Screening for rectal chlamydia infection in a genitourinary medicine clinic

Our department has been offering routine rectal chlamydia testing to all individuals reporting ano-receptive sex since 2002. We wanted to determine the prevalence of rectal chlamydia and if there were any factors associated with a positive diagnosis. A retrospective case-notes analysis was performed of all individuals tested for rectal chlamydia from November 2002 until March 2005. In total, 1187 case-notes were examined. Overall, the prevalence of chlamydia infection was 8.5%; in asymptomatic individuals, it was 5.1%. There was a positive association with chlamydia infection in patients who were HIV-positive, those who reported rectal symptoms and from samples in which microscopy of a rectal smear demonstrated >10 polymorphonuclear cells/high power field. The findings support our continuing to offer rectal chlamydia screening to patients attending our service. Chlamydia trachomatis infection should be considered as a possible diagnosis in patients who present with rectal symptoms outside a genitourinary medicine clinic setting.