Analysis of rectal Chlamydia trachomatis serovar distribution including L2 (lymphogranuloma venereum) at the Erasmus MC STI clinic, Rotterdam

Objectives: Compared to urogenital infections, little is known of serovar distribution in rectal chlamydial infection. The aim of this study was to explore possible relations between demographics, sexual behaviour, clinical manifestations, rectal symptoms, and chlamydial serovars including L2 (lymphogranuloma venereum). Methods: Genotyping was done prospectively in all rectal chlamydial infections since the outbreak of proctitis caused by lymphogranuloma venereum in February 2003. 33 (15.1%) rectal Chlamydia trachomatis infections from the years 2001 and 2002 were genotyped retrospectively. Results: Of all 219 rectal chlamydial infections, detected in the period July 2001 to August 2005, a total of 149 (68.0%) were successfully genotyped including 21 (14.1%) infections with serovar L2. In univariable and multivariable analyses, L2 serovar positive patients were significantly more often HIV positive (p = 0.002; OR: 6.5; 95% CI: 2.0 to 21.1), and had had sex in the past 6 months with more partners compared to other serovars. Furthermore, patients with L2 proctitis presented far more often with self reported rectal symptoms (p < 0.005; OR: 19.4; 95% CI: 4.9 to 77.0) and clinical manifestations (p < 0.005; OR: 15.4; 95% CI: 4.5 to 52.5). Conclusions: Chlamydial infections with serovar L2 show a different clinical and epidemiological pattern compared to serovar D-K. LGV proctitis is significantly associated with HIV positivity and a high number of sexual partners and causes more rectal symptoms and clinical manifestations. Neither young age nor ethnicity were identified as risk factors for any of the serovars investigated in this study.