Objective To investigate the effects of different preoperative biliary drainage methods on bile bacterial culture and drug resistence of malignant obstructive jaundice.

Methods The retrospective and descriptive study was conducted. The clinical data of 317 patients with malignant obstructive jaundice who were admitted to the First Medical Center of Chinese PLA General Hospital from January 2015 to December 2018 were collected. There were 216 males and 101 females, aged (62±10)years. Of 317 patients, 158 cases had no preoperative biliary drainage, 115 received preoperative biliary drainage by percutaneous transhepatic choledochal drainage (PTCD), 44 received preoperative biliary drainage by endoscopic retrograde biliary drainage (ERBD). Observation indicators: (1) bile bacteria in different preoperative biliary drainage methods; (2) clinicopathological characteristics of patients with positive bile bacteria; (3) drug resistance of bile bacteria in different methods of preoperative biliary drainage. Measurement data with normal distribution were expressed as Mean±SD. Count data were expressed as absolute numbers or percen-tages, and comparison between groups was analyzed by the chi-square test. Bonferroni correction was used for pairwise comparison. The inspection level was 0.016 7 in the multiple comparison.

Results (1) Bile bacteria in different preoperative biliary drainage methods: of 317 patients, 116 cases were positive for bacterial culture, including 168 strains of 43 bacterial types. There were 46 strains from 36 patients without preoperative biliary drainage, 49 strains from 39 patients with preoperative PTCD and 73 strains from 41 patients with preoperative ERBD. ① The positive rate of bacteria for 317 patients was 36.59%(116/317). The positive rates of bacteria for patients without preoperative biliary drainage, patients with preoperative PTCD and patients with preoperative ERBD were 22.78%(36/158), 33.91%(39/115) and 93.18%(41/44). There was a significant difference in the positive rate of bacteria among the three groups (χ²=74.066, P<0.05). There was no significant difference between patients with preoperative PTCD and patients without preoperative biliary drainage (χ²=4.137, P>0.016 7), but there were significant differences between patients with pre-operative ERBD and patients without preoperative biliary drainage or patients with preoperative PTCD (χ²=72.305, 44.718, P<0.016 7). ② The overall multiple bacterial rate was 36.21%(42/116). The multiple bacterial rates for patients without preoperative biliary drainage, patients with preoperative PTCD and patients with preoperative ERBD were 19.44%(7/36), 23.08%(9/39) and 63.41%(26/41). There was a significant difference in multiple bacterial rate among the three groups (χ²=20.431, P<0.05). There was no significant difference between patients with PTCD and patients without preoperative biliary drainage (χ²=0.147, P>0.016 7), but there were significant differences between patients with preoperative ERBD and patients without preoperative biliary drainage or patients with preoperative PTCD (χ²=15.133, 13.215, P<0.016 7). ③ The overall prevalence rate of multi-drug resistant organism was 30.95%(52/168). The prevalence rates of multi-drug resistant organism for patients without preoperative biliary drainage, patients with preoperative PTCD and patients with preoperative ERBD group were 15.22%(7/46), 26.53%(13/49) and 43.84%(32/73). There was a significant difference in the prevalence rate of multi-drug resistant organism among the three groups (χ²=11.447, P<0.05). There was no significant difference between patients with PTCD and patients without preoperative biliary drainage (χ²=1.827, P>0.016 7). There was a significant difference between patients with preoperative ERBD and patients without preoperative biliary drainage (χ²=10.497, P<0.016 7), but there was no significant difference between patients with preoperative ERBD and patients with preoperative PTCD (χ²=3.772, P>0.016 7). (2) Clinicopatho-logical characteristics of patients with positive bile bacteria: age, the history of abdominal surgery, degree of jaundice and location of biliary obstruction of patients were not related to the positive rate of bacterial culture (χ²=4.865, 1.423, 4.922, 0.030, P>0.05). (3) Drug resistance of bile bacteria in different methods of preoperative biliary drainage: for patients without preoperative biliary drainage, the drug resistance rate of Gram-positive bacteria to nitrofurantoin, linezolid and tigecycline was 0, and the drug resistance rate of Gram-negative bacteria to piperacillin/tazobactam, gentamicin, tobramycin, amikacin and imipenem was 0. For patients with PTCD, the drug resistance rate of Gram-positive bacteria to linezolid and tigecycline was 0. For patients with ERBD, the drug resistance rate of Gram-positive bacteria to linezolid and tigecycline was 0. In terms of Gram-positive bacteria, linezolid, tigecycline, vancomycin and nitrofurantoin were the top four antibiotics with the lowest resistance rate. In terms of Gram-negative bacteria, imipenem, piperacillin/tazobactam, amikacin and tobramycinn were the top four antibiotics with the lowest resistance rate. Seven strains of fungi showed no resistance to antifungal drugs.

Conclusions Patients with preoperative ERBD are more vulnerable to infectious complications, and more likely to form drug resistant organism and multi-drug resistant organism. For Gram-positive bacteria infection, linezolid, tigecycline and vancomycin can be used for treatment. For Gram-negative bacteria infection, imipenem, piperacillin/trzobactam, amikacin and tobramycin can be used for treatment.