Screening for Chlamydia trachomatis and Neisseria gonorrhoeae Infections in Men Who Have Sex With Men: Diagnostic Accuracy of Nucleic Acid Amplification Test on Pooled Urine, Anorectal, and Pharyngeal Specimens

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.

Diagnosis and treatment of gonorrhoea: 2019 Belgian National guideline for primary care

OBJECTIVES

Gonorrhoea continues to be a public health concern in Belgium with pharyngeal and rectal infections increasing in persons with high-risk sexual behaviour. Belgian health care practitioners rely on international guidance when managing gonorrhoea resulting in non-adapted suboptimal care for the Belgian patient. This guideline will rectify this situation.

METHODS

This guideline was developed following an evidence-based approach and involving a guideline development group (GDG). Research questions were prioritised by the GDG and researchers conducted a systematic review of the evidence that was assessed using GRADE approach.

RESULTS

The guideline offers recommendations for gonorrhoea diagnosis, treatment and management for primary care professionals in Belgium and applies a risk group approach. This approach aims for improved identification of at-risk persons and targeted testing of at-risk groups; it includes behavioural questioning when deciding on diagnostic sampling and provides clear advice on treatment. The guideline defines when to add surveillance testing for antibiotic resistance, and what consists of good follow-up.

RESULTS

A concerted application of this guideline by all stakeholders in Belgium may result in improving the diagnosis of infections and eventually addressing the emerging multi-drug resistance.

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.

Swab-Yourself Trial With Economic Monitoring and Testing for Infections Collectively (SYSTEMATIC): Part 2. A Diagnostic Accuracy and Cost-effectiveness Study Comparing Rectal, Pharyngeal, and Urogenital Samples Analyzed Individually, Versus as a Pooled Specimen, for the Diagnosis of Gonorrhea and Chlamydia

BACKGROUND

Sexual history does not accurately identify those with extragenital Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT), so universal extragenital sampling is recommended. Nucleic acid amplification tests (NAATs) are expensive. If urogenital, plus rectal and pharyngeal, samples are analyzed, the diagnostic cost is trebled. Pooling samples into 1 NAAT container would cost the same as urogenital samples alone. We compared clinician triple samples analyzed individually with self-taken pooled samples for diagnostic accuracy, and cost, in men who have sex with men (MSM) and females.

METHODS

This was a prospective, convenience sample in United Kingdom sexual health clinic. Randomized order of clinician and self-samples from pharynx, rectum, plus first-catch urine (FCU) in MSM and vulvovaginal swabs (VVS) in females, for NG and CT detection.

RESULTS

Of 1793 participants (1284 females, 509 MSM), 116 had NG detected (75 urogenital, 83 rectum, 72 pharynx); 276 had CT detected (217 urogenital, 249 rectum, 63 pharynx). There was no difference in sensitivities between clinician triple samples and self-pooled specimens for NG (99.1% and 98.3%), but clinician samples analyzed individually identified 3% more chlamydia infections than pooled (99.3% and 96.0%; P = .027). However, pooled specimens identified more infections than VVS/FCU alone. Pooled specimens missed 2 NG and 11 CT infections, whereas VVS/FCU missed 41 NG and 58 CT infections. Self-taken pooled specimens were the most cost-effective.

CONCLUSIONS

FCU/VVS testing alone missed many infections. Self-taken pooled samples were as sensitive as clinician triple samples for identifying NG, but clinician samples analyzed individually identified 3% more CT infections than pooled. The extragenital sampling was achievable at no additional diagnostic cost to the FCU/VVS.

CLINICAL TRIALS REGISTRATION

NCT02371109.

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

BACKGROUND

Although molecular testing for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) is highly sensitive, the cost can be prohibitive. Those high costs are amplified when the recommended screening approach is used, which requires separate testing of specimens from 3 anatomic sites (rectal, pharyngeal and urogenital). Although individual molecular testing is standard of care, pooled testing may offer a cost-saving alternative.

