Impact of bacteriospermia on sperm DNA fragmentation: a narrative review

Male infertility remains a significant global challenge, with bacteriospermia increasingly recognized as a contributor to impaired reproductive function. Emerging evidence suggests that bacterial infections may induce sperm DNA fragmentation. This narrative review aimed to evaluate the impact of bacteriospermia on sperm DNA fragmentation and to identify the underlying biochemical mechanisms and clinical implications for subfertile men.

A comprehensive literature search was conducted across major databases, including PubMed/MEDLINE and Google Scholar, for studies published from 2008 to 2025. The search strategy employed keywords such as "DNA fragmentation", "bacteria", and "semen". Only peer-reviewed articles published in English were included to ensure data quality and relevance.

The prevalence of bacteriospermia varied by diagnostic method, ranging from 20.1-35.1% in polymerase chain reaction (PCR)-based assays and 15.28-34.88% in semen cultures. Regarding predominant strains, PCR tests most frequently identified Enterococcus faecalis, whereas culture methods primarily detected Enterococcus faecalis and Staphylococcus aureus. Three distinct large-scale studies have established a statistically significant correlation between general bacteriospermia and elevated levels of sperm DNA fragmentation. The primary mechanism for this damage is the induction of oxidative stress; bacterial presence triggers an excessive release of reactive oxygen species (ROS), which overwhelms seminal antioxidant defenses. This leads to lipid peroxidation of the sperm membrane-evidenced by elevated malondialdehyde levels-and subsequent DNA strand breaks.

Bacteriospermia might increase sperm DNA fragmentation significantly through oxidative stress, and well-designed prospective follow-up studies are warranted to further confirm these findings and establish definitive clinical protocols.