Rectal infections with chlamydia and gonorrhoea in women attending a multiethnic sexually transmitted diseases urban clinic

Anorectal Neisseria gonorrhoeae infections in women with and without reported anal sex and sex workers in sexual health centres in the Netherlands: a retrospective cohort study

BACKGROUND

Control of Neisseria gonorrhoeae infection (gonorrhoea) depends on effective testing strategies. Anorectal testing in women is often done on indication of anal sex; however, anorectal infections are seen with and without anal exposure, possibly caused by autoinoculation. This study aims to enhance understanding of anorectal infections in women, by identifying risk factors for anorectal diagnosis.

METHODS

In this retrospective cohort study we used national surveillance data from Dutch sexual health centres from Jan 1, 2016, to Dec 31, 2021. We included cisgender women having sex with men who were tested urogenitally and anorectally for gonorrhoea. Due to different testing policies, we identified three groups: women who had not reported recent anal sex (in the past 6 months), women who had reported recent anal sex, and sex workers. Extracted data for analyses included demographics, sexual behaviour, and diagnosis of a sexually transmitted infection (STI). Per group, multivariable models using Firth's penalised maximum likelihood logistic regression were constructed, identifying determinants of anorectal gonorrhoea among all women and among gonorrhoea-positive women only. Variables included in model construction were age, education level, migration background, number of partners, condom use, partner notification, STI symptoms, having a partner who has sex with men (MSM) or a migrant partner, previous STI test, anal sex, and chlamydia and gonorrhoea diagnoses per anatomical location.

FINDINGS

In total, 117 693 women were included: 43 757 women without reported recent anal sex, 51 728 women with reported recent anal sex, and 22 208 sex workers. In all three groups, around 2% of women were gonorrhoea positive, and 70% or more of women had an anorectal infection. The strongest determinant of anorectal gonorrhoea was a concurrent urogenital gonorrhoea diagnosis (adjusted odds ratios [aOR] 782 [95% CI 605-1018]) among women without reported recent anal sex (612 [490-768] among women with reported recent anal sex, and 464 [335-652] among sex workers). Among gonorrhoea-positive women, determinants of anorectal gonorrhoea were urogenital and anorectal chlamydia co-infection (aOR 2·03 [95% CI 1·38-3·02], for women without reported anal sex) and migration background (1·44 [1·02-2·06], for women with reported anal sex). Determinants among sex workers were condomless sex (2·43 [1·55-3·82]), anal sex (1·71 [1·10-2·66]), MSM or migrant partner (1·78 [1·13-2·79]), and urogenital and anorectal chlamydia co-infection (2·28 [1·11-5·14]).

INTERPRETATION

These findings support the possibility of an autoinoculation process from the urogenital to the anorectal location due to the very strong correlation between urogenital and anorectal gonorrhoea, and due to the similarity of results across all three groups. Current testing strategies could miss anorectal infections, which should be considered when developing gonorrhoea prevention and control guidelines.

FUNDING

None.

Extragenital Sexually Transmitted Infection Testing Among Louisiana Parish Health Units, 2016-2019

BACKGROUND

The Centers for Disease Control and Prevention recommends that men who have sex with men (MSM) get tested annually for urethral and rectal chlamydia (CT) and gonorrhea (NG), and pharyngeal NG. There are no national recommendations to screen women and heterosexual men at extragenital sites. We assessed extragenital CT/NG screening among men and women at Louisiana's Parish Health Units (PHU).

METHODS

The Louisiana STD/HIV/Hepatitis Program piloted extragenital screening at 4 PHUs in February 2016 and expanded to 11 PHUs in 2017. Sexual histories were used to identify gender of sex partners and exposed sites. Because of billing restrictions, up to 2 anatomical sites were tested for CT/NG.

RESULTS

From February 2016 to June 2019, 70,895 urogenital and extragenital specimens (56,086 urogenital, 13,797 pharyngeal, and 1,012 rectal) were collected from 56,086 patients. Pharyngeal CT positivity was 160 of 7,868 (2.0%) among women, 54 of 4,838 (1.1%) among men who have sex with women (MSW) and 33 of 1,091 (3.0%) among MSM. Rectal CT positivity was 51 of 439 (11.6%) among women and 95 of 573 (16.6%) among MSM. Pharyngeal NG positivity was 299 of 7,868 (3.8%) among women, 222 of 4,838 (4.6%) among MSW, and 97 of 1,091 (8.9%) among MSM. Rectal NG positivity was 20 of 439 (4.6%) among women and 134 of 573 (23.4%) among MSM.Urogenital-only screening would have missed: among women, 173 of 3,923 (4.4%) CT and 227 of 1,480 (15.3%) NG infections; among MSW, 26 of 2,667 (1%) CT and 149 of 1,709 (8.7%) NG infections; and among MSM, 116 of 336 (34.5%) CT and 127 of 413 (42.1%) NG infections.

CONCLUSIONS

Many CT/NG infections would have been missed with urogenital-only screening. Men who have sex with men had much higher extragenital infection rates than women and MSW.

Trans-inclusive Sexual Health Questionnaire to Improve Human Immunodeficiency Virus/Sexually Transmitted Infection (STI) Care for Transgender Patients: Anatomic Site-Specific STI Prevalence and Screening

BACKGROUND

In 2018, the municipal Sexual Health Clinic in Seattle, implemented trans-inclusive questions about sexual behavior, anatomy, gender-affirming surgeries, and sexually transmitted infection (STI) symptoms in the clinic's computer-assisted self-interview (CASI) to improve care for transgender and nonbinary (TNB) patients.

METHODS

We calculated test positivity, the proportion of TNB patient visits that received testing for human immunodeficiency virus (HIV); syphilis; pharyngeal, rectal, and urogenital gonorrhea (GC); and chlamydia (CT) before (5/2016-12/2018) and after (12/2018-2/2020) implementation of new CASI questions, and the proportion of asymptomatic patients who received anatomic site-specific screening based on reported exposures.

RESULTS

There were 434 TNB patients with 489 and 337 clinic visits during each period, respectively. Nonbinary patients assigned male at birth (AMAB) had the highest prevalence of GC (10% pharyngeal, 14% rectal, 12% urogenital). Transgender women, transgender men, and nonbinary people AMAB had a high prevalence of rectal CT (10%, 9%, and 13%, respectively) and syphilis (9%, 5%, and 8%). Asymptomatic transgender women, transgender men, and nonbinary patients AMAB were more likely to receive extragenital GC/CT screening compared with nonbinary patients assigned female at birth. After implementation of trans-inclusive questions, there was a 33% increase in the number of annual TNB patient visits but no statistically significant increase in HIV/STI testing among TNB patients.