METHODS

Using the Xpert® CT/NG assay (Cepheid, Sunnyvale, CA) we tested urine, rectal and pharyngeal swabs for CT and NG in a high-risk cohort of participants assigned male at birth who reported sex with other persons who were assigned male at birth. Remnant specimens (0.34 mL from each anatomic site) were combined to perform a single 'pooled' test. We calculated positive and negative percent agreement between the pooled testing results with standard of care Xpert CT/NG test results as the reference.

RESULTS

We conducted 644 pooled tests. Of those, 598 (92.3%) gave CT and NG results. The CT-positive and -negative percent agreement were 90.1% (95% confidence interval [CI], 80.7-95.9%) and 99.2% (98.1-99.8%), respectively. The NG-positive and -negative percent agreement were 96.2% (95% CI, 86.8-99.5%) and 99.8% (95% CI, 99.0-100%), respectively. Pooled testing identified 4 CT and 1 NG infections that were negative at all anatomic sites by individual testing.

CONCLUSIONS

Three-site pooled CT and NG testing performs similarly to single anatomic site testing among tests providing a valid result. Future cost analyses should evaluate the cost effectiveness of pooled 3-site testing to determine if such a strategy improves the feasibility and accessibility of molecular sexually transmitted infection testing.

To Pool or Not to Pool Samples for Sexually Transmitted Infections Detection in Men Who Have Sex With Men? An Evaluation of a New Pooling Method Using the GeneXpert Instrument in West Africa

BACKGROUND

Men who have sex with men (MSM) using preexposure prophylaxis (PrEP) are at risk for sexually transmitted infections (STIs). Therefore, PrEP services should include regular screening for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) at urethra, anorectum, and pharynx. However, financial and logistic challenges arise in low-resource settings. We assessed a new STI sample pooling method using the GeneXpert instrument among MSM initiating PrEP in West Africa.

METHODS

Urine, anorectal, and pharyngeal samples were pooled per individual for analysis. In case of an invalid result only (strategy 1) or a positive result of the pool (strategy 2), samples were analyzed individually to identify the infection's biological location. The results of 2 different pooling strategies were compared against the individual results obtained by a criterion standard.

RESULTS

We found a prevalence of 14.5% for chlamydia and 11.5% for gonorrhea, with a predominance of infections being extragenital (77.6%). The majority of infections were asymptomatic (88.2%). The pooling strategy 1, had a sensitivity, specificity and agreement for CT of 95.4%, 98.7%, and 0.93, respectively; and 92.3%, 99.2%, and 0.93 for pooling strategy 2. For NG, these figures were 88.9%, 97.7%, and 0.85 for strategy 1, and 88.9%, 96.7%, and 0.81 for strategy 2.

CONCLUSIONS

West African MSM have a high prevalence of extragenital and asymptomatic STIs. The GeneXpert method provides an opportunity to move from syndromic toward etiological STI diagnosis in low-income countries, as the platform is available in African countries for tuberculosis testing. Pooling will reduce costs of triple site testing.

Optimizing Strategies for Chlamydia trachomatis and Neisseria gonorrhoeae Screening in Men Who Have Sex With Men: A Modeling Study

BACKGROUND

International guidelines recommend the systematic screening for Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) infections in all men who have sex with men (MSM) who have engaged in unprotected sex. However, the optimal screening strategy remains unclear. We developed a modeling approach to optimize NG/CT screening strategy in MSM.

METHODS

A compartmental model of NG/CT screening and infection was implemented. NG/CT anal, pharyngeal, and urine (APU) samples from MSM attending the sexually transmitted infections clinic were used to estimate the screening rate, prevalence, and incidence in a base case scenario. Different screening strategies (scenarios; S) were then evaluated: APU samples every 12 months (S1); APU samples every 3 months (S2); APU samples every 6 months (S3); anal and pharyngeal (AP) samples every 6 months (S4); and AP samples every 3 months (S5).

