Rectal Chlamydia Research Articles

O002 Rates of asymptomatic lymphogranuloma venereum (LGV) in men who have sex with men (MSM)

Background/introduction The 2015 BASHH Chlamydia guidelines recommend LGV testing in asymptomatic HIV positive, but not HIV negative, MSM with rectal chlamydia. Despite evidence for serosorting among MSM having condomless sex, up to 16% are unaware of, or have different HIV status to their sex partners. HIV positive MSM may therefore transmit LGV to serodiscordent partners, resulting in higher than expected infection rates in HIV negative MSM. Aim(s)/objectives To compare rates of asymptomatic and symptomatic LGV in HIV positive and negative MSM attending a sexual health service. Methods Case notes of individuals with confirmed LGV from 8/6/2015–31/12/2015 were reviewed and data on demographics, symptoms, HIV status and presence of other STIs collected. Results We identified 105 cases of LGV (79% White; median age 35.3 years). 48 (46%) were HIV negative. 73% of HIV negative and 56% of HIV positive individuals were asymptomatic. 50 patients (47.7%) had one or more other STIs at time of initial LGV diagnosis; 62% were HIV positive. At time of censor, 95% of individuals attending for test of cure had a negative result. Discussion/conclusion Asymptomatic LGV was identified in 73% of HIV negative individuals which is likely to have been missed had they not been tested at initial chlamydia diagnosis. STIs facilitate onward transmission of HIV and our findings highlight the importance of continuing to recommend regular screening in all MSM regardless of HIV status to identify infections and offer timely treatment. We recommend LGV testing be extended to asymptomatic HIV negative MSM with rectal chlamydia.

P172 High HIV incidence in MSM diagnosed with early syphilis: a role for PrEP?

Background Understanding the risk factors for HIV acquisition allows targeted interventions to reduce HIV transmission such as PrEP. Aims/Objectives To evaluate HIV incidence in HIV-negative MSM with early syphilis infection. Methods A retrospective case-note review of MSM who were diagnosed with early syphilis between January and June 2014 at a London sexual health clinic. Results 206 MSM were diagnosed with early syphilis: 110 HIV-negative; 96 HIV-positive. For 110 HIV-negative MSM, median age was 32 y, median number of sexual partners in last 3 months was 4. Reported drug use in the previous month was 38%; 19% had injected drugs. Syphilis stage was primary (31%), secondary (25%), early latent (45%).Up to February 2016, total follow-up was 144 person-years. 12 (11%) were newly diagnosed HIV-positive. HIV incidence was 8.3 (95% confidence interval, CI 4.2–14) per 100 person-years follow-up (HPYFU). Incidence of rectal STIs was: rectal chlamydia, 27 HPYFU (CI 19–36); rectal gonorrhoea, 33 HPYFU (CI 25–44); syphilis re-infection, 10 HPYFU (CI 5.7–17). Conclusions The significant risk of HIV seroconversion following a diagnosis of early syphilis suggests that this group may particularly benefit from the use of pre-exposure prophylaxis. The high levels of subsequent rectal infections support the inclusion of regular STI screening in PrEP management guidelines.

P136 Is 7 days of doxycycline enough for the treatment of LGV?

Background Current treatment recommendations for lymphogranuloma venereum (LGV) are for 21 days of doxycycline but the evidence is limited. Aims To describe clinical outcomes in MSM treated with short-course doxycycline for rectal Chlamydia, subsequently proven to be LGV. Methods We reviewed all MSM who received 7–14 days of doxycycline but tested positive for LGV between Dec 2012 – Jan 2016. Clinical features and test of cure (TOC) results were tabulated. Results Thirty-three MSM with LGV were included. Median age was 35 (range 25–57), 88% were HIV positive and all tested positive for LGV-specific DNA in the rectum. Only 18/33 (55%) had ano-rectal symptoms including pain, bleeding, tenesmus, discharge, constipation, diarrhoea and ulceration. The remainder were asymptomatic or had genital symptoms. 24/33 (73%) were treated with 7 days of doxycycline, 8 (25%) with 14 days, and 1 patient received azithromycin 1g stat; 20 patients also received ceftriaxone 500mg. 100% (32/32) of patients treated with doxycycline had a negative TOC at a median 28 days (range 14–200). Of these, 1 patient had an initial positive rectal chlamydia TOC but this was LGV negative. The patient treated with azithromycin had a positive TOC at 24 days and remained symptomatic, representing treatment failure. Discussion/conclusion This case series suggests efficacy for short-course doxycycline for both symptomatic and asymptomatic rectal LGV with no treatment failures seen. Current BASHH Chlamydia guidelines suggest 21 days of doxycycline should be considered if no LGV test is done. Our data suggest this is not warranted but further prospective studies are needed.

