Analysis of the efficacy of fosfomycin trometamol in preventing biofilm bacterial infection in double-J stents among diabetic patients and the factors associated with infection.

OBJECTIVE: To evaluate the efficacy of fosfomycin trometamol powder (FMT) in preventing biofilm-associated bacterial infections on double-J stents in diabetic patients; to characterize the species distribution and antimicrobial susceptibility patterns of biofilm-forming bacteria isolated from these devices; and to identify clinical and microbiological risk factors associated with such infections-thereby informing evidence-based strategies for infection prevention in this high-risk population.

METHODS: A total of 100 adult diabetic patients who underwent double-J stent placement at our tertiary care center between June 2024 and June 2025 were prospectively enrolled and randomized in a 1:1 ratio to either an experimental group or a control group (n = 50 per group). Patients in the experimental group received a single oral dose of 3 g FMT on the day before stent insertion and on postoperative days 7 and 15; those in the control group received a single oral dose of 0.5 g levofloxacin (LFX) tablets on the day before stent insertion and on postoperative days 1 and 2. At the time of stent removal, stent surface specimens were collected for quantitative biofilm-forming bacterial culture, species identification, and antimicrobial susceptibility testing. Baseline clinical characteristics, stent-related symptoms, and infection outcomes were systematically recorded. Statistical analysis was conducted using SPSS version 26.0, with two-sided p < 0.05 considered statistically significant.

RESULTS: Among the 100 diabetic patients with indwelling double-J stents, biofilm-forming bacterial colonization was detected in 24 (24.0%), with significantly lower prevalence in the experimental group (7/50, 14.0%) than in the control group (17/50, 34.0%) (χ2 = 5.48, p = 0.019). Escherichia coli (E. coli) was the predominant pathogen isolated (accounting for 50% of all positive cultures); among these E. coli isolates, 83.3% (10/12) were confirmed as extended-spectrum β-lactamase (ESBL)-producing strains. Gram-negative bacilli exhibited high-level resistance to ciprofloxacin (93.7%), ampicillin (100%), levofloxacin (87.5%), cefepime (68.7%), cefazolin (87.5%), cefuroxime (81.2%), and ceftriaxone (75.0%). Multivariable logistic regression identified age ≥ 60 years, double-J stent indwelling duration ≥ 30 days, daily fluid intake ≤ 2000 mL, serum albumin < 30 g/L, serum creatinine > 110 μmol/L, and glycated hemoglobin (HbA1c) > 6% as independent risk factors for biofilm-associated bacterial infection (p < 0.05).

CONCLUSION: When administered with equivalent dosing frequency (three doses total), FMT was associated with a significantly lower detection rate of biofilm-forming bacteria in double-J stent specimens compared with LFX among diabetic patients. These findings support the preferential use of FMT over LFX for targeted prophylaxis in high-risk diabetic populations and underscore the importance of integrating antimicrobial stewardship-particularly agent selection aligned with local resistance patterns-with proactive management of modifiable risk factors to optimize infection prevention and clinical outcomes.