Men who have sex with men (MSM) should receive routine rectal examinations for chlamydia, according to a study published in the online edition of Sexually Transmitted Infections as reported by aidsmap.com. Researchers found that more MSM respondents had rectal chlamydia than urethral chlamydia or rectal gonorrhea; in addition, more than one third of the men with rectal chlamydia were HIV positive.

According to the article, chlamydia is the most common bacterial sexually transmitted infection in the United Kingdom. While testing for urethral chlamydia is offered routinely to men attending sexual health clinics, those same facilities do not offer rectal testing for chlamydia, which causes changes to the genital mucosa and increases the risk for HIV transmission

“Current STI guidelines in the U.K. only recommend routine screening for rectal gonorrhea but not rectal chlamydia, and our data support the need to revisit these guidelines,” the researchers write. “We recommend routine screening for rectal chlamydia in men who have sex with men at risk of acquiring this infection.”