Objective To analyze the pathogens distribution, drug resistance and risk factors of bacterial infection in patients undergoing liver transplantation for liver failure.

Methods The retrospective case‑control study was conducted. The clinical data of 88 patients with liver failure who underwent liver transplantation in The First Affiliated Hospital of Xi′an Jiaotong University from July 2020 to June 2023 were collected. There were 57 males and 31 females, aged (44±9)years. Observation indicators:(1) incidence and pathogens distribution of bacterial infection in patients undergoing liver transplantation for liver failure; (2) drug resistance of bacteria; (3) risk factors of bacterial infection in patients undergoing liver transplantation for liver failure. Measurement data with normal distribution were represented as Mean±SD. Measurement data with skewed distribution were represented as M(range). Count data were described as absolute numbers and percentages. Univariate analysis was conducted using the chi‑square test or Fisher exact probability. Multivariate analysis was conducted using the Logistic regression model.

Results (1) Incidence and pathogens distribution of bacterial infection in patients undergoing liver transplantation for liver failure. Of 88 patients, 40 cases had bacterial infection after liver transplantation, with the incidence as 45.45% and occurrence time as postoperative 18(range, 1-57)days. Of the 40 cases with bacterial infection after liver transplantation, 9 cases had single strain infection and 31 cases had mixed bacterial infection. A total of 135 strains of different pathogenic bacteria were isolated from 40 patients, 106 of which were Gram‑negative bacteria, 29 were Gram‑positive bacteria. Of the Gram‑negative bacteria, the top 4 pathogenic bacteria were 37 strains of Acinetobacter baumannii, 35 strains of Klebsiella pneumoniae, 11 strains of Pseudomonas aeruginosa, 9 strains of Stenotrophomonas maltophilia. Of the Gram‑positive bacteria, there were 22 strains of Enterococcus faecium, 3 strains of Staphylococcus aureus, 3 strains of Staphylococcus epidermidis, 1 strain of Staphylococcus haemolyticus. Of the 135 strains of pathogenic bacteria, 64 strains were isolated from respiratory tract, 26 strains were from abdomen, 23 strains were from biliary tract, 16 strains were from blood, 6 strains were from other sites. (2) Drug resistance of bacteria. Of the Gram‑negative bacteria, Acinetobacter baumannii had a resistance rate of lower than 30.0% to colistin, tigacyclinei, minocycline, a resistance rate of 30.0%-50.0% to amikacin and tobramycin, a resistance rate of over 70.0% to cefotetan, ceftazidime, cefepime, cefoperazone/sulbactam, piperacillin/tazobactam, meropenem, imipenem, ciprofloxacin, cotrimoxazole, levofloxacin. Klebsiella pneumoniae showed a resistance rate of lower than 30.0% to ceftazidime/avibactam, colistin, tigacyclinei and a resistance rate of more than 70.0% to other tested antibiotics. Pseudomonas aeruginosa showed a resistance rate of more than 50.0% to meropenem, imipenem, levofloxacin and a resistance rate of lower than 50.0% to other tested antibiotics. Stenotrophomonas maltophilia showed a resistance rate of lower than 30.0% to cotrimoxazole, levofloxacin, minocycline. Klebsiella oxytoca showed a resistance rate of more than 50.0% to piperacillin/tazobactam, cefoperazone/sulbactam and a resistance rate of lower than 50.0% to other tested antibiotics. The resistance rate of Escherichia coli to amikacin, tobramycin, ceftazidime/avibactam, colistin, and tigecycline was less than 30.0%, and the resistance rate to other tested antibiotics was more than 50.0%. Of the Gram‑positive bacteria, Staphylococcus aureus showed a resistance rate of 0 to tigacyclinei, vancomycin, teicoplanin, linezolid, a resistance rate of lower than 50.0% to gentamicin and ciprofloxacin, and a resistance rate of more than 50.0% to erythromycin, penicillin G, ampicillin, tetracycline, levofloxacin. Staphylococcus showed a resistance rate of more than 50.0% to erythromycin, penicillin G, oxacillin, and a resistance rate of 0 to other tested antibiotics. (3) Risk factors of bacterial infection in patients undergoing liver transplantation for liver failure. Results of multivariate analysis showed that preoperative model for end‑stage liver disease score ≥30 was an independent risk factor for bacterial infection in patients undergoing liver transplantation for liver failure (odds ratio=6.440, 95% confidence interval as 2.155-19.248, P<0.05).

Conclusions The incidence of bacterial infection in patients undergoing liver transplantation for liver failure is high, with the most common sites of respiratory tract and abdomen. The pathogenic bacteria are mainly Gram‑negative bacteria, which show an extensive and high drug resistance. Preoperative model for end‑stage liver disease score ≥30 was an independent risk factor for bacterial infection in patients undergoing liver transplantation for liver failure.