CONCLUSIONS

TNB people had a high prevalence of extragenital STIs and syphilis. Implementation of trans-inclusive medical history questions at a clinic that serves cisgender and transgender patients was feasible and important for improving the quality of affirming and inclusive sexual healthcare.

Metagenomic Shotgun Sequencing of Endocervical, Vaginal, and Rectal Samples among Fijian Women with and without Chlamydia trachomatis Reveals Disparate Microbial Populations and Function across Anatomic Sites: a Pilot Study

Chlamydia trachomatis is a sexually transmitted pathogen and a global public health concern. Little is known about the microbial composition and function across endocervical, vaginal, and rectal microbiomes in the context of C. trachomatis infection. We evaluated the microbiomes of 10 age-matched high-risk Fijian women with and without C. trachomatis using metagenomic shotgun sequencing (MSS). Lactobacillus iners and Lactobacillus crispatus dominated the vagina and endocervix of uninfected women. Species often found in higher relative abundance in bacterial vaginosis (BV)-Mageeibacillus indolicus, Prevotella spp., Sneathia spp., Gardnerella vaginalis, and Veillonellaceae spp.-were dominant in C. trachomatis-infected women. This combination of BV pathogens was unique to Pacific Islanders compared to previously studied groups. The C. trachomatis-infected endocervix had a higher diversity of microbiota and microbial profiles that were somewhat different from those of the vagina. However, community state type III (CST-III) and CST-IV predominated, reflecting pathogenic microbiota regardless of C. trachomatis infection status. Rectal microbiomes were dominated by Prevotella and Bacteroides, although four women had unique microbiomes with Gardnerella, Akkermansia, Bifidobacterium, and Brachyspira. A high level of microbial similarity across microbiomes in two C. trachomatis-infected women suggested intragenitorectal transmission. A number of metabolic pathways in the endocervix, driven by BV pathogens and C. trachomatis to meet nutritional requirements for survival/growth, 5-fold higher than that in the vagina indicated that endocervical microbial functions are likely more diverse and complex than those in the vagina. Our novel findings provide the impetus for larger prospective studies to interrogate microbial/microbiome interactions that promote C. trachomatis infection and better define the unique genitorectal microbiomes of Pacific Islanders. IMPORTANCE Chlamydia trachomatis is the primary cause of bacterial sexually transmitted infections worldwide, with a disturbing increase in annual rates. While there is a plethora of data on healthy and pathogenic vaginal microbiomes-defining microbial profiles and associations with sexually transmitted infections (STIs)-far fewer studies have similarly examined the endocervix or rectum. Further, vulnerable populations, such as Pacific Islanders, remain underrepresented in research. We investigated the microbial composition, structure, and function of these anatomic microbiomes using metagenomic shotgun sequencing among a Fijian cohort. We found, primarily among C. trachomatis-infected women, unique microbial profiles in endocervical, vaginal, and rectal microbiomes with an increased diversity and more complex microbial pathways in endocervical than vaginal microbiomes. Similarities in microbiome composition across sites for some women suggested intragenitorectal transmission. These novel insights into genitorectal microbiomes and their purported function require prospective studies to better define Pacific Islander microbiomes and microbial/microbiome interactions that promote C. trachomatis infection.

Promoting safer sex in the context of heterosexual anal intercourse: A scoping review

AIMS AND OBJECTIVES

To locate and summarise existing literature regarding safer sex practices specific to heterosexual anal intercourse and identify promising health promotion strategies.

BACKGROUND

Much of the literature regarding anal intercourse and safer sex is related to men who have sex with men. However, some studies suggest there are more women than men engaging in unprotected receptive anal intercourse. The risks associated with this sexual practice have been well documented, although many healthcare providers fail to ask about anal intercourse while addressing safer sex in the heterosexual population.

DESIGN

The study was based on Arksey and O'Malley's 2005 five-step methodology.

METHODS

A search was conducted of MEDLINE; CINAHL; PsycInfo; Cochrane; and PubMed. Databases were searched from 1990-2020. The 72 studies selected were classified according to their main area of focus. A grey literature search was also included. This scientific submission has been assessed for accuracy and completeness using the PRISMA-ScR guideline criteria (File S1).

RESULTS

The literature in this area is heterogeneous in terms of method and topic. Prevalence and incidence (n = 26) in addition to sexually transmitted infection risks (n = 26) related to heterosexual anal intercourse are well understood. However, there is limited information on condom use (n = 6), factors that influence heterosexual anal intercourse (n = 10) and health promotion strategies for this population and practice (n = 4). Two websites that mentioned heterosexual anal intercourse risk reduction activities were included.

CONCLUSIONS

Although heterosexual anal intercourse appears to be an increasingly common sexual practice, very little is known about health promotion strategies nurses might use for encouraging safer sex in this population.

RELEVANCE TO CLINICAL PRACTICE

Increased awareness of the prevalence and risks of heterosexual anal intercourse could enhance nurses' harm reduction strategies. Screening for sexually transmitted infections may be based on incorrect assumptions about sexual practices or due to stigma linked with anal intercourse. Reducing unprotected heterosexual anal intercourse will reduce sexually transmitted infections and their long-term sequelae.

Evidence supporting the standardisation of extragenital gonorrhoea and chlamydia screenings for women

OBJECTIVE

Current guidelines for women do not include extragenital screening for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) and do not mention anal sex behaviour. The objective of this cross-sectional study was to determine the number of potentially missed CT and NG cases by relying on urogenital screening and self-reported anal sex behaviour among women.

METHODS

Demographic and clinical data of 4658 women attending a community health centre in Los Angeles, California, USA from 2015 to 2018 were examined. CT and NG were detected using nucleic acid amplification test (APTIMA Combo 2, Hologic Gen-Probe, San Diego, California). Demographic and behavioural factors were also examined to assess potentially missed NG/CT cases. Multivariable regression analyses were used to determine whether reported anal sex behaviour predicts NG/CT rectal infection.

RESULTS

A total of 193 NG cases and 552 CT cases were identified; however, 53.9% of NG cases and 25.5% of CT cases were identified exclusively through extragenital screening. Of all positive cases of rectal CT, 87.0% did not report anal sex without a condom and 91.3% did not report any anal sex with their last sexual partner. Of all positive cases of rectal NG, 78.9% did not report anal sex without a condom and 76.3% did not report any anal sex with their last sexual partner. Anal sex with last partner was not predictive of NG/CT rectal infection.

