Objective To investigate the characteristics and risk factors of biliary pathogens infection in patients with acute pancreatitis（AP）. Methods A total of 360 patients with AP attending a hospital in Henan Province from July 2019 to February 2021 were selected. Bile samples from patients with biliary tract infection were collected for bacterial culture

strain identification

and drug sensitivity analysis. The multi-factor logistic regression was adopted to analyze the risk factors in the occurrence of biliary tract infection in patients with AP. Results The incidence of biliary tract infection in 360 cases of AP was 20.83%（75/360）

and a total of 90 pathogenic bacteria were isolated

of which Gram-negative

Gram-positive and fungal bacteria accounted for 64.44%

30.00% and 5.56%

respectively. Among the major Gram-negative bacteria

Escherichia coli had higher resistance rates to piperacillin

ciprofloxacin and cefazolin

with a drug resistance rate of 85.00%

70.00% and 55.00%

respectively; Klebsiella pneumoniae had higher resistance rates to piperacillin

ceftazidime and ciprofloxacin

with a drug resistance rate of 86.67%

73.33% and 60.00%

respectively. Among the major Gram-positive bacteria

Staphylococcus aureus had higher resistance rates to penicillin

erythromycin

and ampicillin

with a drug resistance rate of 80.00%

60.00%

and 50.00%

respectively; and Staphylococcus epidermidis had higher resistance rates to penicillin

ampicillin

and erythromycin

with a drug resistance rate of 85.71%

71.43%

and 57.14%

respectively. The results of multi-factor logistic regression analysis showed that old age

invasive operation

combined biliary tract disease

and APACHE Ⅱ score over 11 were the risk factors in the development of biliary tract infection in patients with AP（P<0.05）. Conclusion Patients with AP combined with biliary tract infection indicate certain pathogenic characteristics

and the infecting pathogens are mainly Gram-negative bacteria

and relatively sensitive drugs such as teicoplanin and vancomycin can be preferred for treatment. Special attention should be paid on the development of AP patients clinically

such as old age and combined biliary tract diseases to prevent the occurrence of biliary tract infection.