Chlamydia trachomatis in the pharynx and rectum of heterosexual patients at risk for genital infection

STI pathogens in the oropharynx: update on screening and treatment

PURPOSE OF REVIEW

The rise in antimicrobial resistance in several STI pathogens such as Neisseria gonorrhoeae has become a public health threat as only one first-line treatment remains. Reducing screening interval for gonorrhoea and chlamydia in high-prevalence populations has been proposed to address antimicrobial stewardship, but this remains controversial. This review aimed to revisit the epidemiology of infections at the oropharynx and review the current screening recommendations and treatment guidelines in different populations.

RECENT FINDINGS

Emerging evidence suggests that the oropharynx is the primary anatomical site for gonorrhoea transmission but maybe not for chlamydia transmission. Most international guidelines recommend 3-monthly oropharyngeal gonorrhoea and chlamydia screening for high-prevalence populations (e.g. men who have sex with men) but not low-prevalence populations (e.g. heterosexuals) given the clinical and public health benefits of screening in low-prevalence populations are still unclear. Doxycycline remains the first-line treatment for oropharyngeal chlamydia in most guidelines. However, some countries have moved from dual therapy (ceftriaxone and azithromycin) to monotherapy (ceftriaxone) for oropharyngeal gonorrhoea treatment to address antimicrobial stewardship.

SUMMARY

The transmission of gonorrhoea and chlamydia is still not fully understood. Further work will be required to evaluate the benefits and harms of reducing screening in high-prevalence populations.

Priorities and Progress in Diagnostic Research by the Antibacterial Resistance Leadership Group

The advancement of infectious disease diagnostics, along with studies devoted to infections caused by gram-negative and gram-positive bacteria, is a top scientific priority of the Antibacterial Resistance Leadership Group (ARLG). Diagnostic tests for infectious diseases are rapidly evolving and improving. However, the availability of rapid tests designed to determine antibacterial resistance or susceptibility directly in clinical specimens remains limited, especially for gram-negative organisms. Additionally, the clinical impact of many new tests, including an understanding of how best to use them to inform optimal antibiotic prescribing, remains to be defined. This review summarizes the recent work of the ARLG toward addressing these unmet needs in the diagnostics field and describes future directions for clinical research aimed at curbing the threat of antibiotic-resistant bacterial infections.

Chlamydia trachomatis conjunctivitis in the pre-pubertal child

Much is reported in the literature about the transmission and presentation of Chlamydia trachomatis conjunctival infection in the neonate; however, there is a paucity of information available on infection in the older pre-pubertal child (>3 years of age). We present the case of a 7-year-old girl, referred for assessment at the sexual assault referral centre following the diagnosis of unilateral C. trachomatis conjunctivitis. This child underwent a rigorous multiagency child protection process, with input from medical professionals, social services and the police to investigate the possibility of child sexual abuse (CSA). However, a group consensus was reached that non-sexual close contact transfer of C. trachomatis from the mother was the most likely mode of transmission and cause of infection. We aim to take the reader through the complex path to this conclusion, the approach to sexually transmitted infections and potential CSA and what is currently known about chlamydial conjunctivitis in children beyond the neonatal period.

Chlamydia trachomatis vaccine development - a view on the current challenges and how to move forward

INTRODUCTION

Chlamydia trachomatis is the most common sexually transmitted bacterial pathogen in the world. A licensed vaccine is not yet available, but the first vaccines have entered clinical trials.

AREAS COVERED

: We describe the progress that has been made in our understanding of the type of immunity that a protective vaccine should induce, and the challenges that vaccine developers face. We also focus on the clinical development of a chlamydia vaccine. The first chlamydia vaccine candidate has now been tested in a clinical phase-I trial, and another phase-I trial is currently running. We discuss what it will take to continue this development and what future trial setups could look like.

EXPERT OPINION

The chlamydia field is coming of age and the first phase I clinical trial of a C. trachomatis vaccine has been successfully completed. We expect and hope that this will motivate various stakeholders to support further development of chlamydia vaccines in humans.

High prevalence of rectal chlamydia among pregnant adolescents in La Romana, Dominican Republic warrants extragenital STI testing

To our knowledge, there are no studies estimating the prevalence of extragenital sexually transmitted infections (STIs) among pregnant adolescents in the Caribbean. This study sought to fill this gap by assessing the prevalence and correlates of oral, genital, and rectal chlamydia (CT) among a sample of pregnant adolescents in La Romana, Dominican Republic. Two hundred pregnant youths, aged 15-24 years, were recruited by systematic sampling during their first prenatal visit to a maternal care unit. A sociodemographic and behavioral questionnaire was administered and urine and oral/anal swabs were collected and tested for CT. Descriptive analyses and Fisher's exact tests were performed. The prevalence of oral, genital, and rectal CT was 6%, 15%, and 23%, respectively, although less than 5% of participants reported ever engaging in receptive anal intercourse. This discrepancy could be explained by autoinoculation, concurrent transmission during sex, undertreatment of rectal CT, or underreporting of anal sex. Almost half of CT infections would have been missed if only genital samples were collected, as current protocol dictates. More research is needed to understand sexual behaviors and rectal STI risk factors among heterosexual adolescent women. STI screening procedures for pregnant and sexually active adolescents should include routine testing of extragenital sites.