P052 Men who have sex with men (MSM) presenting with repeat bacterial Sexually transmitted infections (STI) report high use of alcohol and party drugs

Background/introduction Bacterial sexually transmitted infections (Chlamydia, Gonorrhoea and Syphilis) are increasing in men who have sex with men in the UK. The reasons for this include alcohol and recreational drug use, availability of PrEP and awareness of HIV treatment as prevention, and social media. Aim(s)/objectives Our aim was to investigate the factors associated with recurrent bacterial STIs in MSM in Brighton, focusing specifically on drug and alcohol use. Methods We reviewed MSM presenting to our service between September 2014-September 2015 who had had 3 or more repeat attendances with a bacterial STI. We included infectious Syphilis, pharyngeal, rectal and urethral Chlamydia and Gonorrhoea. We collected data on alcohol and recreational drug use. Results An estimated 11,000 MSM attended during the study period. Of these, 46 MSM had 3 or more bacterial STIs. The median age was 34.5 years 21–57). 26/46 (57%) were HIV positive. 32/46 (70%) had 3 STIs; 10/46 (22%) had 4 STIs, 3/46 (7%) had 5 STIs and 1/46 (2%) had 6 STIs. 14/46 (30%) reported hazardous drinking, 31/46 (67%) reported use of party drugs (including Mephedrone, Crystal Meth, Ecstasy and GHB) and 7/46 (15%) reported ‘slamming’. Discussion/conclusion MSM attending multiple times with recurrent bacterial STIs also report high use of alcohol and recreational drug use including slamming. Public health interventions to reduce incidence of STIs should include focusing on drug and alcohol use in MSM.

P116 How Common is RectalChlamydia trachomatisInfection in Women? A Systematic Review, 1997 to 2015: Abstract P116 Table 1

Background Chlamydia trachomatis is the most commonly diagnosed STI in the UK. While men-who-have-sex-with-men are known to be at-risk of rectal chlamydia infection (ReCT), the prevalence and risk-factors in women are incompletely-understood. This may have important implications for testing and treatment approaches since azithromycin and doxycycline are considered first-line regimens for uncomplicated urogenital infections, whereas doxycycline is the preferred treatment for ReCT. Objectives Undertake a systematic review to: 1) calculate ReCT positivity (number ReCT positive/number tested) among women in different testing settings; 2) determine the proportion of women diagnosed with ReCT with: a) concurrent urogenital infections and; b) a history of anal-intercourse. Methods Medline, Embase, CINAHL, PsychINFO and the Cochrane Database were searched for articles published January 1997-September 2015. Studies reporting ReCT positivity in women aged ≥15 years in high-income countries were included and relevant data extracted. Results Fifteen studies were included (14 among women attending sexual health services). Populations tested varied e.g. 4/15 studies included only women with a history of anal-intercourse. Among all studies, ReCT positivity ranged from 0.5%–77% (median 13%). Among women with ReCT, 7%–100% had a concurrent urogenital infection; 16%–100% reported anal-intercourse (where data were available; Table 1) Conclusion ReCT infections have been found in a substantial proportion of women in the populations tested. In these studies, urogenital testing alone would have missed up to 31% of chlamydia infections. Further work to establish need, criteria and feasibility for routine ReCT testing in women is needed to ensure chlamydia infections are not missed or inadequately treated.

HIV Incidence and Predictors of Incident HIV among Men Who Have Sex with Men Attending a Sexual Health Clinic in Melbourne, Australia.

