Objectives: To determine the prevalence of urethral and rectal Chlamydia trachomatis (CT) infection of lymphogranuloma venereum (LGV) and non-LGV associated serovars, in men who have sex with men (MSM).
Design: Multi-centre cross sectional survey.
Setting: Four genitourinary medicine clinics in the UK from 2006-7.
Subjects: 4825 urethral and 6778 rectal samples from consecutive MSM attending for sexual health screens.
Methods: Urethral swabs or urine and rectal swabs were tested for CT using a standard nucleic acid amplification tests. Chlamydia-positive specimens were sent to the reference laboratory for serovar determination.
Main Outcome: Positivity for both LGV and non-LGV associated CT serovars; proportion of cases that were symptomatic.
Results: The positivity (with 95% confidence intervals) in rectal samples was 6.06% (5.51, 6.66) for non-LGV CT, and 0.90% (0.69, 1.16) for LGV; for urethral samples 3.21% (2.74, 3.76) for non-LGV CT and 0.04% (0.01, 0.16) for LGV. The majority of LGV was symptomatic (95% of rectal, one of two urethral cases); non-LGV Chlamydia was mostly symptomatic in the urethra (68%) but not in the rectum (16%).
Conclusions: Chlamydial infections are common in MSM attending for sexual health screening, and the majority are non-LGV associated serovars. We did not identify a large reservoir of asymptomatic LGV in the rectum or urethra. Testing for Chlamydia from the rectum and urethra should be included for MSM requesting a sexual health screen, but serovar-typing is not indicated in the absence of symptoms. We have yet to identify the source of most cases of LGV in the UK.