CONCLUSIONS

Relying solely on urogenital screening and reported behaviour misses NG/CT cases. Extragenital NG/CT screening should be conducted in all women regardless of reported anal sex behaviour.

Infrequent Testing of Women for Rectal Chlamydia and Gonorrhea in the United States

Background

Anal sex is a common sexual behavior among women that increases their risk of acquiring rectal infection with Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC).

Methods

We estimated the frequency and positivity of rectal CT and GC tests for women aged 15-60 years performed by a large US commercial laboratory between November 2012 and September 2015. We also estimated the frequency and positivity of pharyngeal and genital specimens also performed on the same date. Among women with a positive CT or GC result, we estimated the frequency and positivity of recommended repeat testing within 12 months.

Results

Of 5499 women who had rectal CT and GC tests, positivity was 10.8%. On the same date, approximately 80% also had genital CT tests, genital GC tests, and pharyngeal GC tests, while 40% had pharyngeal CT tests. Rectal CT or GC infection was associated with genital CT or GC infection, but 46.5% of rectal CT and GC infections would not have been identified with genital testing alone. Among women with a rectal CT or GC infection, only 20.0% had a recommended repeat rectal test. Of those who had a repeat test, 17.7% were positive.

Conclusions

Testing women for rectal CT and GC was infrequent, but positive tests were often found in women with negative genital tests. Most women with positive rectal tests were not retested. Interventions are needed to increase extragenital CT and GC testing of at-risk women.

Rectal Chlamydia trachomatis and Neisseria gonorrhoeae Infections Among Women Reporting Anal Intercourse

OBJECTIVE

To examine the prevalence and treatment of rectal Chlamydia trachomatis and Neisseria gonorrhoeae infections among women reporting receptive anal intercourse in a network of sexually transmitted disease or sexual health clinics and estimate the proportion of missed infections if women were tested at the genital site only.

METHODS

We conducted a cross-sectional analysis of C trachomatis and N gonorrhoeae test results from female patients reporting receptive anal intercourse in the preceding 3 months during visits to 24 sexually transmitted disease clinics from 2015 to 2016. Primary outcomes of interest were 1) anatomic site-specific C trachomatis and N gonorrhoeae testing and positivity among women attending selected U.S. sexually transmitted disease clinics who reported receptive anal intercourse and 2) the proportion of rectal infections that would have remained undetected if only genital sites were tested.

RESULTS

Overall, 7.4% (3,743/50,785) of women reported receptive anal intercourse during the 2 years. Of the 2,818 women tested at both the genital and rectal sites for C trachomatis, 292 women were positive (61 genital only, 60 rectal only, and 171 at both sites). Of the 2,829 women tested at both the genital and rectal sites for N gonorrhoeae, 128 women were positive (31 genital only, 23 rectal only, and 74 at both sites). Among women tested at both anatomic sites, the proportion of missed C trachomatis infections would have been 20.5% and for N gonorrhoeae infections, 18.0%.

CONCLUSION

Genital testing alone misses approximately one fifth of C trachomatis and N gonorrhoeae infections in women reporting receptive anal intercourse in our study population. Missed rectal infections may result in ongoing transmission to other sexual partners and reinfection.

Factors associated with anorectal Chlamydia trachomatis or Neisseria gonorrhoeae test positivity in women: a systematic review and meta-analysis

OBJECTIVES

There has been considerable discussion about anorectal Chlamydia trachomatis (CT) in women, with some calling for anorectal CT screening, but little about anorectal Neisseria gonorrhoeae (NG). Given that urogenital NG is more strongly associated with pelvic inflammatory disease, this is an evidence gap. This systematic review and meta-analysis investigates the associations between anorectal CT in women and CT positivity at other sites (urogenital/oropharyngeal) and with anal intercourse, and compares these with anorectal NG within the same study populations.

METHODS

Electronic databases were searched for English-language studies published to October 2018 using the following terms: ("Chlamydia" OR "Chlamydia trachomatis") AND (("anal" OR "rect*" OR "anorect*") OR ("extra?genital" OR "multi?site")). Studies were included if anorectal NG data were available. Random-effects meta-analyses calculated pooled estimates; heterogeneity was investigated using meta-regression.

RESULTS

25 studies were eligible. Anorectal CT positivity ranged from 0% to 17.5%, with a summary estimate of 8.0% (95% CI 7.0 to 9.1; I2=88.5%). Anorectal NG positivity ranged from 0% to 17.0%, with a summary estimate of 2.1% (95% CI 1.6 to 2.8; I2=92.7%). The association between urogenital and anorectal positivity was stronger for NG than CT (summary prevalence ratio (PR)=89.3 (95% CI 53.1 to 150.3; I2=80.1%), PR=32.2 (95% CI 25.6 to 40.7; I2=70.3%), respectively), and between oropharyngeal and anorectal positivity it was stronger for NG than CT (PR=34.8 (95% CI 10.2 to 118.2; I2=89.9%), PR=8.8 (95% CI 6.8 to 11.5; I2=58.1%), respectively). Anal intercourse was associated with anorectal NG (PR=4.3; 95% CI 2.2 to 8.6; I2=0.0%) but not with anorectal CT (PR=1.0; 95% CI 0.7 to 1.4; I2=0.0%).

CONCLUSIONS

Anorectal CT is more common than anorectal NG, but anorectal NG is more strongly associated with anal intercourse, urogenital and oropharyngeal NG, suggesting that ongoing discussion about anorectal CT should also include NG. Longitudinal data are required to further understanding of the aetiology of anorectal STIs and assess whether anorectal screening is needed in women.

TRIAL REGISTRATION NUMBER

CRD42df017080188.

Sexually transmitted infections: Need for extragenital screening

Extragenital infections can occur concurrently with simultaneous urogenital infections. Extragenital sites are believed to serve as hidden reservoirs and play a critical role in their transmission. The etiological relationship of the most widespread Sexually transmitted diseases (STD) pathogen to reproductive tract has long been established, but the distribution to extragenital sites appears to be infrequent and its correlation with the sexual practice still requires to be investigated. Optimal-screening strategies for extragenital infections are largely unknown. However, there is a lack of data on clinical outcomes and optimal treatment regimens for rectal and pharyngeal extragenital infections. Further studies are needed in settings other than reproductive health and STD clinics, especially in primary care clinics and resource-limited settings.