IntroductionThe aim of this study was to determine the risk factors for HIV infection and the incidence in men who have sex with men (MSM). It is important to identify subgroups of MSM in which preventive interventions such as pre-exposure prophylaxis (PrEP) offered at the time of their last negative test would be considered cost-effective.MethodsWe conducted a retrospective cohort study of MSM attending Melbourne Sexual Health Centre (MSHC) during 2007–2013 with at least two HIV tests within 12 months of each other. Demographic characteristics, sexual and other behaviours, and bacterial sexually transmitted infection (STI) diagnoses were extracted from the date of the last negative HIV test. HIV incidence rate (IR) per 100 person-years for each risk factor was calculated.ResultsOf the 13907 MSM who attended MSHC, 5256 MSM had at least two HIV tests and were eligible, contributing 6391 person-years follow-up. 81 new HIV diagnoses were identified within 12 months of an HIV negative test with an incidence of 1.3 (95% CI: 1.0–1.6) per 100 person-years. Significant associations with subsequent HIV infection were: rectal gonorrhea (HIV IR: 3.4 95% CI: 2.1–5.2), rectal chlamydia (HIV IR: 2.6 95% CI: 1.7–3.7), inconsistent condom use (HIV IR: 2.1 95% CI: 1.6–2.7), use of post-exposure prophylaxis (HIV IR: 2.3 95% CI: 1.7–3.1), and injecting drug use (HIV IR: 8.5 95% CI: 3.4–17.5).ConclusionThe incidence of HIV was above 2.0% in subgroups of MSM with specific characteristics at the last HIV negative test. PrEP is considered cost effective at this incidence and could potentially be used along with other preventive interventions for these individuals in more than half of the population.

Higher organism load associated with failure of azithromycin to treat rectal chlamydia.

Repeat rectal chlamydia infection is common in men who have sex with men (MSM) following treatment with 1 g azithromycin. This study describes the association between organism load and repeat rectal chlamydia infection, genovar distribution, and efficacy of azithromycin in asymptomatic MSM. Stored rectal chlamydia-positive samples from MSM were analysed for organism load and genotyped to assist differentiation between reinfection and treatment failure. Included men had follow-up tests within 100 days of index infection. Lymphogranuloma venereum and proctitis diagnosed symptomatically were excluded. Factors associated with repeat infection, treatment failure and reinfection were investigated. In total, 227 MSM were included - 64 with repeat infections [28·2%, 95% confidence interval (CI) 22·4-34·5]. Repeat positivity was associated with increased pre-treatment organism load [odds ratio (OR) 1·7, 95% CI 1·4-2·2]. Of 64 repeat infections, 29 (12·8%, 95% CI 8·7-17·8) were treatment failures and 35 (15·4%, 95% CI 11·0-20·8) were reinfections, 11 (17·2%, 95% CI 8·9-28·7) of which were definite reinfections. Treatment failure and reinfection were both associated with increased load (OR 2·0, 95% CI 1·4-2·7 and 1·6, 95% CI 1·2-2·2, respectively). The most prevalent genovars were G, D and J. Treatment efficacy for 1 g azithromycin was 83·6% (95% CI 77·2-88·8). Repeat positivity was associated with high pre-treatment organism load. Randomized controlled trials are urgently needed to evaluate azithromycin's efficacy and whether extended doses can overcome rectal infections with high organism load.

Characteristics Associated With Urethral and Rectal Gonorrhea and Chlamydia Diagnoses in a US National Sample of Gay and Bisexual Men: Results From the One Thousand Strong Panel.

Gay and bisexual men are at elevated risk for Neisseria gonorrhoeae and Chlamydia trachomatis (GC/CT). Rectal GC/CT symptoms may be less obvious than urethral, increasing opportunities for undiagnosed rectal GC/CT. A US national sample of 1071 gay and bisexual men completed urethral and rectal GC/CT testing and an online survey. In total, 6.2% were GC/CT positive (5.3% rectal, 1.7% urethral). We calculated adjusted (for education, race, age, relationship status, having health insurance, and income) odds ratios for factors associated with rectal and urethral GC/CT diagnoses. Age was inversely associated with urethral and rectal GC/CT. Compared with white men, Latinos had significantly greater odds of rectal GC/CT. Among men who reported anal sex, those reporting only insertive sex had lower odds of rectal GC/CT than did men who reported both insertive and receptive. There was a positive association between rectal GC/CT and number of male partners (<12 months), the number of anal receptive acts, receptive condomless anal sex (CAS) acts, and insertive CAS acts. Compared with those who had engaged in both insertive and receptive anal sex, those who engaged in only receptive anal sex had lower odds of urethral GC/CT. The number of male partners (<12 months) was associated with increased odds of urethral GC/CT. Rectal GC/CT was more common than urethral and associated with some demographic and behavioral characteristics. Our finding that insertive CAS acts was associated with rectal GC/CT highlights that providers should screen patients for GC/CT via a full range of transmission routes, lest GC/CT go undiagnosed.

