The influence of Mycoplasma species on human and canine semen quality: a review

Mycoplasma species (spp.) are bacteria that are difficult to detect. Currently, the polymerase chain reaction (PCR) is considered the most effective diagnostic tool to detect these microorganisms in both human and veterinary medicine. There are 13 known species of human Mycoplasma and 15 species of canine Mycoplasma. Owing to the difficulties in identifying the individual species of Mycoplasma, there is a lack of information regarding which species are saprophytic and which are pathogenic. The prevalence of the individual species is also unknown. In addition, in both humans and dogs, the results of some studies on the impact of Mycoplasma are conflicting. The presence of Mycoplasma spp. on the epithelium of reproductive tract is often associated with infertility, although they are also detected in healthy individuals. The occurrence of Mycoplasma spp. is more common in dogs (even 89%) than in humans (1.3%-4%). This is probably because the pH of a dog's genital is more conducive to the growth of Mycoplasma spp. than that of humans. Phylogenetically, human and canine Mycoplasma are related, and majority of them belong to the same taxonomic group. Furthermore, 40% of canine Mycoplasma spp. are placed in common clusters with those of human. This suggests that species from the same cluster can play a similar role in the canine and human reproductive tracts. This review summarizes the current state of knowledge about the impact of Mycoplasma on canine and human male fertility as well as the prospects of further development in this field.

Automated summary

Mycoplasma spp. are difficult to detect bacteria, and PCR is the most effective diagnostic tool for detecting them. However, there is a lack of information about the pathogenicity and prevalence of different species. The impact of Mycoplasma on human and canine fertility is still controversial, but it is more common in dogs. Canine and human Mycoplasma are phylogenetically related and some species cluster together.