RESULTS

We analyzed 2973 triplet APU samples from 1255 patients. We observed 485 NG and 379 CT diagnoses. NG/CT prevalence and incidence estimates were 12.0/11.1% and 40/29 per 100 person-years, respectively, in the base case scenario. As compared to S2, the reference strategy, the proportions of missed NG/CT diagnoses were 42.0/41.2% with S1, 21.8/22.5% with S3, 25.6/28.3% with S4, and 6.3/10.5% with S5, respectively. As compared to S2, S1 reduced the cost of the analysis by 74%, S3 by 50%, S4 by 66%, and S5 by 33%. The numbers needed to screen for catching up the missed NG/CT diagnoses were 49/67 with S1, 62/82 with S3, 71/87 with S4, and 143/118 with S5.

CONCLUSIONS

S5 appears to be the best strategy, missing only 6.3/10.5% of NG/CT diagnoses, for a cost reduction of 33%.

Modified self-obtained pooled sampling to screen for Chlamydia trachomatis and Neisseria gonorrhoeae infections in men who have sex with men

OBJECTIVES

To assess whether pooled sample testing with nucleic acid amplification tests was a potential alternative to three single-site sample testing to screen for Chlamydia trachomatis and Neisseria gonorrhoeae infections in asymptomatic men who have sex with men.

METHODS

We prospectively compared pooled sample testing with single-site sample testing in asymptomatic MSM. Self-obtained paired rectal samples, one gargle sample and one first-void urine sample were collected from participants to generate two sets of samples: one for pooled sample testing and the other for single-site testing. We used modified pooled sampling, which is defined as the use of gargle samples, instead of swabs, for the pooled sample to test for pharyngeal infection.

RESULTS

This study included 513 MSM. The positive rates of C. trachomatis and N. gonorrhoeae were 20.3% and 11.7%, respectively, for single-site sample testing. Compared with the sensitivity of single-site testing as the gold standard, the sensitivities of pooled sample testing for C. trachomatis and N. gonorrhoeae were 94.2% (95% CI 88.0% to 97.3%) and 98.3% (95% CI 90.9% to 99.9%), respectively. The concordance rate and kappa coefficient were 98.3% (95% CI 96.7% to 99.2%) and 0.945 (95% CI 0.859 to 1.000), respectively, for C. trachomatis and 98.8% (95% CI 90.1% to 100%) and 0.943 (95% CI 0.857 to 1.000), respectively, for N. gonorrhoeae.

CONCLUSIONS

The modified pooled sampling had a comparably high consistency with single-site sample testing. The results strongly suggest that the gargle sample is suitable as a part of pooled sample for STI screening of C. trachomatis and N. gonorrhoeae.

Fingerprint Biometric System Hygiene and the Risk of COVID-19 Transmission

Biometric systems use scanners to verify the identity of human beings by measuring the patterns of their behavioral or physiological characteristics. Some biometric systems are contactless and do not require direct touch to perform these measurements; others, such as fingerprint verification systems, require the user to make direct physical contact with the scanner for a specified duration for the biometric pattern of the user to be properly read and measured. This may increase the possibility of contamination with harmful microbial pathogens or of cross-contamination of food and water by subsequent users. Physical contact also increases the likelihood of inoculation of harmful microbial pathogens into the respiratory tract, thereby triggering infectious diseases. In this viewpoint, we establish the likelihood of infectious disease transmission through touch-based fingerprint biometric devices and discuss control measures to curb the spread of infectious diseases, including COVID-19.

