NEW YORK (Reuters Health) – Increased sperm DNA fragmentation is observed in infertile men with genitourinary infection by Chlamydia trachomatis and Mycoplasma, according to a report in the August issue of Fertility and Sterility.

In laboratory studies, incubation of sperm with these microbes has been shown to decrease the percentage of motile sperm and to affect plasma membrane permeability, senior author Dr. Jose Luis Fernandez, from Complejo Hospitalario Universitario Juan Canalejo in Coruna, Spain, and colleagues note.

Although there has been evidence of increased sperm DNA fragmentation with Chlamydia and Mycoplasma infection, “a determination of the frequency of sperm cells containing fragmented DNA in sperm samples from infected males has to our knowledge not been reported,” the authors point out.

In the their investigation, the researchers assessed sperm DNA fragmentation as well as classical parameters, such as concentration and motility, in 143 infertile men infected with C. trachomatis and Mycoplasma and in 50 fertile controls. The impact of antibiotic therapy was assessed in 95 patients.

The proportion of sperm cells with fragmented DNA was 3.2-times higher in the infected group than in controls: 35.2% vs. 10.8%. A much smaller affect was noted on sperm concentration, motility, and morphology.

After antibiotic therapy for a mean of 3.8 months, the percentage of sperm cells with fragmented DNA dropped from 37.7% to 24.2%. By contrast, the researchers observed no improvement in sperm concentration or motility.

The pregnancy success rate during antibiotic therapy was just 12.5%. After completing therapy, however, the rate rose to 85.7%.

“Genitourinary infection by Chlamydia is the most common sexually transmitted infection” and its impact on sperm DNA could promote infertility, Dr. Fernandez told Reuters Health. Fortunately, “the infection is easily diagnosed and treatment is generally very effective. Screening of (infertile couples) is strongly recommended.”

Reference:
Fertil Steril 2008;90:328-334.