Abstract: Objective: To analyze the related factors,bile pathogen distribution and sensitivities of commonly used antibacterial drug in clinic for the treatment of malignant obstructive jaundice complicated with biliary infection,and provide the reference in the reasonable application of antibiotics for biliary infection.Methods: The clinical data of endoscopic retrograde cholangiopancreatography(ERCP) and percutaneous transhepatic cholangiodrainage(PTCD) in 106 cases with malignant obstructive jaundice complicated with biliary infection were retrospective analyzed,and 65 cases with high malignant obstructive jaundice and 41 cases with low malignant obstructive jaundice were found.The bile was harvested through intraoperative intubation into biliary tract in ERCP,and the bile was harvested through the drainage of 7 F or 8 F puncture tube into the biliary tract in PTCD.The bile bacteria culture,blood culture and various relevant factors were investigated,and the relationships between bacterial spectrum,and obstruction location and other related factors were analyzed.Results: Among 106 cases,the bile culture was positive in 52 cases.The main pathogenic bacteria of biliary infection were Escherichia coli(33.0%),Klebsiella pneumoniae(9.61%),Enterobacter cloacae(9.61%),Streptococcus viridans(5.77%),Staphylococcus epidermidis(5.77%),Streptococcus sanguis type Ⅰ(5.77%),Enterococcus faecium(3.85%),Streptococcus hemolyticus(3.85%) and Pseudomonas putida bacteria(3.85%) in turn.The sensitivities of gram-positive cocci to vancomycin,linezolid and imipenem were 100%.The sensitivities of gram-negative bacilli to ertapenem,imipenem,sulbactam/cefoperazone,cotrimoxazole,gentamicin and amikacin were 100%.The ESBL positive rates of Escherichia coli and Klebsiella pneumonia were 70.6% and 40.0%,respectively.The logistic regression equation analysis showed that the age,low biliary obstruction,and combination of biliary tract infection symptoms were the independent risk factors of biliary infection.Conclusions: The Escherichia coli is the main infection bacterium of biliary tract in patients with malignant obstructive jaundice.The bacterium is more likely to be detected in bile culture in elderly,C-reactive protein increasing,low biliary obstruction and biliary tract infection patients.