Objective:To investigate the pathogen distribution and influencing factors for pulmonary infection after radical resection of esophageal cancer.Methods:The retrospective case-control study was conducted. The clinical data of 555 patients who underwent radical resection of esophageal cancer in Heping Hospital Affiliated to Changzhi Medical College from January 2021 to December 2022 were collected. There were 344 males and 211 females, aged (64±8)years. Obser-vation indicators: (1) incidence of postoperative pulmonary infection and pathogen distribution; (2) analysis of influencing factors for postoperative pulmonary infection. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was conducted using the t test. Count data were described as absolute numbers or percentages, and comparison between groups was conducted using the chi-square test. The comparisons of ordinal data were analyzed using the nonparametric test. Univariate analysis was performed using the corresponding statistical methods based on data type. Multivariate analysis was performed using the Logistic stepwise regre-ssion model advance method. Results:(1) Incidence of postoperative pulmonary infection and pathogen distribution. Among 555 patients, 91 cases had postoperative pulmonary infection, with the incidence as 16.40%(91/555). In 91 patients with postoperative pulmonary infection, 59 strains of bacteria were isolated and cultured. There were 53 strains of gram-negative bacteria, 3 strains of gram-positive bacteria and 3 strains of fungi, including 20 multidrug-resistant bacteria. Among the 53 strains of gram-negative bacteria, there were 18 strains of Acinetobacter baumannii (12 strains were multidrug resistant), 18 strains of Klebsiella pneumoniae (3 strains were multidrug resistant), 6 strains of Pseudomonas aeruginosa (2 strains were multidrug resistant), 2 strains of Escherichia coli, 2 strains of Enterobacter cloacae, and 2 strains of Haemophilus influenzae (2 strains of Escherichia coli and 1 strain of Enterobacter cloacae were multidrug resistant strains), 1 strain of Serratia marcescens, 1 strain of Citrobacter keri, 1 strain of Corynebacterium striatum, 1 strain of Proteus mirabilis and 1 strain of Klebsiella acidogenes. Among the 3 strains of Gram-positive bacteria, there were 2 strains of Staphylococcus aureus and 1 strain of Streptococcus pneumoniae. All the three strains of fungi were Candida albicans. Among the 18 strains of Acinetobacter baumannii, there were 12, 12, 11, 9, 8, 6 and 5 strains resistant to imipenem, ceftriaxone, ceftazidme, cefoperazone or sulbactam, ciprofloxacin, amicacin and levofloxacin, respectively. The above indexes of 18 strains of Klebsiella pneumoniae were 0, 1, 1, 1, 2, 0 and 2, respectively. (2) Analysis of influencing factors for postoperative pulmonary infection. Results of multivariate analysis showed that tumor pathological staging as stage Ⅱ and Ⅲ, duration of preoperative hospital stay ≥6 days, operation time ≥240 minutes, mode of operation as thoracotomy, type of antibiotics used in peri-operative period ≥3, and postoperative antibiotic use time ≥5 days were independent risk factors for postoperative pulmonary infection ( P<0.05). Conclusions:The main pathogenic bacteria of pulmonary infection after radical resection of esophageal cancer are Acinetobacter baumannii and Klebsiella pneumoniae. Tumor pathological staging as stage Ⅱ and Ⅲ, duration of preoperative hospital stay ≥6 days, operation time ≥240 minutes, mode of operation as thoracotomy, type of antibiotics used in perioperative period ≥3, and postoperative antibiotic use time ≥5 days are independent risk factors for pulmonary infection in patients with esophageal cancer after radical surgery.