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

Rectal chlamydial infection among men who have sex with men: Partner notification as a means of nucleic acid amplification test validation

Nucleic acid amplification tests for the diagnosis of rectal chlamydial infection are not yet licenced. However, the detection of urethral Chlamydia trachomatis in sexual contacts of men who have sex with men (MSM) with rectal chlamydiae might support the validity of such tests. This was a retrospective study of the outcome of partner notification among MSM with rectal chlamydia who consecutively attended a sexually transmitted diseases clinic. During the study period, 5213 MSM attended the Department as new or ‘return new’ patients. There were 243 (5%) episodes of rectal chlamydial infection. In 87 men, at least one sexual partner was identified and attended the clinic. Overall, 34 (39%) of the 87 evaluable sexual contacts had urethral chlamydial infection. The finding of urethral C. trachomatis infection in a sizeable proportion of sexual contacts of men with rectal chlamydiae lends further support to the validation of the test system for the diagnosis of rectal chlamydia.

Bacterial sexually transmitted diseases

Common sexually transmitted bacterial organisms may affect the anorectum and perianal skin. While some of these infections are a result of contiguous spread from genital infection, most result from receptive anal intercourse. Polymicrobial infection is common and there is overlap in symptoms caused by the organisms that may infect the anorectum. This article addresses the most common bacterial organisms that are sexually transmitted and affect the anorectum. It includes discussions of gonorrhea, campylobacter, chlamydia, shigella, chancroid, granuloma inguinale, and syphilis. Incidence, mode of transmission, presenting signs and symptoms, diagnostic modalities, and treatment are reviewed.

Diagnóstico de la infección por Chlamydia trachomatis en un centro de diagnóstico y prevención de infecciones de transmisión sexual: evaluación de los exudados cervicales, uretrales y rectales mediante técnica de PCR

INTRODUCTION

The aim of this study is to analyze the clinical and epidemiological characteristics of Chlamydia trachomatis infection in patients attended in a clinic for sexually transmitted disease in Seville (Spain). Microbiological diagnosis was performed in various types of samples.

MATERIAL AND METHODS

The study included 3854 patients (50.8% women and 49.2% men, mean age 30.1 years) seen from 2002 to 2004. Among the total, 50% belonged to groups engaging in high risk sexual practices: female commercial sex workers (CSWs) (47%), men who maintain sexual relationships with other men (MSM) (45%), users of prostitution (4%), promiscuous heterosexual men (4%), those with a risk partner (2.7%) and injection drug users (IDU) (2.2%). We analyzed a total of 5978 samples (2384 cervical exudates, 2645 urethral exudates and 949 rectal exudates), for the detection of C. trachomatis by PCR technique with the COBAS Amplicor CT System.

RESULTS

Prevalence of C. trachomatis infection was 6% (4.3% in women and 7.8% in men). Among the total in women, 51.2% of positive samples were from women with high-risk sex factors and 73.8% of the women were asymptomatic. In men, the proportions were 70.5% and 36.9%, respectively. Cervical, urethral and rectal exudates yielded positive results in 4%, 4.9% and 4.3%, respectively.

CONCLUSIONS

Systematic sampling for C. trachomatis detection is necessary in symptomatic and asymptomatic patients practicing high-risk sex; periodic follow-up studies are also needed for early detection of sexually transmitted infection. Rectal sample collection is important for detecting this infection in MSM and in patients whose sexual habits make it advisable.

Sexually transmitted proctitis

Sexually transmitted infections such as chlamydia, gonorrhoea, herpes simplex virus and syphilis commonly present with rectal symptoms. Recent outbreaks of lymphogranuloma venereum among homosexual men throughout Europe highlight the need to consider sexually transmitted infections in the differential diagnosis of proctitis. This article examines the causative organisms, clinical features, diagnosis and treatment of sexually transmitted proctitis.

Prevalence of rectal, urethral, and pharyngeal chlamydia and gonorrhea detected in 2 clinical settings among men who have sex with men: San Francisco, California, 2003

BACKGROUND

The Centers for Disease Control and Prevention developed screening and diagnostic testing guidelines for chlamydia and gonorrhea at urethral, rectal, and pharyngeal sites for men who have sex with men (MSM). However, in most clinical settings, rectal chlamydial testing is not performed for MSM, and primarily sexually transmitted disease (STD) clinics alone perform routine rectal and pharyngeal gonorrhea screening for asymptomatic men.

