PCR for detection of Chlamydia trachomatis in endocervical, urethral, rectal, and pharyngeal swab samples obtained from patients attending an STD clinic

Detection of Rectal Chlamydia trachomatis in Heterosexual Men Who Report Cunnilingus

BACKGROUND

Rectal infection with Chlamydia trachomatis (CT) is frequent in women who deny receptive anal sex and is thought to arise from autoinoculation of the rectum from vaginal secretions. An alternate hypothesis is that oral sex inoculates and establishes gastrointestinal tract infection. Distinguishing these hypotheses is difficult in women. In men, autoinoculation is unlikely and heterosexual men frequently perform oral sex, but rarely participate in receptive anal exposure behaviors.

METHODS

We enrolled high-risk men with and without nongonococcal urethritis who presented to a sexually transmitted infection clinic in Indianapolis, Indiana. Urine and rectal swabs were collected and tested for urogenital and rectal CT, Neisseria gonorrhoeae (NG), and Mycoplasma genitalium (MG). Men completed surveys concerning symptoms, sexual orientation, and detailed recent and lifetime oral and anal sexual behaviors.

RESULTS

Rectal CT was detected in 2/84 (2.4%) heterosexual men who reported cunnilingus, but no lifetime receptive anal behaviors. All of the men who denied receptive anal behaviors were negative for rectal NG and MG. In homosexual and bisexual men, rectal CT prevalence was high (9.7%), and rectal NG (4.8%) and MG (4.8%) were also detected.

CONCLUSIONS

We detected rectal CT infections in heterosexual men who reported cunnilingus but denied receptive anal behaviors. Oral sex may be a risk factor for rectal CT infection via oral inoculation of the gastrointestinal tract.

What explains anorectal chlamydia infection in women? Implications of a mathematical model for test and treatment strategies

OBJECTIVES

Female anorectal Chlamydia trachomatis (chlamydia) infections are common irrespective of recent anal sex. We explored the role of anorectal infections in chlamydia transmission and estimated the impact of interventions aimed at improved detection and treatment of anorectal infections.

METHODS

We developed a pair compartmental model of heterosexuals aged 15-29 years attending STI clinics, in which women can be susceptible to or infected with chlamydia urogenitally and/or anorectally and men urogenitally. Transmission probabilities per vaginal and anal sex act, together with an autoinoculation probability, were estimated by fitting to anatomic site-specific prevalence data (14% urogenital; 11% anorectal prevalence). We investigated the 10-year reduction in female chlamydia prevalence of interventions (universal anorectal testing of female STI clinic attendees or doxycycline use for urogenital chlamydia) relative to continued current care (anorectal testing on indication and doxycycline for anorectal and azithromycin for urogenital chlamydia).

RESULTS

The transmission probability per anal sex act was 5.8% (IQR 3.0-8.3%), per vaginal sex act 2.0% (IQR 1.7-2.2%) and the daily autoinoculation probability was 0.7% (IQR 0.5-1.0%). More anorectal chlamydia infections were caused by autoinoculation than by recent anal sex. Universal anorectal testing reduced population prevalence modestly with 8.7% (IQR 7.6-9.7%), yet the reduction was double that of doxycycline use for urogenital infections (4.3% (IQR 3.5-5.3%)) relative to continued current care.

CONCLUSIONS

Autoinoculation between anatomic sites in women might play a role in sustaining high chlamydia prevalence. A shift to more anorectal testing of female STI clinic attendees may be considered for its (albeit modest) impact on reducing prevalence.

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.

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.

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.

Swab sample transfer for point-of-care diagnostics: characterization of swab types and manual agitation methods

BACKGROUND

The global need for disease detection and control has increased effort to engineer point-of-care (POC) tests that are simple, robust, affordable, and non-instrumented. In many POC tests, sample collection involves swabbing the site (e.g., nose, skin), agitating the swab in a fluid to release the sample, and transferring the fluid to a device for analysis. Poor performance in sample transfer can reduce sensitivity and reproducibility.

METHODS

In this study, we compared bacterial release efficiency of seven swab types using manual-agitation methods typical of POC devices. Transfer efficiency was measured using quantitative PCR (qPCR) for Staphylococcus aureus under conditions representing a range of sampling scenarios: 1) spiking low-volume samples onto the swab, 2) submerging the swab in excess-volume samples, and 3) swabbing dried sample from a surface.