A Retrospective Review of Treatment Failures Using Azithromycin and Doxycycline in the Treatment of Rectal Chlamydia Infections in Women and Men Who Have Sex With Men.

We examined the prevalence of rectal chlamydia treatment failures in men who have sex with men and women attending Alberta sexually transmitted infection clinics. Among those completing a test of cure, there was no significant difference among patients treated initially with azithromycin (treatment failure, 39/460 [8.5%]; 95% confidence interval, 5.9%-11.0%) compared with patients treated with doxycycline (0/16; 95% confidence interval, 0%-0.2%; P = 0.63).

Extragenital Infections Caused by Chlamydia trachomatis and Neisseria gonorrhoeae: A Review of the Literature.

In the United States, sexually transmitted diseases due to Chlamydia trachomatis and Neisseria gonorrhoeae continue to be a major public health burden. Screening of extragenital sites including the oropharynx and rectum is an emerging practice based on recent studies highlighting the prevalence of infection at these sites. We reviewed studies reporting the prevalence of extragenital infections in women, men who have sex with men (MSM), and men who have sex only with women (MSW), including distribution by anatomical site. Among women, prevalence was found to be 0.6–35.8% for rectal gonorrhea (median reported prevalence 1.9%), 0–29.6% for pharyngeal gonorrhea (median 2.1%), 2.0–77.3% for rectal chlamydia (median 8.7%), and 0.2–3.2% for pharyngeal chlamydia (median 1.7%). Among MSM, prevalence was found to be 0.2–24.0% for rectal gonorrhea (median 5.9%), 0.5–16.5% for pharyngeal gonorrhea (median 4.6%), 2.1–23.0% for rectal chlamydia (median 8.9%), and 0–3.6% for pharyngeal chlamydia (median 1.7%). Among MSW, the prevalence was found to be 0–5.7% for rectal gonorrhea (median 3.4%), 0.4–15.5% for pharyngeal gonorrhea (median 2.2%), 0–11.8% for rectal chlamydia (median 7.7%), and 0–22.0% for pharyngeal chlamydia (median 1.6%). Extragenital infections are often asymptomatic and found in the absence of reported risk behaviors, such as receptive anal and oral intercourse. We discuss current clinical recommendations and future directions for research.

An alternative model of sexually transmissible infection testing in men attending a sex-on-premises venue in Sydney: a cross-sectional descriptive study.

Background: Sydney Sexual Health Centre (SSHC) partnered with a large sex-on-premises venue, South Eastern Sydney Local Health District HIV and Related Programs Unit and AIDS Council of NSW (ACON) to develop and implement a community-based sexually transmissible infection (STI) screening model co-located in a sex-on-premises venue. This paper describes the process, the outcomes and examines the cost of this model. Methods: A retrospective cross-sectional study of gay and bisexual men (GBM) attending a STI testing service co-located in a sex-on-premises venue in Sydney city between the 1 November 2012 and 31 May 2014. Results: A total of 402 patrons had 499 testing episodes in the study period. Testing patrons were a median of 39.5 years of age, 221 (55%) were born overseas, 85 (21%) spoke a language other than English at home and 54 (13%) had a STI at first testing. A total of 105 (26%) testing patrons had never tested for a STI before. Of the 297 (74%) who had been tested before, 83 (21%) had not been tested within the last 12 months. A total of 77 STIs were detected in 63 people over 499 testing episodes, giving a STI positivity rate of 15% in the testing episodes. The prevalence of rectal chlamydia was the highest at 8% followed by pharyngeal gonorrhoea at 3%. A total of 97% of testing patrons were successfully relayed their results via their preferred methods within a median of 7.5 days. Conclusion: This paper highlights that offering STI screening in a community-based setting was an effective and low-cost alternative to traditional testing services.

