The Performance of Pooled 3 Anatomic Site Testing for Chlamydia trachomatis and Neisseria gonorrhoeae Among Men Who Have Sex With Men and Transgender Women

Prevalence of Chlamydia trachomatis, Neisseria gonorrhoeae and Mycoplasma genitalium at pharyngeal and anorectal sites in patients presenting to an STI outpatient ward

BACKGROUND

The incidence of sexually transmitted infections (STIs) is unbridled and on the rise. Extragenital STIs (anal and pharyngeal infections) are commonly asymptomatic, resulting in delayed diagnosis and treatment and consequently higher chances of onward transmission.

OBJECTIVE

The aim of this observational single-centre study was to determine the prevalence of STIs at extragenital sites in symptomatic and asymptomatic patients presenting at an STI outpatient clinic.

METHODS

We conducted a retrospective analysis of patients who presented between October 2019 and February 2021 at the STI outpatient clinic of a tertiary centre in Central Europe. Patients were included in the study if they received at least one pharyngeal and/or anorectal swab in addition to a genital swab for multiplex-PCR STI diagnostics. Demographic data, symptoms and serological results were collected and analysed.

RESULTS

Data collected from 440 patients were analysed (mean age: 33.9 years, male: n = 345, 78.4%, female: n = 95, 21.6%). Ninety-seven males reported having sex with men (MSM); 174 patients identified as heterosexual (132 males, 42 females), and 10 females as bisexual. The sexual orientation was not reported in 159 cases. An STI was confirmed in 195 patients (44.3%) and, among those, 109 patients (55.9%) tested positive for an STI at extragenital sites. Seventy-one patients had a pharyngeal STI whereas 61 were infected in the anorectal region. Of those suffering from an extragenital STI, 64.2% (70 out of 109) tested negative for relevant pathogens at genital sites. The most frequently detected extragenital pathogen was Neisseria gonorrhoeae (71.8% of all pharyngeal STIs [51 out of 71], 55.7% of anorectal STIs [34 out of 61]), followed by Chlamydia trachomatis (41.0% of all anal infections [25 out of 61], 5.6% of pharyngeal infections [4 out of 71]). Pharyngeal and anorectal infections were asymptomatic in 88.7% [63 out of 71] and 65.6% [40 out of 61] of the cases, respectively.

CONCLUSION

These results underline the need to perform multisite testing, regardless of the presence of symptoms.

Using pooled urogenital, anorectal and oropharyngeal specimens to detect Chlamydia trachomatis and Neisseria gonorrhoeae among men who have sex with men in China: a multisite diagnostic accuracy study

OBJECTIVES

Screening for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) at both urogenital and extragenital sites has been recommended in many countries. Testing of the infections using pooled specimens from urogenital and extragenital sites offer the opportunity to shorten the testing time and reduce the testing cost. Ex-ante pooling is placing the original single-site specimens in a tube with transport media, while ex-post pooling is making a pool of the transport media from both anorectal and oropharyngeal specimens and the urine. This study aimed to conduct a multisite performance evaluation of two pool-specimen approaches (ex-ante and ex-post) in detection of CT and NG using the Cobas 4800 platform among men who have sex with men (MSM) in China.

DESIGN

Diagnostic accuracy study.

SETTING, PARTICIPANTS AND OUTCOME MEASURES

Participants were recruited from MSM communities at six cities in China. Two oropharyngeal and anorectal swabs collected by clinical staff and 20 mL first-void urine collected by the participant himself were used for evaluating sensitivity and specificity.

RESULTS

A total of 1311 specimens were collected from 437 participants in six cities. The sensitivities of ex-ante pooling approach as compared with single-specimen approach (reference standard) were 98.7% (95% CI, 92.7% to 100.0%) for detection of CT and 89.7% (95% CI, 75.8% to 97.1%) for NG, and the specificities were 99.5% (95% CI, 98.0% to 99.9%) and 98.7% (95% CI, 97.1% to 99.6%), respectively. The sensitivities of ex-post pooling approach were 98.7% (95% CI, 92.7% to 100.0%) for CT and 100.0% (95% CI, 91.0% to 100.0%) for NG, and the specificities were 100.0% (95% CI, 99.0% to 100.0%) and 100.0% (95% CI, 99.1% to 100.0%), respectively.

CONCLUSIONS

The ex-ante and ex-post pooling approaches show good sensitivity and specificity in detecting urogenital and extragenital CT and/or NG, indicating that these approaches can be used in epidemiological surveillance and clinical management of CT and NG infections, particularly among MSM population.

Pooling Rectal, Pharyngeal, and Urine Samples to Detect Neisseria gonorrhoeae, Chlamydia trachomatis, and Mycoplasma genitalium Using Multiplex Polymerase Chain Reaction Is as Effective as Single-Site Testing for Men Who Have Sex With Men

Background

Screening for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) at pharyngeal, urogenital, and anorectal sites is recommended for men who have sex with men (MSM). Pooling samples is a promising technique, but no data are available when pooled screening also includes Mycoplasma genitalium (MG). The main objective of this study was to examine the sensitivity of pooled samples for detecting CT, NG, and MG in MSM using nucleic acid amplification versus single-site testing.

Methods

In this multicenter study, MSM with a positive result for CT, NG, or MG were recalled to the clinic for treatment and were asked to participate in this study. Separate samples were sent to a central virological department that proceeded to form the pooled samples. Testing was performed using the multiplex real-time polymerase chain reaction Allplex STI Essential Assay (Seegene, Seoul, Korea), which can simultaneously detect 7 pathogens.

Results

A total of 130 MSM with at least 1 positive test for CT, NG, or MG were included. A total of 25.4% had a coinfection. The sensitivities of pooled-sample testing were 94.8% for CT, 97.0% for NG, and 92.3% for MG. Pooling failed to detect 8 infections, but pooled-sample analysis missed detecting only samples with a low bacterial load (cycle threshold >35).

Conclusions

Pooling samples from MSM to detect CT, NG, and MG is as sensitive as individual-site testing for these 3 pathogens using the Allplex assay. Missed infections with a very low bacterial load could have a low impact on further transmission.

Clinical Trials Registration. NCT03568695.

Pooled 3-Anatomic-Site Testing for Chlamydia trachomatis and Neisseria gonorrhoeae: A Systematic Review and Meta-Analysis

BACKGROUND

Pooled testing for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) may be a cost-saving solution to increase screening by simplifying testing procedures and reducing resource burdens. We conducted a systematic review and meta-analysis to examine the performance of pooled 3-anatomic-site testing (pharyngeal, rectal, and urogenital sites) for CT and NG in comparison with single-anatomic-site testing.

METHODS

We conducted a systematic literature search in PubMed, Embase, and Web of Science to identify original evaluation studies of the performance of pooled testing for CT and NG infections and identified 14 studies for inclusion. Each study was systematically evaluated for bias. We conducted bivariate fixed-effects and random-effects meta-analyses using a full Bayesian method of the positive percent agreement and negative percent agreement.

RESULTS

The combined positive percent agreement for CT was 93.11% (95% confidence interval [CI], 91.51%-94.55%), and the negative percent agreement was 99.44% (95% CI, 99.18%-99.65%). For NG, the combined positive percent agreement was 93.80% (95% CI, 90.26%-96.61%), and the negative percent agreement was 99.73% (95% CI, 99.30%-99.97%).

CONCLUSIONS

We found that pooled 3-anatomic-site tests performed similarly to single-anatomic-site tests for the detection of CT and NG. The pooled 3-anatomic-site tests have the added potential benefit of reduced cost and resource requirement, which could lead to improved testing access and screening uptake.