Abstract: OBJECTIVE To analyze the prevalence of surgical site infections, distribution and drug resistance of pathogens isolated from the patients with lower limb fractures and define risk factors for the infections. METHODS The clinical data were retrospectively collected from 5000 lower limb fracture patients who received surgical procedures in Tianjin Fifth Central Hospital from Jan. 2017 to Jan. 2024. The results of culture of pathogens for the patients with surgical site infections and antimicrobial susceptibility testing were observed. Univariate analysis and multivariate logistic regression analysis were performed for the risk factors for the surgical site infections. RESULTS Among the 5000 lower limb fracture patients, 213 (4.26%) had infections, 64.79% of whom had superficial incision infections,26.76% had deep incision infections,and 8.45% had organ/cavity infections. Totally 247 strains of pathogens were isolated from the patients with infections, of which 142 (57.49%) were gram-positive bacteria (Staphylococcus aureus (55 strains) accounted for 22.27%, of which 24 (43.64%) were methicillin-resistant Staphylococcus aureus), 98(39.68%)were gram-negative bacteria (Pseudomonas aeruginosa (28 strains) accounted for 11.34%, Escherichia coli (24 strains) accounted for 9.72%, of which 15 (62.50%) were extended-spectrum β-lactamases (ESBLs)-producing strains. Multivariate analysis showed that the no less than 65 years of age, BMI no less than 24.0 kg/m², diabetes mellitus, smoking history, operation duration more than 2 hours and unreasonable use of antibiotics were the risk factors for the surgical site infections in the patients with lower limb fractures(P＜0.05). CONCLUSIONS The gram-positive bacteria are dominant among the pathogens causing the surgical site infections in the patients with lower limb fractures. The pathogens are highly resistant to antibiotics. In response to the risk factors such as the advanced age, severe open fracture, and delayed surgery, it is necessary to take targeted prevention and control measures and reasonably use antibiotics based on the result of antimicrobial susceptibility testing.