Simultaneous Evaluation of Diagnostic Assays for Pharyngeal and Rectal Neisseria gonorrhoeae and Chlamydia trachomatis Using a Master Protocol

Background

Pharyngeal and rectal Neisseria gonorrhoeae and Chlamydia trachomatis play important roles in infection and antibacterial resistance transmission, but no US Food and Drug Administration (FDA)–cleared assays for detection at these sites existed prior to this study. The objective was to estimate performance of assays to detect those infections in pharyngeal and rectal specimens to support regulatory submission.

Methods

We performed a cross-sectional, single-visit study of adults seeking sexually transmitted infection testing at 9 clinics in 7 states. We collected pharyngeal and rectal swabs from participants. The primary outcome was positive and negative percent agreement for detection of N. gonorrhoeae and C. trachomatis for 3 investigational assays compared to a composite reference. Secondary outcomes included positivity as well as positive and negative predictive values and likelihood ratios. Subgroup analyses included outcomes by symptom status and sex.

Results

A total of 2598 participants (79% male) underwent testing. We observed N. gonorrhoeae positivity of 8.1% in the pharynx and 7.9% in the rectum and C. trachomatis positivity of 2.0% in the pharynx and 8.7% in the rectum. Positive percent agreement ranged from 84.8% to 96.5% for different anatomic site infection combinations, whereas negative percent agreement was 98.8% to 99.6%.

Conclusions

This study utilized a Master Protocol to generate diagnostic performance data for multiple assays from different manufacturers in a single study population, which ultimately supported first-in-class FDA clearance for extragenital assays. We observed very good positive percent agreement when compared to a composite reference method for the detection of both pharyngeal and rectal N. gonorrhoeae and C. trachomatis.

Clinical Trials Registration

NCT02870101.

Chlamydia-Specific IgA Secretion in the Female Reproductive Tract Induced via Per-Oral Immunization Confers Protection against Primary Chlamydia Challenge

Chlamydia trachomatis is an obligate intracellular pathogen that causes sexually transmitted disease. In women, chlamydial infections may cause pelvic inflammatory disease (PID), ectopic pregnancy, and infertility. The role of antibodies in protection against a primary Chlamydia infection is unclear and was a focus of this work. Using the C. muridarum mouse infection model, we show that intestinal mucosa is infected via intranasal (i.n.) or per-oral (p.o.) Chlamydia inoculation and that unlike the female reproductive tract (FRT) mucosa, it halts systemic Chlamydia dissemination. Moreover, p.o. immunization or infection with Chlamydia confers protection against per-vaginal (p.v.) challenge, resulting in significantly decreased bacterial burden in the FRT, accelerated Chlamydia clearance, and reduced hydrosalpinx pathology. In contrast, subcutaneous (s.c.) immunization conferred no protection against the p.v. challenge. Both p.o. and s.c. immunizations induced Chlamydia-specific serum IgA. However, IgA was found only in the vaginal washes and fecal extracts of p.o.-immunized animals. Following a p.v. challenge, unimmunized control and s.c.-s.c.-immunized animals developed Chlamydia-specific intestinal IgA yet failed to develop IgA in the FRT, indicating that IgA response in the FRT relies on the FRT to gastrointestinal tract (GIT) antigen transport. Vaginal secretions of p.o.-immunized animals neutralize Chlamydia in vivo, resulting in significantly lower Chlamydia burden in the FRT and Chlamydia transport to the GIT. We also show that infection of the GIT is not necessary for induction of protective immunity in the FRT, a finding that is important for the development of p.o. subunit vaccines to target Chlamydia and possibly other sexually transmitted pathogens.

The role of saliva in gonorrhoea and chlamydia transmission to extragenital sites among men who have sex with men: new insights into transmission

INTRODUCTION

Gonorrhoea and chlamydia cases have been rising among gay, bisexual and other men who have sex with men (MSM) over the last decade. The majority of cases are extragenital and occur at the oropharynx and anorectum. The aim of this narrative review was to review the risk factors and mode of transmission for gonorrhoea and chlamydia at the oropharynx and anorectum among MSM.

RESULTS AND DISCUSSION

New evidence suggests that oropharyngeal gonorrhoea can be transmitted by kissing in addition to through the established route of condomless oral sex; and anorectal gonorrhoea can be acquired when saliva is used as a lubricant for anal sex and rimming in addition to the established route of condomless penile-anal sex in MSM. In contrast, condomless penile-anal sex remains the major route for chlamydia transmission.

CONCLUSIONS

Substantial transmission of gonorrhoea may occur with practices other than the established routes of condomless oral and/or anal sex and hence condoms may not be effective in preventing gonorrhoea transmission to extragenital sites. In contrast, condoms are effective for chlamydia control because it is mainly transmitted through condomless penile-anal sex. Novel interventions for gonorrhoea that reduce the risk of transmission at extragenital site are required.

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.

Diagnostic tests and specimens used to screen for Chlamydia trachomatis in genitourinary medicine clinics in the United Kingdom

This questionnaire study looked at the diagnostics tests and specimens used to screen for Chlamydia trachomatis in UK genitourinary medicine (GUM) clinics. Replies were received from 70% (185/265) of clinics. Half used only one site to screen women. One-third took anal swabs from patients who had anal sex and 10% took oropharyngeal swabs from patients who had oral sex.