To pool or not to pool? Screening of Chlamydia trachomatis and Neisseria gonorrhoeae in female sex workers: pooled versus single-site testing

OBJECTIVES

As Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are the most commonly reported STIs in Belgium and the majority of women infected are asymptomatic, targeted screening of patients in specified risk groups is indicated. To prevent long-term complications and interrupt transmission, extragenital samples should be included. As this comes with a substantial extra cost, analysis of a pooled sample from vaginal and extragenital sites could be a solution. In this study, we evaluated the feasibility of molecular testing for CT and NG in pooled versus single-site samples in a large cohort of female sex workers.

METHODS

Women were sampled from three anatomical sites: a pharyngeal, a vaginal and a rectal swab. Each sample was vortexed, and 400 µL of transport medium from each sample site was pooled into an empty tube. NAAT was performed using the Abbott RealTime CT/NG assay on the m2000sp/rt system.

RESULTS

We included 489 patients: 5.1% were positive for CT; 2.0% were positive for NG and 1.4% were coinfected, resulting in an overall prevalence of 6.5% (95% CI 4.5% to 9.1%) for CT and 3.5% (95% CI 2.0% to 5.5%) for NG. From the 42 patients positive on at least one non-pooled sample, only 5 gave a negative result on the pooled sample, resulting in a sensitivity of 94% (95% CI 79% to 99%) for CT and 82% (95% CI 57% to 96%) for NG. The missed pooled samples were all derived from single-site infections with low bacterial loads. The possibility of inadequate self-sampling as a cause of false negativity was excluded, as 4/5 were collected by the physician. Testing only vaginal samples would have led to missing 40% of CT infections and 60% of NG infections.

CONCLUSIONS

Pooling of samples is a cost-saving strategy for the detection of CT and NG in women, with minimal decrease in sensitivity. By reducing costs, more patients and more extragenital samples can be tested, resulting in higher detection rates.

Pooling Pharyngeal, Anorectal, and Urogenital Samples for Screening Asymptomatic Men Who Have Sex with Men for Chlamydia trachomatis and Neisseria gonorrhoeae

Screening for Chlamydia trachomatis and Neisseria gonorrhoeae at the pharyngeal, urogenital, and anorectal sites is recommended for men who have sex with men (MSM). Combining the three individual-site samples into a single pooled sample could result in significant cost savings, provided there is no significant sensitivity reduction. The aim of this study was to examine the sensitivity of pooled samples for detecting chlamydia and gonorrhea in asymptomatic MSM using a nucleic acid amplification test. Asymptomatic MSM who tested positive for chlamydia or gonorrhoea were invited to participate. Paired samples were obtained from participants prior to administration of treatment. To form the pooled sample, the anorectal swab was agitated in the urine specimen transport tube and then discarded. The pharyngeal swab and 2 ml of urine sample were then added to the tube. The difference in sensitivity between testing of pooled samples and individual-site testing was calculated against an expanded gold standard, where an individual is considered positive if either pooled-sample or individual-site testing returns a positive result. All samples were tested using the Aptima Combo 2 assay. A total of 162 MSM were enrolled in the study. Sensitivities of pooled-sample testing were 86% (94/109; 95% confidence interval [CI], 79 to 92%]) for chlamydia and 91% (73/80; 95% CI, 83 to 96%) for gonorrhea. The sensitivity reduction was significant for chlamydia (P = 0.02) but not for gonorrhea (P = 0.34). Pooling caused 22 infections (15 chlamydia and 7 gonorrhoea) to be missed, and the majority were single-site infections (19/22). Pooling urogenital and extragenital samples from asymptomatic MSM reduced the sensitivity of detection by approximately 10% for chlamydia but not for gonorrhea.

