Empirical Oral Antibiotic Therapy Is Associated with Reduced Sperm DNA Fragmentation in Infertile Men: A Retrospective Paired Pre- and Post-Intervention Study

Background/Objectives: This study aims to assess changes in seminal parameters and sperm DNA fragmentation (SDF) index after empirical oral antibiotic therapy in infertile men with baseline SDF index > 15%. Methods: This retrospective, paired, uncontrolled pre- and post-intervention study included 98 infertile men with elevated baseline SDF index. Semen samples were obtained before treatment and at least two months after simultaneous oral treatment with ciprofloxacin 1000 mg/day for 21 days and doxycycline 100 mg/day for 10 days. Semen volume, sperm concentration, total sperm count, progressive motility, sperm morphology, round cell concentration, and SDF index were assessed before and after treatment. Results: After treatment, conventional semen parameters did not change significantly. Round cell concentration decreased from 0.3 to 0.2 × 106/mL (p = 0.003), and median SDF index decreased from 30% to 20% (p < 0.0001). Conclusions: Empirical oral antibiotic therapy was associated with reductions in the SDF index and round cell concentration in this cohort. Because microbiological confirmation and an untreated control group were lacking, causality cannot be established, and controlled studies are required before routine clinical adoption.