Immunoassays were used to screen men for chlamydia in 86% of the clinics and women in 88%. Only 60% of male and 62% of female immunoassays were supplemented by a second test. Six per cent of clinics used molecular technique (MT) to screen men and 4% to screen women and 4% were trying to acquire it.

Culture was not available to 58% of clinics. MT was not available to 81%, 89% of which was due to non provision locally and/or cost. Only 7% of clinicians thought that using MT for screening was unnecessary. There were significant differences in the availability of the technique between large academic and small clinics. A national review of GUM strategies to screen for C. trachomatis with adequate funding is urgently needed.

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.

Chlamydial Antibiotic Resistance and Treatment Failure in Veterinary and Human Medicine

The Chlamydiaceae are widespread pathogens of both humans and animals. Chlamydia trachomatis infection causes blinding trachoma and reproductive complications in humans. Chlamydia pneumoniae causes human respiratory tract infections and atypical pneumonia. Chlamydia suis infection is associated with conjunctivitis, diarrhea, and failure to gain weight in domestic swine. Chlamydial infections in humans and domesticated animals are generally controlled by antibiotic treatment—particularly macrolides (usually azithromycin) and tetracyclines (tetracycline and doxycycline). Tetracycline-containing feed has also been used to limit infections and promote growth in livestock populations, although its use has decreased because of growing concerns about antimicrobial resistance development. Because Sandoz and Rockey published an elegant review of chlamydial anti-microbial resistance in 2010, we will review the following: (i) antibiotic resistance in C. suis, (ii) recent evidence for acquired resistance in human chlamydial infections, and (iii) recent non-genetic mechanisms of antibiotic resistance that may contribute to treatment failure.

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.

Transmission heterogeneity and autoinoculation in a multisite infection model of HPV

The human papillomavirus (HPV) is sexually transmitted and can infect oral, genital, and anal sites in the human epithelium. Here, we develop a multisite transmission model that includes autoinoculation to study HPV and other multisite diseases. Under a homogeneous-contacts assumption, we analyze the basic reproduction number R0, as well as type and target reproduction numbers, for a two-site model. In particular, we find that R0 occupies a space between taking the maximum of next generation matrix terms for same site transmission and taking the geometric average of cross-site transmission terms in such a way that heterogeneity in the same-site transmission rates increases R0 while heterogeneity in the cross-site transmission decreases it. Additionally, autoinoculation adds considerable complexity to the form of R0. We extend this analysis to a heterosexual population, which additionally yields dynamics analogous to those of vector-host models. We also examine how these issues of heterogeneity may affect disease control, using type and target reproduction numbers.

Comparison of doxycycline with azithromycin in treatment of pharyngeal chlamydia infection

Recent data suggest that azithromycin may not be as effective as doxycycline in eradication of genital chlamydial infection. The aim of this study was to compare the eradication rate of pharyngeal Chlamydia trachomatis infection after treatment with azithromycin 1 g stat with that of doxycycline 100 mg twice a day for seven days. A prospective open-label observational study was conducted on patients with pharyngeal Chlamydia trachomatis diagnosed at Whittall Street Clinic, University Hospitals Birmingham, Birmingham, UK, between July 2012 and July 2013. We confirmed eradication of pharyngeal Chlamydia trachomatis with a negative test of cure. We treated all our patients with azithromycin 1 g stat until February 2013. At that stage, we offered doxycycline to patients with pharyngeal Chlamydia trachomatis A total of 398 patients (52 men, 346 women) were diagnosed with pharyngeal Chlamydia trachomatis during the study period. Of the 172 patients included in the final analysis, 78 were treated with azithromycin and 64 with doxycycline. Treatment failure was identified among 8/78 (10%) patients treated with azithromycin and 1/64 (2%) treated with doxycycline (absolute difference: 8 percentage points, 95% CI: 0-17%, p = 0.041). In our study, doxycycline 100 mg twice a day for seven days was associated with less treatment failure of oropharyngeal chlamydia compared with azithromycin 1 g stat Future randomised studies should investigate whether patients with pharyngeal Chlamydia trachomatis should be followed up with a test of cure when treated with azithromycin, or be treated with doxycycline.

Incidence of gonococcal and chlamydial infections and coverage of two laboratory surveillance networks, France, 2012

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Evaluation of the Versant CT/GC DNA 1.0 assay (kPCR) for the detection of extra-genital Chlamydia trachomatis and Neisseria gonorrhoeae infections

Screening for extra-genital Chlamydia trachomatis and Neisseria gonorrhoeae infections is a crucial component for sexually transmitted diseases management, even if at present days no commercial methods have been approved for use on pharyngeal and rectal specimens by the US FDA or have received the conformity CE marking. Here we report the analytical sensitivities of the Versant CT/GC 1.0 assay (Siemens Healthcare Diagnostics, Tarrytown, NY, USA) on rectal and pharyngeal swabs, and an evaluation about the suitability for this assay with two widely used swab collection devices (E-Swab and eNAT, Copan, Brescia, Italy). The limits of detection for rectal and pharyngeal specimens with the Versant assay were 10 copies/ml and 1.0 copies/ml, for C. trachomatis and N. gonorrhoeae, respectively. False positive results due to the presence of non-gonococcal Neisseria species were excluded when clinical rectal and pharyngeal samples containing organisms identified as N. meningitidis, N. sicca, N. flavescens and N. subflava were tested. Due to its sensitivity and specificity, the Versant assay represents a good choice for the diagnosis of chlamydial and/or gonococcal infections not only in genito-urinary samples, but also on rectal and pharyngeal swabs.

