Aim: To investigate the alteration of some sperm proteins, anti-oxidants, and prostate-specific antigen in the seminal plasma of bacteriospermic infertile males.
 Study Design: The study is a case-control design to investigate the semen parameters and some sperm proteins in infertile males with bacteriospermia attending urology or fertility clinics in Port Harcourt, Rivers State, Nigeria.
 Place and Duration of Study: The study was carried out in the Department of Medical Laboratory Science, Rivers State University, Port Harcourt. However, some of the Laboratory investigations were done in the Chemical Pathology Unit and Medical Microbiology Unit of the University of Port Harcourt Teaching Hospital, Port Harcourt. The Study was between the period of September 2019 and Feb. 2022.
 Methodology: A total 193 subjects were recruited of which 76 were fertile without bacterial infection, 24 were fertile with bacterial infection, 37 infertile without bacterial infection and 56 infertile with bacterial infections. Infertile males were further classified as teratozoospermic, asthenoteratozoospermic, and oligoasthenoteratozoospermic. HSP70, PKA, MDA, TAC, and GPX (in seminal plasma), PSA, and testosterone (in serum) were analyzed using ELISA while TAC was done using spectrophotometric methods. Microbial culture was done to isolate and identify bacteria in semen. Results obtained were analyzed using GraphPad Prism and SPSS.
 Results: Culture results indicated that 52% of normospermic subjects had no semen infection at the time of the investigation. On the other hand, infertile male subjects without semen infections had 18.7%, while infertile males with semen infections were seen to be 29.2%. Likewise, subjects with bacteriospermia as scanty growth had 12.5%, 9.3% moderate, and 7.3% heavy growth. Significantly higher values of HSP70, PKA, PSA, and MDA were seen in infertile males with bacteriospermia compared with control and infertile males without infection while significantly lower values were seen in TAC, GPX, OPN, and testosterone were observed in the infertile males with bacteriospermia compared with control and infertile males without infection.
 Conclusion: Bacteriospermia significantly increased lipid peroxidation cum oxidative stress leading to altered physiological sperm proteins in the seminal plasma. These alterations could also be responsible for the poor sperm qualities observed in the infertile subjects.