What would be missed if we didn't screen men who have sex with men for oral chlamydia trachomatis? A cross-sectional study.

Background This study aimed to describe oropharyngeal chlamydia (OCT) in gay and bisexually active men (GBM) attending a large urban sexual health clinic in Sydney and determine what proportion of cases would be missed if screening was not routine. Retrospective data were extracted for all GBM with a positive OCT result between 1 October 2012 and 31 April 2014. The control group consisted of patients who had a negative OCT result on their first visit during the study period, and each patient was only counted once. A total of 74 of 2920 GBM (0.03, 95% CI: 0.02-0.03) were diagnosed with OCT. The 2920 GBM had a total of 11226 OCT tests performed, demonstrating OCT test positivity of 0.006 (95% CI: 0.005-0.008). A total of 62 sexually transmissible infections (STIs) were diagnosed at other sites: 34 rectal chlamydia (CT), 12 throat gonorrohea (GC), 7 urine CT, 7 rectal GC, 1 infectious syphilis and 1 non-gonoccal urethritis (NGU) case. Of the 74 OCT cases, 56 (0.76, 95% CI: 0.64-0.85) were treated with Azithromycin; 51 (69%) as part of standard treatment for their STI co-infection (34 rectal CT, 12 throat GC, 7 urine CT, 7 rectal GC, 1 NGU case) and a further five (7%) were treated as contacts. The remaining 18 people (0.24, 95% CI: 0.15-0.36) would not have been treated unless they were tested specifically for OCT. Overall, two-thirds of the OCT cases received appropriate treatment and only a small number of cases would have been missed had routine screening not been performed. With an extremely low overall test positivity of 0.6%, screening for OCT at our service adds little to population level health control.

Highly diverse MLVA-ompA genotypes of rectal Chlamydia trachomatis among men who have sex with men in Brighton, UK and evidence for an HIV-related sexual network

ObjectivesIn this prospective study, we aimed to determine the distribution of genotypes by multilocus variable number tandem repeat (VNTR) analysis plus analysis of the ompA gene (MLVA-ompA) of rectal Chlamydia...

Respondent-driven sampling among gay and bisexual men: experiences from a New Zealand pilot study.

BackgroundRespondent-driven sampling (RDS) is a method of approximating random sampling of populations that are difficult to locate and engage in research such as gay, bisexual and other men who have sex with men (GBM). However, its effectiveness among established urban gay communities in high-income countries is largely unexplored outside North America. We conducted a pilot study of RDS among urban GBM in Auckland, New Zealand to assess its local applicability for sexual health research.FindingsPre-fieldwork formative assessment explored RDS suitability among local GBM. Highly-networked initial participants (“seeds”) and subsequent participants completed a questionnaire, took a rectal swab for chlamydia and gonorrhoea testing, and were asked to recruit up to three eligible peers over the subsequent 2 weeks using study coupons. Compensation was given for participating and for each peer enrolled. Feedback on the pilot was obtained through questionnaire items, participant follow-up, and a focus group. Nine seeds commenced recruitment, directly enrolling 10 participants (Wave One), who in turn enrolled a further three (Wave Two). Two of the 22 participants (9 %) had undiagnosed rectal chlamydia. The coupon redemption rate (23 %) was lower than the expected rate (33 %) for this population. Participants were motivated by altruism above financial incentives; however, time, transport and reluctance recruiting peers were perceived as barriers to enrolment.DiscussionSlow recruitment in our pilot study suggests that RDS might not be an effective or efficient method of sampling gay men in all high-income urban settings. However those who participated in the pilot were willing to provide anal swabs and information on their sexual behaviour, and also on the size of their GBM social network which is necessary to weight data in RDS. Refinements and adaptations such as reducing the transaction costs of taking part (e.g. offering online participation) could improve responses but these have their own drawbacks (higher set-up costs, difficulty collecting biological specimens).