Spontaneous pharyngeal Chlamydia trachomatis RNA clearance. A cross-sectional study followed by a cohort study of untreated STI clinic patients in Amsterdam, The Netherlands

OBJECTIVES

Pharyngeal Chlamydia trachomatis (chlamydia) might contribute to ongoing chlamydia transmission, yet data on spontaneous clearance duration are rare. We examined the prevalence, spontaneous clearance, chlamydial DNA concentration and genotypes of pharyngeal chlamydia among clinic patients with sexually transmitted infection (STI).

METHODS

Female patients at high risk for an STI who reported active oral sex and male patients who have sex with men (MSM) were screened for pharyngeal chlamydia RNA using a nucleic acid amplification test. A repeat swab was obtained to evaluate spontaneous clearance in untreated patients with pharyngeal chlamydia. Quantitative chlamydia DNA load was determined by calculating the chlamydia/human cell ratio.

RESULTS

Pharyngeal chlamydia was detected in 148/13 111 (1.1%) MSM and in 160/6915 (2.3%) women. 53% of MSM and 32% of women with pharyngeal chlamydia did not have a concurrent anogenital chlamydia infection. In 16/43 (37%) MSM and in 20/55 (36%) women, the repeat pharyngeal swab was negative (median follow-up 10 days, range 4-58 days). Patients with an initial chlamydial DNA concentration above the median were less likely to clear. Of 23 MSM with pharyngeal chlamydia who had sex with a lymphogranuloma venereum (LGV)-positive partner recently or in the past, two were LGV biovar positive (8.7%).

CONCLUSIONS

The pharynx is a reservoir for chlamydia and LGV, and may play a role in ongoing transmission. Although delay in ribosomal RNA decline after resolution of the infection might have led to an underestimation of spontaneous clearance, in high-risk STI clinic patients, testing the pharynx for chlamydia should be considered.

What's in a word: the use, misuse, and abuse of the word "persistence" in Chlamydia biology

The word persistence was used by Chlamydia researchers almost as soon as Chlamydia research was born to reflect the propensity of chlamydiae to cause inapparent infection in their hosts, from birds to humans. More recently, the term persistence has been used, misused, and sometimes abused amidst in vitro and in vivo studies that aim to mimick the ability of chlamydiae to emerge from the presumed inapparent state into clinically detectable infection and disease. Here, I have attempted to provide a global perspective on the state of research on chlamydial persistence, revisiting old observations that may warrant a new look, critically evaluating more recent observations and their shortcomings, and including recent developments that may help redefine chlamydiae as pathogens-or not-of both animals and humans.

Hidden in plain sight: chlamydial gastrointestinal infection and its relevance to persistence in human genital infection

Although the concept of persistence in chlamydial infections has been recognized for about 80 years, there is still very little known about the mechanism by which this occurs. In this review, we revisit an old paradigm, long known to chlamydiologists and veterinarians, that in virtually all hosts of chlamydiae, including mammals and birds, chlamydiae reside in the gastrointestinal tract for long periods of time in the absence of clinical disease. Thus, if gastrointestinal infection occurs in most hosts, then it is very likely that gastrointestinal infection occurs in humans as well. We demonstrate that gastrointestinal infection does indeed occur in humans and propose that this anatomical site is the source of persistent infection in humans. The data in ruminants and animal models demonstrate that the immune system is unable to clear chlamydiae from the gut, so they can remain indefinitely, with continual shedding in feces. Clearly, many women become reinfected from an untreated partner; however, we propose that women, cured of genital infection, remain at risk for autoinoculation from the lower gastrointestinal tract. Moreover, there are substantial data demonstrating treatment failure of chlamydial infections, particularly with azithromycin. New data in the mouse model have shown that azithromycin is far less effective against chlamydial gastrointestinal infection than against genital infections. Therefore, it is possible that women cured of genital infection by antibiotics remain infected in the gastrointestinal tract and can become reinfected by autoinoculation from that site.

Differential susceptibilities to azithromycin treatment of chlamydial infection in the gastrointestinal tract and cervix

Evidence from animal studies suggests that chlamydiae may persist in the gastrointestinal tract (GI) and be a reservoir for reinfection of the genital tract. We hypothesize that there may be a differential susceptibility of organisms in the GI and genital tracts. To determine the effect of azithromycin on persistent chlamydial gut infection, C57BL/6 and BALB/c mice were infected orally and genitally and treated with azithromycin (Az) orally (20, 40, or 80 mg/kg of body weight), and the numbers of chlamydiae were determined from cervix and cecal tissues. The Az concentration in the cecum and cervix was measured by high-performance liquid chromatography with electrochemical detection (HPLC-ECD). Az treatment cleared genital infection in both C57BL/6 and BALB/c mice; however, GI infection was not cleared with the same doses. HPLC data showed the presence of Az at both sites of infection, and significant amounts of Az were measured in treatment groups. However, no significant difference in Az levels between the cecum and the cervix was observed, indicating similar levels of Az reaching both sites of infection. These data indicate that antibiotic levels that are sufficient to cure genital infection are ineffectual against GI infection. The results suggest a reevaluation of antibiotic therapy for chlamydial infection.