Detection of Chlamydia trachomatis in rectal specimens in women and its association with anal intercourse: a systematic review and meta-analysis

OBJECTIVES

Chlamydia trachomatis is the most commonly diagnosed bacterial STI. Lack of prevalence and risk factor data for rectal chlamydia in women has testing and treatment implications, as azithromycin (a first-line urogenital chlamydia treatment) may be less effective for rectal chlamydia. We conducted a systematic review of studies on women in high-income countries to estimate rectal chlamydia prevalence, concurrency with urogenital chlamydia and associations with reported anal intercourse (AI).

DESIGN

Systematic review and four meta-analyses conducted using random-effects modelling.

DATA SOURCES

Medline, Embase, Cumulative Index to Nursing and Allied Health Literature, PsycINFO and the Cochrane Database were searched for articles published between January 1997 and October 2017.

ELIGIBILITY CRITERIA

Studies reporting rectal chlamydia positivity in heterosexual women aged ≥15 years old in high-income countries were included. Studies must have used nucleic acid amplification tests and reported both the total number of women tested for rectal chlamydia and the number of rectal chlamydia infections detected. Conference abstracts, case reports and studies with self-reported diagnoses were excluded. Data extracted included setting, rectal and urogenital chlamydia testing results, AI history, and demographics.

RESULTS

Fourteen eligible studies were identified, all among diverse populations attending sexual health services. Among routine clinic-attending women, summary rectal chlamydia positivity was 6.0% (95% CI 3.2% to 8.9%); summary concurrent rectal chlamydia infection was 68.1% in those who tested positive for urogenital chlamydia (95% CI 56.6% to 79.6%); and of those who tested negative for urogenital chlamydia, 2.2% (95% CI 0% to 5.2%) were positive for rectal chlamydia. Reported AI was not associated with rectal chlamydia (summary risk ratio 0.90; 95% CI 0.75 to 1.10).

CONCLUSIONS

High levels of rectal chlamydia infection have been shown in women with urogenital chlamydia infection. The absence of association between reported AI and rectal chlamydia suggests AI is not an adequate indicator for rectal testing. Further work is needed to determine policy and practice for routine rectal testing in women.

Patterns of Extragenital Chlamydia and Gonorrhea in Women and Men Who Have Sex With Men Reporting a History of Receptive Anal Intercourse

BACKGROUND

Screening for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) in men who have sex with men is risk based. Despite high frequencies of oral and receptive anal intercourse (RAI) among women, extragenital screening is not recommended.

METHODS

Women (n = 175) and men who have sex with men (n = 224) primarily recruited from a sexually transmitted infection clinic reporting a lifetime history of RAI completed a structured questionnaire and clinician-collected swab samples from the rectum, pharynx, vagina (women), and urine (men). CT and GC were detected using 2 commercial nucleic acid amplification tests (Aptima Combo 2; Hologic, Inc, Bedford, MA; Xpert CT/NG, Cepheid Innovation, Sunnyvale, CA).

RESULTS

The median age of the population was 26 years, 62% were white, and 88% were enrolled from a sexually transmitted disease clinic. Men were more likely than women to have GC (22.8% vs. 3.4%) and CT (21.9% vs. 12.6%). In men versus women, GC was detected in 16.5% versus 2.3% of pharyngeal swabs, 11.6% versus 2.3% of rectal swabs, and 5.4% versus 2.9% of urine samples or vaginal swabs. C. trachomatis was detected in 2.2% versus 1.7% of pharyngeal swabs, 17.4% versus 11.4% of rectal swabs, and 4.5% versus 10.3% for urogenital sites in men versus women. Overall 79.6% of CT and 76.5% of GC in men and 18.2% of CT and 16.7% of GC in women were detected only in the pharynx or rectum.

CONCLUSION

Reliance on urogenital screening alone misses most of GC and CT in men and more than 15% of infections in women reporting RAI.

Design of the FemCure study: prospective multicentre study on the transmission of genital and extra-genital Chlamydia trachomatis infections in women receiving routine care

Background

In women, anorectal infections with Chlamydia trachomatis (CT) are about as common as genital CT, yet the anorectal site remains largely untested in routine care. Anorectal CT frequently co-occurs with genital CT and may thus often be treated co-incidentally. Nevertheless, post-treatment detection of CT at both anatomic sites has been demonstrated. It is unknown whether anorectal CT may play a role in post-treatment transmission. This study, called FemCure, in women who receive routine treatment (either azithromycin or doxycycline) aims to understand the post-treatment transmission of anorectal CT infections, i.e., from their male sexual partner(s) and from and to the genital region of the same woman. The secondary objective is to evaluate other reasons for CT detection by nucleic acid amplification techniques (NAAT) such as treatment failure, in order to inform guidelines to optimize CT control.

Methods

A multicentre prospective cohort study (FemCure) is set up in which genital and/or anorectal CT positive women (n = 400) will be recruited at three large Dutch STI clinics located in South Limburg, Amsterdam and Rotterdam. The women self-collect anorectal and vaginal swabs before treatment, and at the end of weeks 1, 2, 4, 6, 8, 10, and 12. Samples are tested for presence of CT-DNA (by NAAT), load (by quantitative polymerase chain reaction -PCR), viability (by culture and viability PCR) and CT type (by multilocus sequence typing). Sexual exposure is assessed by online self-administered questionnaires and by testing samples for Y chromosomal DNA. Using logistic regression models, the impact of two key factors (i.e., sexual exposure and alternate anatomic site of infection) on detection of anorectal and genital CT will be assessed.

Discussion

The FemCure study will provide insight in the role of anorectal chlamydia infection in maintaining the CT burden in the context of treatment, and it will provide practical recommendations to reduce avoidable transmission. Implications will improve care strategies that take account of anorectal CT.

Trial registration

ClinicalTrials.gov Identifier: NCT02694497.

Rectal chlamydia - should screening be recommended in women?

Chlamydia trachomatis is the most common bacterial sexually transmitted infection in Europe and has large impacts on patients' physical and emotional health. Unidentified asymptomatic rectal Chlamydia trachomatis could be a partial explanation for the high Chlamydia trachomatis prevalence. In this study, we evaluated rectal Chlamydia trachomatis testing in relation to symptoms and sexual habits in women and men who have sex with men. Rectal Chlamydia trachomatis prevalence was 9.1% in women and 0.9% in men who have sex with men. None of the patients reported any rectal symptoms; 59.0% of the women with a rectal Chlamydia trachomatis infection denied anal intercourse and 18.8% did not have a urogenital infection; 9.4% did neither have a urogenital infection nor reported anal sex. We suggest that rectal sampling should be considered in women visiting sexually transmitted infection clinics regardless of rectal symptoms and irrespective of anal intercourse, since our data suggest that several cases of rectal Chlamydia trachomatis otherwise would be missed, thus enabling further disease transmission.

