Objective To investigate the risk factors for abdominal infection after liver transplantation (LT).

Methods The retrospective case‑control study was conducted. The clinical data of 356 patients who underwent LT in the First Affiliated Hospital of Xi′an Jiaotong University from January 2015 to December 2018 were collected. There were 273 males and 83 females, aged from 21 to 67 years, with the median age of 46 years. Observation indications: (1) abdominal infec-tion after LT and distribution of pathogens; (2) analysis of risk factors for abdominal infection after LT; (3) follow‑up and survival. Follow‑up was performed using outpatient examination and tele-phone interview to detect postoperative 1‑year survival rate and cases of death up to June 2020. Measurement data with normal distribution were represented as Mean±SD. Measurement data with skewed distribution were described as M(range). Count data were expressed as absolute numbers or percentages. Univariate analysis was conducted using the chi‑square test, t test, Mann-Whitney U test and Fisher exact probability. Multivariate analysis was done using the Logistic regression model. The Kaplan-Meier method was used to calculate sruvival time and survival rates. Log-Rank test was used for survival analysis.

Results (1) Abdominal infection after LT and distribution of pathogens: 63 of 356 recipients had abdominal infection after LT, with the overall incidence of 17.70%(63/356). Of the 63 recipients, 41 cases had abdominal infection within postoperative 2 weeks, 17 cases had multi-drug resistant organism infection. A total of 116 strains of bacteria were isolated from 63 recipients with abdominal infection, 52 of which were gram‑negative bacteria, 48 were gram-positive bacteria, 16 were fungi. (2) Analysis of risk factors for abdominal infection after LT: results of univariate analysis showed that preoperative model for end‑stage liver disease (MELD) score, preoperative serum albumin, preoperative leukocytes, preoperative prothrombin time, preoperative alanine aminotransferase, preoperative aspartate aminotransferase, operation time, volume of intraoperative blood loss, days of postoperative antibiotic use, postoperative renal failure, postoperative delayed graft function,duration of postoperative intensive care unit stay were related factors for abdominal infection after LT (Z=-2.456, t=-1.982, Z=-3.193, -2.802, -2.336, -2.276, -2.116, -3.217, χ²=15.807, 10.395, 6.750, Z=-4.468, P<0.05). Liver retransplantaiton and postoperative bile leakage were related factors for abdominal infection after LT (P<0.05). Results of multivariate analysis showed that preoperative MELD score>20 and liver retransplantation were independent risk factors for abdominal infection after LT (odds ratio=2.871, 12.875, 95% confidence interval as 1.106-7.448, 1.290-128.521, P<0.05). (3) Follow‑up and survival: 356 recipients were followed up for 1-66 months, with a median follow-up time of 32 months. The postoperative 1‑year overall survival rate of 63 recipients with abdominal infection and 293 recipients without abdominal infection were 84.60% and 97.03%, respectively, showing a significant difference (χ²=11.660, P<0.05). During the follow‑up, 58 recipients died.

Conclusion Preoperative MELD score>20 and liver retransplantation are independent risk factors for abdominal infection after LT.