Antibiotic treatment of asymptomatic urogenital infections in infertile couples is associated with improved sperm quality including sperm apoptosis parameters

Background: European Association of Urology (EAU) Guidelines identify urogenital infections as a possible treatable cause of infertility, yet the current recommendation for antibiotic treatment remains weak due to a lack of high-quality evidence. We evaluated the effect of antibiotic treatment of asymptomatic urogenital infections on both conventional and apoptosis-related (flow cytometry sperm apoptosis test, FACS-APO) sperm parameters, as well as on pregnancy outcomes, in infertile couples. Methods: In this retrospective, single-centre study, we analysed 265 couples with an asymptomatic urogenital infection (Ureaplasma urealyticum, Mycoplasma hominis, Mycoplasma genitalium, and Chlamydia trachomatis) confirmed in at least one partner by first-void urine testing, who received simultaneous antibiotic treatment. Paired conventional semen analysis and FACS-APO were performed before and 0-9 months after treatment completion. Partner infection concordance, the effect of follow-up timing on treatment response, and pregnancy outcomes within 12 months were also assessed. Results: Sperm concentration, total sperm count, total and progressive motility, and the proportion of viable sperm increased significantly after treatment, while the proportion of late apoptotic / necrotic sperm and calculated sperm DNA fragmentation decreased significantly (all p<0.05); the proportion of early apoptotic sperm remained unchanged, and semen volume did not change. Among 244 couples with complete bilateral microbiological testing, Ureaplasma urealyticum was by far the most prevalent pathogen (57.8% of men, 87.7% of women), and female partner positivity given male positivity was 83.0%. The improvement in sperm concentration and total sperm count was most pronounced within 3 months after treatment and diminished, or reversed, beyond 6 months. Pregnancy was achieved in 127 of 265 couples (47.9%; per-protocol rate 53.4%) within 12 months, most commonly following in vitro fertilization (72/127) or spontaneously (21/127). Conclusions: Antibiotic treatment of asymptomatic urogenital infections in infertile couples was associated with significant improvement in conventional semen parameters and a reduction in sperm apoptosis and calculated DNA fragmentation. Given the retrospective, uncontrolled design, these findings should be regarded as hypothesis-generating rather than definitive proof of a causal, fertility-enhancing effect, and warrant confirmation in prospective controlled studies.