Chlamydial infection of the gastrointestinal tract: a reservoir for persistent infection

The mechanism by which chlamydiae persist in vivo remains undefined; however, chlamydiae in most animals persist in the gastrointestinal tract (GI) and are transmitted via the fecal-oral route. Oral infection of mice with Chlamydia muridarum was previously shown to establish a long-term persistent infection in the GI tract. In this study, BALB/c, DBA/2, and C57Bl/6 mice, infected orally with C. muridarum, were infected in the cecum for as long as 100 days in the absence of pathology. The primary target tissue was the cecum although the large intestine was also infected in most animals. A strong serum IgG and cecal IgA antibody response developed. Lymphocyte proliferation assays to chlamydial antigen on mesenteric lymph node cells were positive by day 10 and peaked on days 15-21, but the response returned to baseline levels by 50 days, despite the ongoing presence of the organism in the cecum. Because studies have shown that women and men become infected orally with chlamydiae, we propose that the GI tract is a site of persistent infection and that immune down-regulation in the gut allows chlamydiae to persist indefinitely. As a result, women may become reinfected via contamination of the genital tract from the lower GI tract.

Chlamydia trachomatis tonsillopharyngitis

Reports about the extragenital spread of Chlamydia trachomatis (CT) to oropharynx are limited. We report a male patient with progressive tonsillopharyngitis resistant to amoxicillin/clavulanic acid therapy. The patient presented 9 days after an orogenital and oroanal sexual intercourse with a female sex worker. The microimmunofluorescence revealed CT tonsillopharyngitis, and after completing a one-week course of doxycycline, the patient recovered completely. More cases of CT tonsillopharyngitis may be revealed if attention is paid to an association of sexual activity with enduring tonsillopharyngitis.

The value of testing multiple anatomic sites for gonorrhoea and chlamydia in sexually transmitted infection centres in the Netherlands, 2006–2010

National surveillance data from 2006 to 2010 of the Dutch sexually transmitted infection (STI) centres were used to analyse current practices on testing extragenital sites for chlamydia and gonorrhoea in men who have sex with men (MSM) and women. In MSM, 76.0% and 88.9% were tested at least at one extragenital site (pharyngeal and/or anorectal) for chlamydia and gonorrhoea, respectively; for women this was 20.5% and 30.2%. Testing more than one anatomic site differed by STI centre, ranging from 2% to 100%. In MSM tested at multiple sites, 63.0% and 66.5% of chlamydia and gonorrhoea diagnoses, respectively, would have been missed if screened at the urogenital site only, mainly anorectal infections. For women tested at multiple sites, the proportions of missed chlamydia and gonorrhoea diagnoses would have been 12.9% and 30.0%, respectively. Testing extragenital sites appears warranted, due to the numerous infections that would have been missed. Adding anorectal screening to urogenital screening for all MSM visiting an STI centre should be recommended. Since actual testing practices differ by centre, there is a need for clearer guidelines. Routine gonorrhoea and chlamydia screening at multiple sites in STI centres should be investigated further as this might be a more effective approach to reduce transmission than current practice.

Current concepts in bacterial sexually transmitted diseases

Sexually transmitted diseases (STDs) are the most common infectious diseases worldwide, with over 350 million new cases occurring each year, and have far-reaching health, social, and economic consequences. Failure to diagnose and treat STDs at an early stage may result in serious complications and sequelae. STDs are passed from person to person primarily by sexual contact and are classified into varied groups. Some cause mild, acute symptoms and some are life-threatening. They are caused by many different infectious organisms and are treated in different ways. Syphilis and gonorrhea are ancient afflictions. Now, however, Chlamydia is prevalent and has become the most common bacterial STD. Antimicrobial resistance of several sexually transmitted pathogens is increasing, rendering some regimens ineffective, adding to therapeutic problems. A standardized treatment protocol for STDs is recommended to ensure that all patients receive adequate treatment. Appropriate treatment of STDs is an important public health measure.

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

Sexually transmitted rectal infections with Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) have been well documented in men who have sex with men (MSM). Few studies have described infections in women who engage in anal intercourse. We performed testing for rectal infections in women who reported ano-receptive intercourse at the Miami Dade Health Department Sexually Transmitted Diseases (STD) clinic and report the prevalence and characteristics of women with rectal CT or GC infections. Our results revealed a prevalence of 17.5% for rectal chlamydia and 13.4% for rectal gonorrhoea. Urine-based screening alone would have missed 6% of rectal chlamydia infections and 35% of rectal gonorrhoea infections. Anal symptoms were reported in 12.5% of women with rectal chlamydia infections. The only associated factor identified was an age less than 28 years. We conclude that rectal screening for CT and GC should be included in STD prevention strategies, especially in the younger population.