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.

High prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae infections in anal and pharyngeal sites among a community-based sample of men who have sex with men and transgender women in Lima, Peru

OBJECTIVES

This study aimed to characterise the epidemiology of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections among men who have sex with men (MSM) and transgender women (TW) in Lima, Peru.

SETTING

Cross-sectional study in Lima, Peru.

PARTICIPANTS

We recruited a group of 510 MSM and 208 TW for a subsequent community-based randomised controlled trial. The presence of CT and NG were evaluated using Aptima Combo2 in pharyngeal and anal swabs. We also explored correlates of these infections.

PRIMARY AND SECONDARY OUTCOME MEASURES

Study end points included overall prevalence of C. trachomatis and N. gonorrhoeae in anal and pharyngeal sites.

RESULTS

Overall prevalence of CT was 19% (95% CI 16.1% to 22.1%) and 4.8% (95% CI 3.3% to 6.6%) in anal and pharyngeal sites, respectively, while prevalence of NG was 9.6% (95% CI 7.5% to 12.0%) and 6.5% (95% CI 4.8% to 8.5%) in anal and pharyngeal sites, respectively.

CONCLUSIONS

The prevalence of each infection declined significantly among participants older than 34 years (p<0.05). Efforts towards prevention and treatment of extraurogenital chlamydial and gonococcal infections in high-risk populations like MSM and TW in Lima, Peru, are warranted.

TRIAL REGISTRATION NUMBER

NCT00670163; Results.

An Electronic Daily Diary Study of Anal Intercourse in Drug-Using Women

Women (N = 138) with histories of illicit drug use were recruited into an electronic diary study that used Android smartphones for data collection. The diary was to be completed each day for 12 weeks using an "app" created in HTML5 and accessed over the Internet via smartphone. Data collection included information on sexual behaviors with up to 10 partners per day and contextual factors surrounding sexual behavior such as drug use before/after, type of sexual behavior (oral, vaginal, anal), and other activities such as using condoms for vaginal and anal intercourse and use of sexual lubricants. The sample was predominantly African American (58 %); 20 % Latina, 20 % White and 2 % reported as Other. Most women reported either less than a high school education (33 %) or having a high school diploma (33 %). The mean age was 39 years (SD = 11.78). Anal intercourse occurred on days when women also reported using illicit drugs, specifically methamphetamine and cocaine. Anal intercourse was not an isolated sexual activity, but took place on days when vaginal intercourse and giving and receiving oral sex also occurred along with illicit drug use. Anal intercourse also occurred on days when women reported they wanted sex. HIV prevention interventions must address the risks of anal intercourse for women, taking into account concurrent drug use and sexual pleasure that may reduce individual harm-reduction behaviors.

What is needed to guide testing for anorectal and pharyngeal Chlamydia trachomatis and Neisseria gonorrhoeae in women and men? Evidence and opinion

Background

Anorectal and pharyngeal infections with Chlamydia trachomatis (CT) and Neisseria gonorrheae (NG) are commonly observed in men who have sex with men (MSM). There is increasing evidence that such infections at extra-genital sites are also common in women. In both sexes, these infections are largely overlooked as they are not routinely tested for in regular care. Testing based on sexual behavior or symptoms would only detect half of these extra-genital infections. This paper elucidates the differences and similarities between women and MSM, regarding the epidemiology of extra-genital CT and NG. It discusses the clinical and public health impact of untested extra-genital infections, how this may impact management strategies, and thereby identifies key research areas.

Discussion

Extra-genital CT is as common in women as it is in MSM; NG in women is as common at their extra-genital sites as it is at their genital sites. The substantial numbers of extra-genital CT and NG being missed in women and MSM indicate a need to test and treat more patients and perhaps different choices in treatment and partner management strategies. Doing so will likely contribute to reduced morbidity and transmission in both sexes. However, in our opinion, it is clear that there are several knowledge gaps in understanding the clinical and public health impact of extra-genital CT and NG. Key research areas that need to be addressed concern associated morbidity (anorectal and reproductive morbidity due to extra-genital infections), ‘the best’ management strategies, including testing and treatment for extra-genital CT, extra-genital treatment resistance, transmission probabilities between partners and between anatomic sites in a woman, and impact on transmission of other infections. Data are also lacking on cost-effectiveness of pharyngeal testing, and of NG testing and anorectal CT testing in women. Gaps in the management of extra-genital CT and NG may also apply for other STIs, such Mycoplasma genitalium.

Summary

Current management strategies, including testing, to address extra-genital CT and NG in both sexes are suboptimal. Comparative data on several identified key themes in women and MSM are lacking and urgently needed to guide better management of extra-genital infections.

Prevalence of and Factors Associated with Rectal-Only Chlamydia and Gonorrhoea in Women and in Men Who Have Sex with Men

BACKGROUND

Both anorectal Chlamydia trachomatis (CT) and Neisseria gonorrhoea (NG) can occur as a rectal-only infection or concurrently with simultaneous urogenital infection with the same pathogen. Characterising the target groups in which rectal-only infections occur may improve the efficacy of screening practices.

METHODS

We analysed data from two Dutch outpatient sexually transmitted infection (STI) clinics between 2011 and 2012. We included all men who have sex with men (MSM) (n = 9549) and women (n = 11113), ≥18 years, who had been tested for anorectal and urogenital CT and/or NG (either as a result of reporting anal sex/symptoms or via routine universal testing). Factors associated with rectal-only CT and NG infections were assessed using univariable and multivariable logistic regression.

RESULTS

In MSM, anorectal CT prevalence was 9.8% (693/7094), anorectal NG prevalence was 4.2% (397/9534). In women this was 9.5% overall (439/4597) and 0.9% (96/10972) respectively. Anorectal CT prevalence among women who were routinely universally tested was 10.4% (20/192), for selective testing this was 9.5% (419/4405) (p = 0.68). Anorectal NG infections were not detected among women who were routinely universally tested (p = 0.19). Among CT or NG positive MSM, rectal-only CT infections were found in 85.9% (595/693), for NG this was 85.6% (340/397) respectively. In positive women these figures were 22.1% (97/439)for CT and 20.8% (20/96) for NG, respectively. In MSM, independent factors associated with rectal-only CT were: being a sex worker (OR0.4,CI0.2-1.0), exclusively having sex with men (OR3.4,CI1.7-6.8), and absence of urogenital symptoms (OR0.2,CI0.2-0.4). In women, these factors were: older age (OR2.3, CI1.3-4.0) and non-Western nationality (OR1.8, CI1.0-3.5). Factors associated with rectal-only NG in MSM were: having been warned for STIs by an (ex) partner (OR2.9,CI1.1-7.5), oropharyngeal NG infection (OR2.4,CI1.0-5.3), and absence of urogenital symptoms (OR0.02,CI0.01-0.04), while in women no significant factors were identified.