Pre-exposure prophylaxis to prevent the acquisition of HIV-1 infection (PROUD): effectiveness results from the pilot phase of a pragmatic open-label randomised trial

SummaryBackgroundRandomised placebo-controlled trials have shown that daily oral pre-exposure prophylaxis (PrEP) with tenofovir–emtricitabine reduces the risk of HIV infection. However, this benefit could be counteracted by risk compensation in users of PrEP. We did the PROUD study to assess this effect.MethodsPROUD is an open-label randomised trial done at 13 sexual health clinics in England. We enrolled HIV-negative gay and other men who have sex with men who had had anal intercourse without a condom in the previous 90 days. Participants were randomly assigned (1:1) to receive daily combined tenofovir disoproxil fumarate (245 mg) and emtricitabine (200 mg) either immediately or after a deferral period of 1 year. Randomisation was done via web-based access to a central computer-generated list with variable block sizes (stratified by clinical site). Follow-up was quarterly. The primary outcomes for the pilot phase were time to accrue 500 participants and retention; secondary outcomes included incident HIV infection during the deferral period, safety, adherence, and risk compensation. The trial is registered with ISRCTN (number ISRCTN94465371) and ClinicalTrials.gov (NCT02065986).FindingsWe enrolled 544 participants (275 in the immediate group, 269 in the deferred group) between Nov 29, 2012, and April 30, 2014. Based on early evidence of effectiveness, the trial steering committee recommended on Oct 13, 2014, that all deferred participants be offered PrEP. Follow-up for HIV incidence was complete for 243 (94%) of 259 patient-years in the immediate group versus 222 (90%) of 245 patient-years in the deferred group. Three HIV infections occurred in the immediate group (1·2/100 person-years) versus 20 in the deferred group (9·0/100 person-years) despite 174 prescriptions of post-exposure prophylaxis in the deferred group (relative reduction 86%, 90% CI 64–96, p=0·0001; absolute difference 7·8/100 person-years, 90% CI 4·3–11·3). 13 men (90% CI 9–23) in a similar population would need access to 1 year of PrEP to avert one HIV infection. We recorded no serious adverse drug reactions; 28 adverse events, most commonly nausea, headache, and arthralgia, resulted in interruption of PrEp. We detected no difference in the occurrence of sexually transmitted infections, including rectal gonorrhoea and chlamydia, between groups, despite a suggestion of risk compensation among some PrEP recipients.InterpretationIn this high incidence population, daily tenofovir–emtricitabine conferred even higher protection against HIV than in placebo-controlled trials, refuting concerns that effectiveness would be less in a real-world setting. There was no evidence of an increase in other sexually transmitted infections. Our findings strongly support the addition of PrEP to the standard of prevention for men who have sex with men at risk of HIV infection.FundingMRC Clinical Trials Unit at UCL, Public Health England, and Gilead Sciences.

003.1 Correlates of repeat anorectal infections among men who have sex with men

Introduction There is increasing concern about azithromycin treatment failure for rectal chlamydia. Higher organism loads have been reported at the rectal site compared to other sites (genital/oral) and higher organism load may be associated with treatment failure in women, but little data are available among men who have sex with men (MSM). This study examined the association between organism load and repeat rectal chlamydia infection in order to investigate possible mechanisms for treatment failure. Methods Stored rectal chlamydia positive samples from men attending Melbourne Sexual Health Centre between July 2008 to October 2013 were analysed for organism load and chlamydia serovar. Men were included if they had a follow-up test within 100 days of the index infection. Results There were 292 chlamydia positive index rectal swabs available for analysis. Organism load and serovar were assessable for 284 swabs -– 44 cases had one repeat positive result, 5 cases had two repeat positives and 181 MSM had a negative result within 100 days of their index positive result. Among the 230 index infections, 33% were serovar G, 30% were D, 15% were J, 9% were E, 7% were L2, 3% were B and 2% were F. The cumulative incidence of repeat rectal chlamydia within 100 days was 21%. Among those men who had a repeat positive result, all but three (3%) were the same serovar. Organism load was higher in index cases of men who had a repeat infection compared with those who did not (p Conclusion Repeat rectal chlamydia is common within 100 days among MSM attending MSHC. Most repeat infections were of the same serovar suggesting these infections were either treatment failure or re-infection from an infected partner. High organism load was associated with repeat infection suggesting a possible role in treatment failure. Disclosure of interest statement None.