Nucleic acid amplification tests for diagnosis of Neisseria gonorrhoeae and Chlamydia trachomatis rectal infections

It is uncertain which methods for the diagnosis of rectal gonococcal and chlamydial infection are optimal. This study evaluated the performance of culture and nucleic acid amplification tests (NAATs) for rectal chlamydial and gonococcal diagnosis. From July 2003 until February 2007, 441 rectal test sets were collected from individuals attending a sexually transmitted disease clinic and three HIV clinics who gave a history of anal intercourse or were women at high risk for Neisseria gonorrhoeae or Chlamydia trachomatis infections. Rectal swab specimens were tested using culture and commercial NAATs employing transcription-mediated amplification (TMA), strand displacement amplification (SDA), and PCR amplification. Test performance was evaluated using a rotating standard by which patients were classified as infected if either two or three comparator tests were positive. Test sensitivities for the detection of N. gonorrhoeae ranged from 66.7% to 71.9% for culture to 100% for TMA. Specificities were 99.7% to 100% for culture and greater than 95.5% for all three NAATs. Test sensitivities for C. trachomatis ranged from 36.1% to 45.7% for culture and among NAATS from 91.4% to 95.8% for PCR to 100% for TMA. Specificities of the NAATs ranged from 95.6% to 98.5% (two-of-three standard) and from 88.8% to 91.8% (three-of-three standard). Over 60% and 80% of gonococcal and chlamydial infections, respectively, among men who have sex with men and over 20% of chlamydial infections in women would have been missed if the rectal site had not been tested. Currently available NAATs are more sensitive for the detection of chlamydial and gonococcal infection at the rectal site than is culture.

Rectal Chlamydia trachomatis infection in women. Is it overlooked?

Screening for rectal chlamydia was not routinely offered in our department until we had a local outbreak of lymphogranuloma venereum (LGV) in men who have sex with men (MSM) in 2004/2005. We later decided to extend the screening to high-risk women (women who had receptive anal sex, contacts of gonorrhoea, women, with anorectal symptoms, women who had been sexually assaulted). A retrospective study of 152 women from whom 160 rectal chlamydia swabs were taken was carried out. Twenty (12.5%) swabs were positive, 19 of which were also positive at the cervix. All were non-LGV serovars. The groups at greatest risk were high-risk women aged less than 20 years and women with proven gonococcal infection where the prevalence was 22.6% and 30%, respectively. We conclude that rectal chlamydial infection in women may be common and further studies are needed to elucidate its importance.

Correlates and prevalence of HIV and sexually transmitted infections among Hijras (male transgenders) in Pakistan

This study explored the role of Hijras (male transgenders) as a core group in Pakistan's HIV epidemic. Four hundred and nine Hijras underwent detailed behavioural and biological assessment. Our subjects were young (median age: 24 years), debuted sex early and used alcohol and drugs. Sex with men, women and other Hijras along with co-habitation/marriage were reported. Most (84%) had sold sex. These reported a median of four times and at least one regular client weekly. Few used condoms. Most (94%) could identify a condom, but 42% reported never needing one. Over two-thirds had correct HIV and protective knowledge. Many reported experiencing physical abuse or forced sex (40%) and sexual orientation-related discrimination (45%). Most (58%) had sexually transmitted infections (STIs) and 38% had multiple infections. The commonest infections were syphilis (50%) and gonorrhoea (18%). Care-seeking was mainly (87%) from the private sector. High STI prevalence, commercial sex, bisexuality and infrequent protective behaviours are described. Their communal living and wider sexual networks suggest a more central role for Hijras in Pakistan's HIV epidemic. Effective HIV/STI control programmes must take the above factors into account to enrich their programme content.

Associations Between Condom Use and Rectal or Urethral Chlamydia Infection in Men

OBJECTIVE

To investigate the association of condom use with chlamydia infection in men attending a large sexually transmitted infection (STI) clinic in Australia.

STUDY

Computerized records for all attendances between July 2002 and June 2003 were included and separate analyses were performed for men reporting male-to-male sexual contact (MSM) and for men reporting heterosexual contact only (non-MSM). Associations among age, condom use, and number of partners with chlamydia infection were assessed.

RESULTS

Chlamydia was diagnosed at a rate of 8.6 cases per 100 consultations (95%CI: 7.1, 10.3) among MSM and at a rate of 6.8 cases per 100 consultations (95%CI: 5.9, 7.8) among non-MSM. Condom use was associated with a lower odds of rectal chlamydia but not urethral infection in MSM. Condom use was associated with lower odds of urethral chlamydia among non-MSM.

CONCLUSIONS

The findings suggest that condoms do provide some protection against rectal chlamydia infection in MSM and chlamydial urethritis in non-MSM, but other factors may play an important role in the transmission of chlamydial urethritis in MSM.

The Resurgence of Chlamydia trachomatis

The objective of the review is to alert reproductive-care providers to the unexpected resurgence of Chlamydia infections and to new findings related to complications associated with Chlamydia infection. Data sources consisted of national and local guidelines and literature searches of MEDLINE with the heading Chlamydia infections 2002 and 2003. The complications of Chlamydia infections are considered to be longterm, and may include debilitating pain, infertility, tubal pregnancy, cancer, and HIV infection. Only a strong disease-management response from reproductive-care providers, using new diagnostic techniques and simpler treatment regimens, as well as a strong public health reaction, will be effective to limit the scourges of Chlamydia infection in the female population.

The pig-tailed macaque rectal model: microflora and chlamydial infection

BACKGROUND

A topical microbicide should protect against acquisition of sexually transmitted infection during both vaginal and rectal intercourse. The rectal microflora of the Macaca nemestrina (pig-tailed macaque) and humans were examined, as well as the histopathology of rectal tissues. In a subset of macaques, a human rectal isolate of Chlamydia trachomatis was inoculated into the rectum to establish rectal chlamydial infection.

