiella pneumoniae(10.9%), Enterococcus faecalis(11.7%) and Enterococcus faecalis(8.9%) were the main strains. Drug sensitivity test results showed that the sensitivity of Enterobacteriaceae bacteria to carbapenems, aminoglycosides and piperacillin/tazobactam was high(>59.9%); Pseudomonas aeruginosa was highly sensitiveto the remaining antibacterial drugs(>52.6%) except for ampicillin/sulbacillin and cotrimoxazole; the sensitivity of Acinetobacter baumannii to common antibiotics was less than 47.4%; Enterococcus is highly sensitive to high concentration of gentamicin, high concentration of streptomycin, linezolid and vancomycin(>63.3%).No vancomycin-resistant enterococcus was found except for Enterococcus naturally resistant to vancomycin. A total of 50 strains of Carbapenem-Resistant Enterobacteriaceae(CRE)were isolated, of which 62.0% were klebsiella pneumoniae and 26.0% were Escherichia coli. Most of the patients with biliary tract infection of CRE were male, aged over 50 years, with malignant tumor, liver transplantation, trauma and other serious primary diseases, with a history of surgery and bile drainage, and combinedbloodstream infection. The prognosis of patients with positive CRE cultured in bile was affected by the type of CRE bacteria and presence or absence of gastrointestinal hemorrhage, among which Carbapenem-Resistant Klebsiella pneumoniae(CR-KPN) was an independent risk factor for poor prognosis in patients with CRE cultured from bile. 
Conclusion  Enterobacteriaceae bacteria and Enterococcus bacteria are the main pathogens for biliary tract infection in our hospital, and biliary infections of CRE are severe. In clinical practice, clinicians should focus on the prevention of multiple drug-resistant bacteria，evaluate the prognosis according to the type of CRE and provide timely intervention. In addition,high-risk patients should be actively screened forearly removal of colonization resistant bacteria, to reduce the mortality of biliary tract infections. 

Key words: biliary tract, infection, anti-bacterial agents