CONCLUSIONS

The prevalence of anorectal CT and NG was substantial in MSM and prevalence of anorectal CT was also substantial in women. Anorectal infections occurred mostly as rectal-only infections in MSM and mostly concurrent with other infections in women. Given the lack of useful indicators for rectal-only infections, selective screening based on a priori patient characteristics will have low discriminatory power both in relation to MSM and women.

Neisseria gonorrhoeae and Chlamydia trachomatis among women reporting extragenital exposures

BACKGROUND

The Centers for Disease Control and Prevention recommends pharyngeal screening of Neisseria gonorrhoeae (GC) and rectal screening of GC and Chlamydia trachomatis (CT) in HIV-infected and at-risk men who have sex with men (MSM). There are currently no recommendations to routinely screen women at extragenital sites. We define the prevalence of extragenital GC and CT in women attending 2 urban sexually transmitted disease clinics in Baltimore City and compare it with the prevalence of extragenital infections in MSM and men who have sex with women.

METHODS

All patients who reported extragenital exposures in the preceding 3 months, who presented for care between June 1, 2011, and May 31, 2013, and who were tested for GC and CT using nucleic acid amplification tests at all sites of exposure were included in the analyses. We used logistic regression models to identify risk factors for extragenital infections.

RESULTS

A total of 10,389 patients were included in this analysis (88% African American; mean age, 29 years; 42% women; 7% MSM; 2.5% HIV infected). The prevalence estimates of any extragenital GC and CT were as follows: 2.4% GC and 3.7% CT in women, 2.6% GC and 1.6% CT in men who have sex with women, and 18.9% GC and 11.8% CT in MSM. Among women, 30.3% of GC infections and 13.8% of CT infections would have been missed with urogenital-only testing. Unlike MSM, age ≤ 18 years was the strongest predictor of extragenital infections in women.

CONCLUSIONS

Although the prevalence of extragenital gonorrhea and chlamydia is highest in MSM, a significant number of GC and CT infections in young women would be missed with genital-only testing. Cost-effectiveness analyses are needed to help inform national guidelines on extragenital screening in young women.

Anorectal Chlamydia trachomatis Load Is Similar in Men Who Have Sex with Men and Women Reporting Anal Sex

BACKGROUND

Anorectal Chlamydia trachomatis (chlamydia) is frequently diagnosed in men who have sex with men (MSM) and in women, but it is unknown whether these infections are comparable in clinical impact and transmission potential. Quantifying bacterial load and identifying determinants associated with high bacterial load could provide more insight.

METHODS

We selected a convenience sample of MSM who reported anal sex (n = 90) and women with concurrent urogenital/anorectal chlamydia who reported anal sex (n = 51) or did not report anal sex (n = 61) from the South Limburg Public Health Service's STI unit. Bacterial load (Chlamydia/ml) was quantified for all samples and log transformed for analyses. Samples with an unquantifiable human leukocyte antigen (n = 9) were excluded from analyses, as they were deemed inadequately sampled.

RESULTS

The mean log anorectal chlamydia load (3.50) was similar for MSM and women who reported having anal sex (3.80, P = 0.21). The anorectal chlamydia load was significantly higher in these groups than in women who did not report having anal sex (2.76, P = 0.001). Detectable load values ranged from 1.81-6.32 chlamydia/ml for MSM, 1.74-7.33 chlamydia/ml for women who reported having anal sex and 1.84-6.31 chlamydia/ml for women who did not report having anal sex. Symptoms and several other determinants were not associated with anorectal chlamydia load.

CONCLUSIONS

Women who did not report anal sex had lower anorectal loads, but they were within a similar range to the other two groups. Anorectal chlamydia load was comparable between MSM and women who reported anal sex, suggesting similar transmission potential.

Rectal chlamydia infection in women at high risk of chlamydia attending Canberra Sexual Health Centre

Chlamydia is the most commonly notified sexually transmitted infection in Australia. Australian guidelines recommend urogenital screening in asymptomatic men and women, and rectal screening in men who have sex with men or women reporting anal sex/symptoms. International studies describe a rectal chlamydia prevalence in women of 5% to 21%. We found that in women at high risk of chlamydia, 57% (32/56) tested positive for rectal chlamydia. Of these, 97% (31/32) had concurrent urogenital chlamydia. Women with urogenital chlamydia were significantly more likely to have a positive rectal result (χ(2), p = 0.000). Neither anal symptoms nor reported anal sex were associated with a positive rectal chlamydia test. The recommended treatment of rectal chlamydia differs substantially from that of urogenital chlamydia, raising the possibility that Australian women are being regularly undertreated due to a lack of rectal testing. Untreated rectal chlamydia may increase the risk of persistent infection, reproductive tract reinfection, complications and transmission. Further work is needed to determine the optimal management of chlamydia in women.

High prevalence of rectal gonorrhea and Chlamydia infection in women attending a sexually transmitted disease clinic

BACKGROUND

Testing women for urogenital Neisseria gonorrhoeae (GC) and Chlamydia trachomatis (CT) is common in sexually transmitted disease (STD) clinics. However, women may not be routinely tested for rectal GC/CT. This may lead to missed infections in women reporting anal intercourse (AI).

METHODS

This was a retrospective review of all women who underwent rectal GC/CT testing from August 2012 to June 2013 at an STD clinic in Columbus, Ohio. All women who reported AI in the last year had a rectal swab collected for GC/CT nucleic acid amplification testing (n=331). Using log-binomial regression models, we computed unadjusted and adjusted associations for demographic and behavioral factors associated with rectal GC/CT infection.

RESULTS

Participants (n=331) were 47% African-American, with median age of 29 years. Prevalence of rectal GC was 6%, rectal CT was 13%, and either rectal infection was 19%. Prevalence of urogenital GC and CT was 7% and 13% respectively. Among women with rectal GC, 14% tested negative for urogenital GC. Similarly, 14% of women with rectal CT tested negative for urogenital CT. In unadjusted analyses, there was increased rectal GC prevalence among women reporting sex in the last year with an injection drug user, with a person exchanging sex for drugs or money, with anonymous partners, and while intoxicated/high on alcohol or illicit drugs. After multivariable adjustment, no significant associations persisted, but a trend of increased rectal GC prevalence was observed for women <26 years of age (p=0.06) and those reporting sex while intoxicated/high on alcohol or drugs (p=0.05). For rectal CT, only age <26 years was associated with prevalent infection in unadjusted models; this association strengthened after multivariable adjustment (prevalence ratio: 6.03; 95% confidence interval: 2.29-15.90).

