O15.4 Azithromycin treatment failure in women infected with genital chlamydia infection

Abstract

and treatment failure among men who have sex with men (MSM), heterosexual men and women, diagnosed with repeat chlamydia infection within 1-4 months after treatment with azithromycin. Methods Participants completed an online survey capturing treatment and sexual behaviour data since initial diagnosis. Specimens from initial and repeat infections were included in the study. Chlamydia serovars were determined using quantitative PCR assays. When the same serovar was detected in both specimens for participants, MLST was used to further discriminate between genotypes. An algorithm based on genotype and sexual behaviour data was used to differentiate treatment failure from reinfection. Results There were 600 participants (200 MSM, 200 heterosexual males, 200 females) diagnosed with chlamydia. Of 301/600 who retested between 1-4 months: 258/301 (85.7%) were cured (treated and negative on retest); 4/301 (1.3%) had a definite reinfection (positive retest and different genotype); 19/301 (6.3%) had probable reinfection (positive retest, same genotype and reported unprotected sex with the same or a different partner); 17/301 (5.6%) had possible treatment failure (positive retest, same genotype and reported not having sex or always using condoms); 1/301 (0.3%) had a persistent infection (positive retest, same genotype and no documented treatment); and 2/301 (0.7%) could not be categorised due to insufficient information. Possible treatment failures were more common in MSM (11.3%, 12/106) vs other groups (2.6%, 5/195; p < 0.01). Among the possible treatment failures in MSM, 10/12 (83.3%) were initial rectal samples. Conclusion Treatment failure was common in MSM with rectal chlamydia, suggesting the need for treatment efficacy trials. Disclosure of interest statement No conflict of interest is declared.

The Effectiveness of Single-Dose Azithromycin Versus its Combination With Moxifloxacin Based on the Treatment of Chlamydial Cervicitis: A Study Protocol for a Randomized Clinical Trial

“…The sample size was determined as 100 using the following formula: where the percentage failure estimate in the treatment groups, as well as the odds ratio, the test significance level, and the test power are considered as follows based on previous studies (20,37): Further, the sample size was raised to 120 by taking account of potential attrition of 20%.…”