METHODS

We evaluated the prevalence of rectal, urethral, and pharyngeal chlamydial and gonococcal infections among MSM seen at the municipal STD clinic and the gay men's community health center. We also determined the proportion of asymptomatic rectal infections, described the patterns of single and multiple anatomic sites of infection, and evaluated the proportion of chlamydial infections that would be missed and not treated if MSM were not routinely tested for chlamydia. We tested specimens using previously validated nucleic acid amplification tests (NAATs).

RESULTS

The prevalence of infection varied by anatomic site (chlamydia: rectal, 7.9%; urethral, 5.2%; and pharyngeal, 1.4%; for gonorrhea, rectal, 6.9%; urethral, 6.0%; and pharyngeal, 9.2%). Approximately 85% of rectal infections were asymptomatic supporting the need for routine screening. Because 53% of chlamydial infections and 64% of gonococcal infections were at nonurethral sites, these infections would be missed and not treated if only urethral screening was performed. In addition, >70% of chlamydial infections would be missed and not treated if MSM were tested only for gonorrhea.

CONCLUSIONS

Because these infections enhance both HIV transmission and susceptibility, clinical settings serving MSM should evaluate the prevalence of chlamydial and gonococcal infections by anatomic site using validated NAATs.

Sexually transmitted diseases in men

Sexually transmitted diseases are the most common infectious diseases in the United States. Physicians, nurses, and other health care providers are uncomfortable discussing sexual issues with their clients. Therefore many health care needs are not addressed, and many opportunities for education aimed at preventing STDs are missed. In the periodic health history, the health care provider must elicit information about sexual practices (vaginal,oral, or anal intercourse), sexual orientation (heterosexual, homosexual, or bisexual), sexual risk behaviors (ie, unprotected intercourse with multiple partners), contraceptive use (particularly condoms), and prior STDs. Based on this information, the health care practitioner moves to more specific questions regarding sexual health. The health care practitioner asks about sores on the penis, dripping or discharge from the penis, staining of the underwear, testicular pain, and scrotal swelling. For the client who engages in oral sex, the health care practitioner asks about sore throat. For the client who engages in anal intercourse ask about diarrhea, rectal bleeding, anal itching, and pain. Probe the desire phase, the arousal phase (erection), and the ejaculation phase. Ask about the desire for fatherhood and concerns about fatherhood. An important part of health care is prevention. Culturally specific and sensitive information should be available for patients. Patient education should not consist of simply handing a brochure to a man. Using the brochure as a guide for including all the necessary information and ascertaining the man's understanding may be a very effective method of patient education. For men who are at increased risk for STDs or who present with symptoms of STDs, offering diagnostic testing is necessary. Men who have multiple sexual partners especially need diagnostic testing and prevention counseling. The CDC recommends annual HIV and hepatitis C testing for men who have sex with men and other men who have increased risk for contracting HIV. Another important consideration at the periodic screening examination is the vaccinations that are to be recommended. Men who have sex with men should receive hepatitis A and hepatitis B vaccine. Additionally, it is recommended that all adolescents should receive hepatitis B vaccine.

Validation of roche COBAS Amplicor assay for detection of Chlamydia trachomatis in rectal and pharyngeal specimens by an omp1 PCR assay

Screening guidelines for men who have sex with men (MSM) recommend testing of extragenital sites (pharyngeal and rectal) for gonorrhoea and chlamydia. Testing of specimens from these sites is not validated by most commercial nucleic amplification tests, such as the COBAS Amplicor assay. To investigate the utility of the COBAS Amplicor assay for detection of Chlamydia trachomatis in extragenital specimens, this study developed and evaluated confirmatory tests using the omp1 gene as an alternative target for amplification by PCR. Of anal and throat swabs collected from men in male-only saunas, 52 swabs that tested C. trachomatis positive by COBAS Amplicor and 30 swabs that tested as negative were included for confirmatory omp1 PCR testing. A total of 49 (94%) COBAS Amplicor-positive samples were confirmed by the omp1 PCR. A substantial proportion of specimens were confirmed by using a nested omp1 PCR (27%). Not confirmed by any omp1 PCR were three anal swabs (6%). It is most probable that these samples contained lower bacterial levels that were near or below the detection level of the omp1 PCR assays. The findings of this study support the confident reporting of C. trachomatis detected by COBAS Amplicor in extragenital specimens and support the utility of this assay as a screening test for MSM.