CONCLUSION

Nearly one in five women who reported AI in the last year had rectal GC or CT infection. Urogenital testing alone would have missed 14% of rectal infections. Standardized guidelines would increase rectal GC/CT testing in women and help detect missed infections.

Sexually transmitted infections among incarcerated women: findings from a decade of screening in a Los Angeles County Jail, 2002-2012

OBJECTIVES

We describe and report findings from a screening program to identify sexually transmitted infections (STIs) and HIV among female inmates in Los Angeles County Jail.

METHODS

Chlamydia and gonorrhea screening was offered to entering female inmates. Women were eligible if they were (1) aged 30 years or younger, or (2) pregnant or possibly pregnant, or (3) booked on prostitution or sex-related charges. Voluntary syphilis and HIV testing was offered to all women between 2006 and 2009. This analysis reports on data collected from 2002 through 2012.

RESULTS

A total of 76,207 women participated in the program. Chlamydia prevalence was 11.4% and gonorrhea was 3.1%. Early syphilis was identified in 1.4% (141 of 9733) and the overall prevalence of HIV was 1.1% (83 of 7448). Treatment levels for early syphilis and HIV were high (99% and 100%, respectively), but only 56% of chlamydia and 58% of gonorrhea cases were treated.

CONCLUSIONS

Screening incarcerated women in Los Angeles County revealed a high prevalence of STIs and HIV. These inmates represent a unique opportunity for the identification of STIs and HIV, although strategies to improve chlamydia and gonorrhea treatment rates are needed.

High co-occurrence of anorectal chlamydia with urogenital chlamydia in women visiting an STI clinic revealed by routine universal testing in an observational study; a recommendation towards a better anorectal chlamydia control in women

Background

Symptom- and sexual history-based testing i.e., testing on indication, for anorectal sexually transmitted infections (STIs) in women is common. Yet, it is unknown whether this strategy is effective. Moreover, little is known about alternative transmission routes i.e. by fingers/toys. This study assesses anorectal STI prevalence and infections missed by current testing practice, thereby informing the optimal control strategy for anorectal STIs in women.

Methods

Women (n = 663) attending our STI-clinic between May 2012-July 2013 were offered routine testing for anorectal and urogenital Chlamydia trachomatis and Neisseria gonorrhoeae. Data were collected on demographics, sexual behaviour and symptoms. Women were assigned to one of the categories: indication (reported anal sex/symptoms), fingers/toys (only reported use of fingers/toys), or without indication.

Results

Of women, 92% (n = 654) participated. There were 203 reports (31.0%) of anal sex and/or symptoms (indication), 48 reports (7.3%) of only using fingers/toys (fingers/toys), and 403 reports (61.6%) of no anal symptoms, no anal sex and no anal use of fingers/toys (without indication). The overall prevalence was 11.2% (73/654) for urogenital chlamydia and 8.4% (55/654) for anorectal chlamydia. Gonorrhoea infections were not observed. Prevalence of anorectal chlamydia was 7.9% (16/203) for women with indication and 8.6% (39/451) for all other women (P = 0.74). Two-thirds (39/55) of anorectal infections were diagnosed in women without indication. Isolated anorectal chlamydia was rare (n = 3): of all women with an anorectal infection, 94.5% (52/55) also had co-occurrence of urogenital chlamydia. Of all women with urogenital chlamydia, 71.2% (52/73) also had anorectal chlamydia.

Conclusions

Current selective testing on indication of symptoms and sexual history is not an appropriate control strategy for anorectal chlamydia in women visiting an STI clinic. Routine universal anorectal testing is feasible and may be a possible control strategy in women. Yet costs may be a problem. When more restricted control measures are preferred, possible alternatives include (1) anorectal testing only in women with urogenital chlamydia (problem: treatment delay or loss to follow up), and (2) direct treatment for urogenital chlamydia that is effective for anorectal chlamydia as well.

Female users of internet-based screening for rectal STIs: descriptive statistics and correlates of positivity

BACKGROUND

Internet-based screening for vaginal sexually transmitted infections (STI) has been shown to reach high-risk populations. Published studies of internet-based screening for rectal STIs in women are needed. Our objectives were to describe the female users of a rectal internet-based screening intervention and assess what factors correlated with rectal positivity for STIs.

METHODS

The website http://www.iwantthekit.org offers free STI testing via home self-sampling kits. Women could order vaginal and rectal kits, both containing questionnaires. Rectal and vaginal swabs were tested for Chlamydia trachomatis, Neisseria gonorrhoeae and Trichomonas vaginalis using nucleic acid amplification tests. Data were analysed from 205 rectal kits from January 2009 through February 2011. Self-reported characteristics of participants were examined, and correlates of rectal STI positivity were analysed.

RESULTS

Of the 205 rectal samples returned and eligible for testing, 38 (18.5%) were positive for at least one STI. The women were young (mean age 25.8 years), mostly African-American (50.0%), and only 14.0% always used condoms. After adjusting for age and race, Black race (AOR=3.06) and vaginal STI positivity (AOR=40.6) were significantly correlated with rectal STI positivity. Of women testing positive for rectal STIs who also submitted vaginal swabs, 29.4% were negative in the vaginal sample.

CONCLUSIONS

Internet-based rectal screening can reach populations that appear to be at high risk for rectal STIs (18.5% prevalence) and led to the diagnosis of STIs in women who would not have been diagnosed vaginally. Black race and vaginal STI positivity were highly correlated with rectal STI positivity.

