Objective: Ureaplasma spp. comprise a group of mycoplasmas containing two human-associated species, namely, Ureaplasma urealyticum (UUR) and Ureaplasma parvum (UPA). The characterization of Ureaplasma species as pathogens contributing to male infertility remains a subject of considerable controversy. While numerous authors have proposed a relationship between UUR and changes in fertility, there is limited evidence supporting the involvement of UPA in this context. There has been an increased focus on Ureaplasma spp. and its potential role in the development of male infertility, especially over the past few years. The review aims to clarify the relationship between Ureaplasma species and male infertility.
Methods: Firstly, we introduce a background of the appropriate biology including growth characteristics, the divided biovars, and the transmission pathways. Secondly, we examine the studies that support a causal role for Ureaplasma spp. in the development of infertility in the last 30 years. Finally, the diagnosed method, antimicrobial susceptibility, and potential therapeutic considerations are evaluated.
Results: UPA and UUR can impair semen motility. The species of Ureaplasma spp., the sexual history of the patient, the number of sexual partners, the load of Ureaplasma, and antimicrobial resistance are expected to constitute key risk factors in the development of male infertility. In terms of treatment, Doxycycline remains the drug of first choice for ureaplasmal infections.
Conclusion: Ureaplasma spp. are not simply "innocent bystanders" in infertility and may indeed be an "underestimated enemy of human reproduction". Ureaplasma spp. can be considered an etiological agent in unexplained infertility and a useful marker.