RESULTS

Excess-volume samples gave the expected recovery for most swabs (based on tip fluid capacity); a polyurethane swab showed enhanced recovery, suggesting an ability to accumulate organisms during sampling. Dry samples led to recovery of ∼20-30% for all swabs tested, suggesting that swab structure and volume is less important when organisms are applied to the outer swab surface. Low-volume samples led to the widest range of transfer efficiencies between swab types. Rayon swabs (63 µL capacity) performed well for excess-volume samples, but showed poor recovery for low-volume samples. Nylon (100 µL) and polyester swabs (27 µL) showed intermediate recovery for low-volume and excess-volume samples. Polyurethane swabs (16 µL) showed excellent recovery for all sample types. This work demonstrates that swab transfer efficiency can be affected by swab material, structure, and fluid capacity and details of the sample. Results and quantitative analysis methods from this study will assist POC assay developers in selecting appropriate swab types and transfer methods.

Evaluation of sexual history-based screening of anatomic sites for chlamydia trachomatis and neisseria gonorrhoeae infection in men having sex with men in routine practice

Background

Sexually transmitted infection (STI) screening programmes are implemented in many countries to decrease burden of STI and to improve sexual health. Screening for Chlamydia trachomatis and Neisseria gonorrhoeae has a prominent role in these protocols. Most of the screening programmes concerning men having sex with men (MSM) are based on opportunistic urethral testing. In The Netherlands, a history-based approach is used. The aim of this study is to evaluate the protocol of screening anatomic sites for C. trachomatis and N. gonorrhoeae infection based on sexual history in MSM in routine practice in The Netherlands.

Methods

All MSM visiting the clinic for STI in The Hague are routinely asked about their sexual practice during consulting. As per protocol, tests for urogenital, oropharyngeal and anorectal infection are obtained based on reported site(s) of sexual contact. All consultations are entered into a database as part of the national STI monitoring system. Data of an 18 months period were retrieved from this database and analysed.

Results

A total of 1455 consultations in MSM were registered during the study period. The prevalence of C. trachomatis and N. gonorrhoeae per anatomic site was: urethral infection 4.0% respectively and 2.8%, oropharynx 1.5% and 4.2%, and anorectum 8.2% and 6.0%. The majority of chlamydia cases (72%) involved a single anatomic site, which was especially manifest for anorectal infections (79%), while 42% of gonorrhoea cases were single site. Twenty-six percent of MSM with anorectal chlamydia and 17% with anorectal gonorrhoea reported symptoms of proctitis; none of the oropharyngeal infections were symptomatic. Most cases of anorectal infection (83%) and oropharyngeal infection (100%) would have remained undiagnosed with a symptom-based protocol.

Conclusions

The current strategy of sexual-history based screening of multiple anatomic sites for chlamydia and gonorrhoea in MSM is a useful and valid guideline which is to be preferred over a symptom-based screening protocol.

Pilot study of COBAS PCR and ligase chain reaction for detection of rectal infections due to Chlamydia trachomatis

We tested rectal specimens from men who have sex with men for Chlamydia trachomatis by using COBAS PCR (Roche Diagnostics) and ligase chain reaction LCR (Abbott laboratories) and compared three PCR specimen-processing procedures. Chlamydiae were detected by one or more procedures in 22 of 186 specimens. All three PCR tests were positive for 17 specimens, all of which also tested positive by LCR.

Prevalence of chlamydia and gonorrhoea among a population of men who have sex with men

OBJECTIVES

Few data are available on the prevalence of sexually transmitted diseases (STDs) in men who have sex with men (MSM), making it difficult to develop STD screening guidelines for this population. The objective of the study was to determine the prevalence of urethral infections caused by Chlamydia trachomatis and Neisseria gonorrhoeae within a large, community based population of MSM, and to assess the feasibility of rectal screening in this population.

METHODS

This was a cross sectional study of 566 MSM, who were predominantly middle aged, white, asymptomatic, and engaged in sex with multiple partners. All provided a urine sample to screen for chlamydial and gonorrhoea infections using a PCR assay; rectal screening was performed on 48 participants.

RESULTS

Urethral C. trachomatis infections were detected in 1/566 participants (prevalence 0.2%, 95% CI 0.004% to 1.0%), and rectal C. trachomatis infections were detected in 2/48 men (prevalence 4.2%, 95% CI 0.5% to 14.2%). No gonorrhoea infections were detected, and none of the 117 HIV positive men had either infection.

CONCLUSIONS

Chlamydial and gonorrhoea infections were uncommon in this sample of MSM, even among those with multiple sexual partners or HIV infection. These data call into question recommendations to screen all MSM based on their individual sexual behaviours or HIV. Additional data are needed on the prevalence of these infections in MSM from different settings.

Comparison of a ligase chain reaction-based assay and cell culture for detection of pharyngeal carriage of Chlamydia trachomatis

In 264 genitourinary medicine clinic attenders reporting recent fellatio, the prevalence of pharyngeal Chlamydia trachomatis determined by an expanded standard including cell culture and two in-house PCR tests was 1.5% in 194 women and zero in 70 men. The ligase chain reaction (Abbott LCx) had a specificity of 99.2% and a positive predictive value of 60%.