Rectal Chlamydia in heterosexual women: more questions than answers

The aim of this study was to observe the proportion of concurrent rectal Chlamydia (RCt) infection in women who have cervical Chlamydia (CCt) and to observe whether there was any correlation with receptive anal intercourse (RAI). Untreated CCt-positive women were invited to take part. Women chose either to have a physician-collected or self-taken rectal swab. Treatment was then commenced. 17 samples were physician-collected and 80 were self-collected. 75/97 (77.3%, 95% Confidence Interval [95%CI] 69.0–85.7%) were RCt positive. 25/97 (25.8%, 95%CI 17.1–34.5%) reported RAI. There was no difference in the positivity rate whether RAI was reported (80%) or not (76%) ( P = 0.71); or whether swabs were physician-collected (65%) or self-taken (80%) ( P = 0.17). Only one of those with RCt reported rectal symptoms. One woman had concurrent gonococcal infection. 34/97 (35%) had a history of past sexually transmitted infections. Verified contact attendance was 0.52 and 72% of verified contacts were Chlamydia positive. Reported RAI may not be helpful in guiding RCt testing. RCt infection in women may be more prevalent than previously thought. We do not know whether RCt infections are clinically significant or whether they may act as a reservoir for re-infection. RCt infections in women require further study.

Cobas® 4800: a fully automated system for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae

Chlamydia trachomatis and Neisseria gonorrhoeae (CT/NG) are the most common sexually transmitted bacterial infections globally and account for the majority of the infections monitored by public health surveillance systems. Therefore, access to diagnostic tools that facilitate identification of these infections is critical to sexually transmitted infection control efforts. The cobas(®) 4800 system is a fully automated system that incorporates nucleic acid extraction and real-time PCR. The cobas 4800 CT/NG assay is one component of the test menu available on this system. The cobas 4800 CT/NG assay has excellent sensitivity and specificity as a result of dual primer targets, it utilizes self-obtained sample types, and is only one assay in a larger menu of tests that are performed on a system that is easy to use and maintain.

Invisible and at risk: STDs among young adult sexual minority women in the United States

CONTEXT

Sexual minority women are not adequately assessed by national STD surveillance systems, and research regarding STD burden in nationally representative samples of such women is rare. Moreover, few studies have assessed STD risk exclusively among young adult women.

METHODS

Wave 4 (2007-2008) data from the National Longitudinal Study of Adolescent Health on 7,296 females aged 24-32 were used to examine the relationship between sexual orientation and receipt of an STD diagnosis in the past year. Multivariate logistic regression analyses used two measures of sexual orientation: sexual identity and gender of sex partners.

RESULTS

Eighty percent of women considered themselves straight; 16% mostly straight; and 4% bisexual, mostly gay or gay. Eighty-five percent had had only male partners, while 7% had had one female partner, and 8% two or more female partners. In unadjusted models, women who identified themselves as mostly straight were more likely than straight women to have had an STD (odds ratio, 1.4); mostly gay or gay women were at lower risk (0.4). Women who had had two or more female partners had a higher STD risk than did women who had had only male partners (1.7). Adjusting for social and demographic characteristics did not substantially alter these results; however, the associations between sexual identity, gender of sex partners and STD diagnosis were eliminated after adjustment for sexual behaviors (e.g., having had anal sex).

CONCLUSIONS

Sexual identity, gender of sex partners and sexual behaviors should be taken into account in assessments of women's STD risk.

Prevalence and correlates of rectal Chlamydia and gonorrhea among female clients at sexually transmitted disease clinics

BACKGROUND

The prevalence and correlates of rectal sexually transmitted infections are well described among men who report receptive anal intercourse (AI); however, little is known about the epidemiology of rectal sexually transmitted infections among women.

METHODS

We conducted a cross-sectional study of women attending public sexually transmitted disease clinics in Los Angeles County, California. Women were eligible for inclusion in this study if they reported AI in the previous 90 days, were tested for rectal chlamydia and gonorrhea, and were seen between January 2008 and December 2010.

RESULTS

Among the 2084 clinic visits by women in this analysis, chlamydia and gonorrhea percent positivity by anatomic site was 12% (n = 144) for urogenital chlamydia, 14.6% (n = 171) for rectal chlamydia, 3.3% (n = 66) for urogenital gonorrhea, and 3.0% (n = 60) for rectal gonorrhea, with 25% of chlamydia cases and 19% of gonorrhea cases having rectal-only infections. Among women 25 years or younger, rectal infections were higher in visits in which women reported sex with an injection drug user (46.5% vs. 15.5%; P < 0.01) or sex with a HIV-positive partner (66.7% vs. 15.8%; P = 0.02). Among women older than 25 years, rectal infections were higher in visits where women reported substance use (10.6% vs. 5.8%; P ≤ 0.01). In multivariable models controlling for age and the presence of a urogenital infection, these associations remained.

CONCLUSIONS

Chlamydia and gonorrhea positivity was high among women reporting AI, and a large proportion of these cases would be missed in the absence of rectal testing. The high-risk behaviors of women with rectal infections highlight the need for rectal screening recommendations.

Population genomics of Chlamydia trachomatis: insights on drift, selection, recombination, and population structure

The large number of sexually transmitted diseases and ocular trachoma cases that are caused globally each year by Chlamydia trachomatis has made this organism a World Health Organization priority for vaccine development. However, there is no gene transfer system for Chlamydia to help identify potential vaccine targets. To accelerate discoveries toward this goal, here we analyzed the broadest diversity of C. trachomatis genomes to date, including 25 geographically dispersed clinical and seven reference strains representing 14 of the 19 known serotypes. Strikingly, all 32 genomes were found to have evidence of DNA acquisition by homologous recombination in their history. Four distinct clades were identified, which correspond to all C. trachomatis disease phenotypes: lymphogranuloma venereum (LGV; Clade 1); noninvasive urogenital infections (Clade 2); ocular trachoma (Clade 3); and protocolitis (Clade 4; also includes some noninvasive urogenital infections). Although the ancestral relationship between clades varied, most strains acted as donor and recipient of recombination with no evidence for barriers to genetic exchange. The niche-specific LGV and trachoma clades have undergone less recombination, although the opportunity for mixing with strains from other clades that infect the rectal and ocular mucosa, respectively, is evident. Furthermore, there are numerous occasions for gene conversion events through sequential infections at the same anatomic sites. The size of recombinant segments is relatively small (~357 bp) compared with in vitro experiments of various C. trachomatis strains but is consistent with in vitro estimates for other bacterial species including Escherichia coli and Helicobacter pylori. Selection has also played a crucial role during the diversification of the organism. Clade 2 had the lowest nonsynonymous to synonymous ratio (dN/dS) but the highest effect of recombination, which is consistent with the widespread occurrence of synonymous substitutions in recombined genomic segments. The trachoma Clade 3 had the highest dN/dS estimates, which may be caused by an increased effect of genetic drift from niche specialization and a reduced effective population size. The degree of drift, selection, and recombination in C. trachomatis suggests that the challenge will remain to identify genomic regions that are stable and cross protective for the development of an efficacious vaccine.