Background/introduction We reported a significantly higher treatment failure rate with azithromycin for the treatment of rectal Chlamydia trachomatis (CT) when compared to doxycycline (26.2% vs. 0%, p = 0.0025). One-week 100 mg doxycycline twice daily was subsequently recommended as the local first-line treatment for rectal CT.

Aim(s)/objectives To re-evaluate the efficacy of doxycycline therapy in the treatment of rectal CT.

Methods Data was retrospectively collected on all patients diagnosed with rectal CT from 1^st October 2010 to 1^st October 2013 at a large, inner city sexual health clinic. Information was collected on gender, concurrent sexually transmitted infection (STI), treatment received, adherence to antibiotic, risk of re-infection and 4-week test of cure (TOC). Assessment of risk of re-infection included completion of telephone follow-up, verification of contact tracing of regular partners and absence of unprotected sexual intercourse.

Results 959 patients were diagnosed with rectal CT during the study period. 660 (68.8%) patients received doxycycline therapy in line with local treatment protocol. TOC was performed in 473 (71.7%) patients, of which 22 (4.7%) were positive. Risk of re-infection was excluded in 5 cases (22.7%) and considered possible treatment failures.

Discussion/conclusion The treatment failure rate of doxycycline for rectal CT identified in this study is similar to that reported with azithromycin and is contradictory to our previous findings. The longer study period with larger study population may explain this result. These findings suggest that TOC following treatment of rectal CT is necessary and would not support preferential use of doxycycline over azithromycin.