Chlamydia infection in males; an underappreciated problem

Abstract

Chlamydia is the most common bacterial STD worldwide. Most research focuses on female infections, however prevalence is similar in both males and females. Following intrapenile infection of mice prolonged infection occurred in the testis, in spermatogonial stem cells, spermatogonia and in residual bodies phagocytosed by Sertoli cells. Chlamydial infection also resulted in significant loss of epididymal sperm and damage to the epididymal epithelium, particularly in the cauda epididymis. Infected mice also had decreased sperm counts and motility, a significant decrease in morphologically normal sperm and increased sperm DNA damage. Similar epididymal and sperm damage was observed in Chlamydia-infected Koalas. Interestingly, when we infected vasectomised males there was no difference in chlamydial load in the testis, as detected by both culture and PCR, compared to intact control males. Following infection, Chlamydia-infected macrophages were detected in blood within 2–3 days of infection and tracking studies suggest that these cells are responsible for infection transmission to the testis. Adoptive transfer of immune CD4 cells prevented most of the damage seen in the testis suggesting that vaccination may be an effective means of preventing long-term damage to spermatogenesis and vaccine trials are currently underway in both mice and koalas. Thus chronic infection in the testis adversely affects many aspects of male fertility and represents an under-recognised problem.