GOAL

To evaluate the comparability of the pig-tailed macaque rectal model with humans.

STUDY DESIGN

Rectal swabs were collected for microbiologic analysis to characterize normal microflora in pig-tailed macaques and humans. Subsequently, 10 macaques received a rectal inoculation with C trachomatis, serovar D, prepared from a clinical rectal isolate.

RESULTS

The rectal microflora of pig-tailed macaques (n = 80) were found to be comparable with the rectal flora of humans (n = 40). The prevalence of Lactobacillus in the rectum was higher in the macaques than in humans. Coliform and Enterococcus were decreased in the macaques, as compared with those of humans. In 9 of 10 macaques, rectal chlamydial infection was confirmed by culture or ligase chain reaction on days 2, 7, and 14 after inoculation. The test results were positive for rectal chlamydial infection by ligase chain reaction only for the remaining animal on day 14 after inoculation.

CONCLUSIONS

The findings demonstrate that the rectal environment of the pig-tailed macaque is a useful model for further evaluation of newly developed topical microbicides for rectal use. Furthermore, such products can be evaluated for protection against rectal chlamydial infection in this model.

Oral Chlamydia trachomatis in patients with established periodontitis

Periodontitis is considered a consequence of a pathogenic microbial infection at the periodontal site and host susceptibility factors. Periodontal research supports the association of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, and Bacteroides forsythus, and periodontitis; however, causality has not been demonstrated. In pursuit of the etiology of periodontitis, we hypothesized that the intracellular bacteria Chlamydia trachomatis may play a role. As a first step, a cross-sectional study of dental school clinic patients with established periodontitis were assessed for the presence of C. trachomatis in the oral cavity, and in particular from the lining epithelium of periodontal sites. C. trachomatis was detected using a direct fluorescent monoclonal antibody (DFA) in oral specimens from 7% (6/87) of the patients. Four patients tested positive in specimens from the lining epithelium of diseased periodontal sites, one patient tested positive in healthy periodontal sites, and one patient tested positive in the general mucosal specimen. In conclusion, this study provides preliminary evidence of C. trachomatis in the periodontal sites. Planned studies include the use of a more precise periodontal epithelial cell collection device, the newer nucleic acid amplification techniques to detect C. trachomatis, and additional populations to determine the association of C. trachomatis and periodontitis.

Oral sex and transmission of non-viral STIs

OBJECTIVES

To review the literature on the role of oral sex in the transmission of non-viral sexually transmitted infections (STIs).

METHOD

A Medline search was performed using the keywords oro-genital sex, and those specific to each infection. Further references were then taken from each article read.

CONCLUSIONS

Oral sex is a common sexual practice between both heterosexual and homosexual couples. Oro-genital sex is implicated as a route of transmission for gonorrhoea, syphilis, Chlamydia trachomatis, chancroid, and Neisseria meningitidis. Other respiratory organisms such as streptococci, Haemophilus influenzae, and Mycoplasma pneumoniae could also be transmitted by this route. Fellatio confers risk for acquisition of infection by the oral partner. Cunnilingus appears to predispose to recurrent vaginal candidiasis although the mechanism for this is unclear, while a link between oro-genital sex and bacterial vaginosis is currently being studied. Oro-anal sex is implicated in the transmission of various enteric infections. In view of the increased practice of oral sex this has become a more important potential route of transmission for oral, respiratory, and genital pathogens.

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

OBJECTIVE

To investigate, by use of the Amplicor PCR in a routine setting, the recovery rate of Chlamydia trachomatis in ano-rectal and pharyngeal swab samples obtained from males and females attending an STD clinic in relation to sexual practices, symptoms, and signs.

DESIGN

Data regarding sexual practices, and symptoms and signs related to the rectum and pharynx, were obtained from 196 females and 208 males, including 31 homosexuals and eight bisexuals. Swab samples were obtained from the urethra, rectum, and pharynx from all the patients. An additional endocervical swab sample was obtained from the females.

METHODS

All samples were analysed by the Amplicor PCR (Roche).

SETTING

Rudolph Bergh's Hospital, a clinic for sexually transmitted diseases situated in the centre of Copenhagen, Denmark.

RESULTS

The overall prevalence of urogenital C trachomatis infection was 9.2% (37/404). The specificity of the Amplicor PCR was 100% for both ano-rectal and pharyngeal swab samples. In females three (13%) of the 23 infections were detected only by testing an ano-rectal or throat swab sample. In homosexual males two (67%) of three infections were detected only by the anorectal swab sample. Ano-rectal intercourse without use of condom was reported by 44% of females and by 52% of homosexual males. Fellatio without condom use was reported by 91% of females, and 80% of heterosexual males practised cunnilingus. Pharyngeal infection, however, occurred only in females, and the presence of pharyngeal symptoms or signs seemed predictive for pharyngeal C trachomatis infection, for which the time of incubation or colonisation exceeded 3 months. The presence of ano-rectal signs or symptoms was not predictive for an ano-rectal C trachomatis infection.

CONCLUSION

The Amplicor PCR can be used on ano-rectal and pharyngeal swab samples. Ano-rectal swab samples should be obtained in females and homosexual males at high risk of being infected. Pharyngeal samples should be taken in females at high risk of being infected, especially when pharyngeal signs or symptoms are present.