LB1.4 Sti rates among gay men taking daily antiretrovirals for pre-exposure prophylaxis of hiv: the nsw demonstration project prelude

Introduction Pre-exposure prophylaxis (PrEP) prevents HIV infections but not other STIs. We assessed prevalence and incidence of STIs among PrEP users in the NSW demonstration study, PRELUDE. Methods By 14 July 2015, 268 gay and homosexually-identified men (GHM) were enrolled and started taking PrEP; 98 (36.6%) and 27 (10.1%) had reached three and six-month follow-up respectively. STI testing was conducted at baseline and quarterly follow-up visits. We calculated the baseline prevalence and incidence of STIs. The sample STI incidence will be compared with the population incidence in NSW. Results At enrolment, 17.2% of participants were diagnosed with ≥1 STI, including 10.8% with rectal gonorrhoea, rectal chlamydia and/or syphilis. The latter three STIs were diagnosed in 2.6%, 7.8%, and 1.1% of men, respectively. Among 98 men at 3-month follow-up, 17.3% were diagnosed with any of these STIs (3.1% had rectal gonorrhoea, 11.2% rectal chlamydia and 4.1% syphilis). At three months of follow-up, the incidence of these STIs was 18.4, 67.4 and 24.5 per 100 person-years (PY), respectively. By 14 July 2015, 27 PrEP users reached six months of follow-up. In this group, the incidence of rectal gonorrhoea was 29.6 per 100 PY (11.2% increase from month three follow-up, p Conclusion Among PrEP users in PRELUDE, the baseline prevalence and incidence of STIs were high and remained high in the early follow-up (indeed, the incidence of gonorrhoea has increased). Despite enrolment in a clinical study, with frequent follow-up, STI testing and treatment, PrEP users remain at very high risk of STIs. Longer follow-up is necessary to assess whether STI trends among PrEP users will change. The investigation of prophylaxis against other STIs and other methods of testing and treating STIs among these high-risk men appears to be warranted. Disclosure of interest statement The PRELUDE study is funded by the NSW Ministry of Health, with Gilead Sciences providing the study medication (Truvada).

O15.3 High chlamydia treatment failure rates in men who have sex with men

Introduction There is increasing concern about treatment failure among those treated for anogenital chlamydia infection. We used genotyping and survey data to differentiate between reinfection 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 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.

P09.17 Rectal infection withn. gonorrheaeand c. trachomatisin men in the united states

Background US guidelines recommend at least annual rectal chlamydia and gonorrhoea screening in men who have receptive anal intercourse. Data on rectal infection with chlamydia and gonorrhoea in men at the US national level are limited. Methods In an ongoing collaboration with LabCorp, a large commercial laboratory corporation with a substantial share of the US market, we estimated rectal chlamydia and gonorrhoea positivity in male rectal specimens tested in 2014. Rectal specimens have unique test codes that are consistent among all LabCorp laboratories. LabCorp had previously validated rectal specimens in collaborative studies. Results Of 38,411 rectal specimens for chlamydia or gonorrhoea, 96.8% (37,170) from 28,945 men aged 15–60 years were tested for both chlamydia and gonorrhoea with nucleic acid amplification tests (NAAT). Of these men, 90.0% had private insurance and 5.0% had Medicaid; 15.4% were aged 15–24 years, 36.4% 25–34 years, and 22.5% 35–44 years. Of these 37,170 specimens, 11.0% were positive for chlamydia, 8.3% gonorrhoea, and 2.4% both. Chlamydia and gonorrhoea positivity varied significantly (p 44 years, respectively). Of these specimens, 71.6% were collected by infectious disease doctors, 9.4% internists, 6.7% family doctors, and 2.6% public health providers. Conclusions This study represents the largest analysis of rectal testing for chlamydial and gonococcal infection in the US Almost all men who receive rectal testing are tested for both chlamydia and gonorrhoea; most rectal testing is performed by infectious disease doctors. NAATs are not FDA cleared for rectal specimens, but many clinical laboratories have validated NAATs under CLIA guidelines and can perform rectal testing. The LabCorp dataset might be the best available source for estimating male rectal infection with chlamydia and gonorrhoea.

Authors' Reply: Race and the Public Health Impact Potential of Pre-Exposure Prophylaxis in the United States.

Authors' Reply: Race and the Public Health Impact Potential of Pre-Exposure Prophylaxis in the United States.