Molecular identification of viral and bacterial STD pathogens in infertile men in Northwestern Iran (2024–2025)

Male infertility is a multifactorial condition in which reproductive tract infections have been proposed as one of several possible contributing factors. Sexually transmitted pathogens have been associated with impaired semen quality in some populations. This study aimed to determine the prevalence of selected viral and bacterial sexually transmitted pathogens in semen samples obtained from infertile men in Northwestern Iran during 2024–2025. In this cross-sectional study, semen samples were collected from 150 infertile men aged 25–45 years who had visited the Ardabil Province Infertility Center. Semen analysis was performed according to the WHO (2021) guidelines. Genomic DNA was extracted using a commercial Qiagen kit, and DNA quality and concentration were assessed. PCR assays, incorporating a human β-globin internal amplification control, were used to detect C. trachomatis , N. gonorrhoeae , T. pallidum , HSV-2 , and HPV . PCR products were analyzed by 1.5% agarose gel electrophoresis. Serological screening for HIV, HBV, HCV , and syphilis was also performed. Descriptive statistical analyses were conducted. A total of 150 semen samples from infertile men were included in this study. Oligozoospermia was identified in 48 participants (32.0%), while asthenozoospermia was the most common semen abnormality, affecting 95 participants (63.3%). Abnormal sperm DNA was detected in only 2 cases (1.3%). PCR analysis of all semen samples showed no detectable Chlamydia trachomatis , Neisseria gonorrhoeae , Treponema pallidum , Herpes simplex virus ( HSV ), or Human papillomavirus ( HPV ). Amplification of the human β-globin internal control was successful in all samples, confirming adequate DNA quality and the absence of significant PCR inhibition. Serological testing demonstrated that all participants were negative for HIV , Hepatitis B virus ( HBV ), and syphilis, whereas anti- HCV antibodies were detected in 9 participants (6.0%). No evidence of the investigated sexually transmitted pathogens was detected in semen samples from infertile men included in this study. These findings should be interpreted in light of the descriptive study design, the absence of a fertile control group, and the limited pathogen panel. Further multicenter studies with larger sample sizes and broader pathogen screening are warranted to better characterize the prevalence of sexually transmitted infections among infertile men.