Sexually transmitted diseases in men who have sex with men. Acquisition of gonorrhea and nongonococcal urethritis by fellatio and implications for STD/HIV prevention

BACKGROUND AND OBJECTIVES

Despite trends toward safer sex practices in homosexually active men, some such people remain at high risk for acquiring sexually transmitted diseases (STD). This study was designed to assess behavioral and demographic determinants of STD acquisition in men who have sex with men (MSM), to guide prevention interventions.

STUDY DESIGN

A cross-sectional medical record review was undertaken of MSM who attended an urban STD clinic from January, 1993 through December, 1994. Gonorrhea, chlamydial infection, Chlamydia-negative nongonococcal urethritis (NGU), and newly documented human immunodeficiency virus (HIV) infection were analyzed in relation to demographic and behavioral variables.

RESULTS

Among 1,253 MSM, 196 (15.6%) had nonchlamydial NGU, 105 (8.4%) had gonorrhea, 31 (2.5%) had chlamydial infection, and 162 (12.9%) had known or newly documented HIV infection. Known HIV infection was an independent predictor of urethral gonorrhea (odds ratio [OR] 2.3, 95% confidence interval [CI95] 1.2-4.8). Oral insertive intercourse was independently associated with urethral gonorrhea (OR 4.4, CI95 1.4-13.4) and nonchlamydial NGU (OR 2.2, CI95 1.3-3.7), and receptive anal intercourse was associated with newly documented HIV infection (OR 2.6, CI95 1.3-4.9). Neither number of sex partners nor condom use was associated with any incident STD outcome, including new HIV infection.

CONCLUSIONS

MSM who attend STD clinics represent a subgroup of homosexually active men who remain at high risk for STDs, including HIV infection. Fellatio, commonly thought to be a "safe" sexual practice, is an independent risk factor for urethral gonorrhea and nonchlamydial NGU. A history of consistent condom use or of few sex partners should not dissuade clinicians from performing screening tests for HIV and other STDs. Repeated STD screening and counseling about safer sex are indicated for many HIV-infected MSM.

Current methods of laboratory diagnosis of Chlamydia trachomatis infections

Infections caused by Chlamydia trachomatis are probably the most common sexually transmitted diseases in the United States. Commonly unrecognized and often inadequately treated, chlamydial infections can ascend the reproductive tract and cause pelvic inflammatory disease, which often results in the devastating consequences of infertility, ectopic pregnancy, or chronic pelvic pain. C. trachomatis infections are also known to increase the risk for human immunodeficiency virus infection. The obligate intracellular life cycle of C. trachomatis has traditionally required laboratory diagnostic tests that are technically demanding, labor-intensive, expensive, and difficult to access. In spite of these historical challenges, however, laboratory diagnosis of C. trachomatis has been a rapidly advancing area in which there is presently a wide array of commercial diagnostic technologies, costs, manufacturers. This review describes and compares the diagnostic methods for C. trachomatis infection that are currently approved for use in the United States, including the newest DNA amplification technologies which are yet to be licensed for commercial use. Issues to consider in selecting a test for purposes of screening versus diagnosis based on prevalence, performance, legal, social, and cost issues are also discussed.

Oral manifestations of selected sexually related conditions

The incidence of certain microbial infections occurring in the oropharynx is well documented, but infection by other pathogens, although highly probable, has not been established with certainty. Considerable recent interest in the incubation period of various infections and improved community surveillance programs combine to ascribe infection to specific incidents. It is prudent for health care personnel to acknowledge the presence of many sexually transmitted diseases in the oropharynx and consider them in the differential diagnosis of many well-established conditions.

Value of screening for oro-pharyngeal Chlamydia trachomatis infection

AIMS

To determine whether oro-pharyngeal colonisation by Chlamydia trachomatis occurs in patients at risk of genital chlamydia infection; to determine whether screening pharyngeal specimens by polymerase chain reaction (PCR) increases detection of C trachomatis compared with isolation and the immune dot blot test; and to correlate the detection of C trachomatis and Neisseria gonorrhoeae in the pharynx with a history of oro-genital contact.

METHODS

Thirteen homosexuals and 11 heterosexuals were included in the study. Urogenital and pharyngeal specimens were tested for C trachomatis and N gonorrhoeae using standard clinical diagnostic procedures. Two different PCR methodologies were also used to detect C trachomatis in the pharyngeal specimens. Results were correlated with the mode of sexual practice.

RESULTS

Oro-genital sexual contact was practised by 64.9% (72/111) of heterosexuals in addition to penetrative penovaginal intercourse. Additionally, 62.1% (77/124) of all patients did not use any form of barrier protection. Of those who admitted to oro-genital sexual contact, 17.6% of patients with a genital chlamydial infection and 36.4% of those with genital gonorrhoea also had asymptomatic pharyngeal colonisation. C trachomatis was detected in three of 124 (2.4%) pharyngeal specimens by PCR which were reported as negative by chlamydial culture; one was positive by the immune dot blot test.

CONCLUSION

The majority of patients practised unprotected oro-genital contact and significant pharyngeal colonisation by C trachomatis and N gonorrhoeae occurred if genital infection was present. Despite the use of PCR in a population at high risk of sexually transmitted disease, the prevalence of chlamydia in the pharynx was very low. This indicates that transmission of C trachomatis to the oro-pharynx does not pose a serious health risk and that screening of patients for oro-pharyngeal C trachomatis is not worthwhile.