Take three, test one: a cross-sectional study to evaluate the molecular detection of Chlamydia trachomatis and Neisseria gonorrhoeae in pooled pharyngeal, anorectal and urine samples versus single-site testing among men who have sex with men in Belgium

Objectives: To investigate the efficacy of performing a pooling strategy of triple-anatomical site samples (pharyngeal, anorectal and urine samples) for simultaneous Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) nucleic acid amplification detection.Methods: A total of 117 specimen sets (pharyngeal, anorectal and urine) were collected from 98 men between 2014 and 2016. Double sampling of pharyngeal, anorectal and urine samples allowed for pooled and unpooled analyses using a multiplex Abbott Real Time CT/NG assay, together with confirmatory PCR testing in case of CT/NG positivity. Clinical and demographic data were analyzed.Results: The positivity rate for the triple-site pooled testing for CT and NG was 8.5% (10/117) and 6.8%, (8/117), respectively, compared to the single-site testing total positivity rate, which was 9.4% (11/117) and 4.3% (5/117) for CT and NG, respectively. Pooled analysis missed one CT-positive urine sample and one CT-positive anorectal sample could not be confirmed. In addition, less PCR inhibition was reported for the pooled sample (PS) testing and ERV-3 qPCR testing revealed ineffective sampling of self-collected anorectal swabs in two cases. No pharyngeal samples were positive for CT, nor were any urine samples positive for NG.Conclusion: This small study showed that PS testing is a possible testing strategy for screening high-risk men who have sex with men attending pre-exposure prophylaxis (PrEP) clinics. However, due to the low positivity rate of CT/NG in this study, larger evaluations are needed to confirm the effectiveness of CT/NG screening with multiple-site PS nucleic acid amplification test (NAAT) screening practices.

Reduced sensitivity from pooled urine, pharyngeal and rectal specimens when using a molecular assay for the detection of chlamydia and gonorrhoea near the point of care

Background The aim of this study was to compare the performance of pooled self-collected urogenital, pharyngeal and anorectal specimens to that of individual specimen results for the molecular detection of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) near the point of care (POC) for diagnostic sensitivity.

METHODS

Clients (mostly men who have sex with men) attending an urban community testing service and three sex-on-premises venues in Brisbane, Australia, were offered CT and NG testing by trained lay providers. Participants provided three self-collected specimens (urine, pharyngeal and rectal) for testing by GeneXpert (Cepheid, Sunnyvale, CA, USA). If any of the individual specimens from a participant were positive, all three specimens were pooled and retested.

RESULTS

Of the 388 participants who provided three individual anatomical specimens, 76 (19.6%) were found to be positive for CT and/or NG at one or more sites. The pooling approach failed to detect five CT rectal and four NG pharyngeal infections. The overall performance (sensitivity) of the pooling approach compared with individual specimen testing and Cohen's κ were 90.0% and 0.86 respectively for CT and 89.7% and 0.89 respectively for NG.

CONCLUSIONS

Reduced sensitivity was observed when using pooled specimens for the detection of CT and NG using GeneXpert near the POC, similar to results reported in laboratory-based CT and NG pooling studies. These data suggest specimen pooling is feasible near to the POC, potentially saving time and costs when screening at-risk populations for CT and NG. Our data also suggest a reduction in pooled urine could improve overall test sensitivity.

Pooling of urine samples for molecular detection of Chlamydia trachomatis, Neisseria gonorrhoeae and Mycoplasma genitalium as a screening strategy among young adults in Catalonia

INTRODUCTION

Bacterial sexually transmitted infections (STIs) have an important impact on reproductive health, highlighting the increase in Chlamydia trachomatis infection rates among young people. To reduce the costs of STI detection, the pooling strategy is beneficial for high-throughput tests in low-prevalence populations using non-invasive samples.

OBJECTIVES

(1) To describe the performance of a 7-STI PCR assay using the pooling of three urine samples to detect C. trachomatis, Neisseria gonorrhoeae and Mycoplasma genitalium; (2) to estimate the cost saving of the pooling strategy; (3) to describe the prevalence, risk factors and coinfections of C. trachomatis, N. gonorrhoeae and M. genitalium in young people ≤25 years in Catalonia.

METHODS

cross-sectional prevalence study conducted in 2016 among young people ≤25 years of age seen in sexual and reproductive health centres throughout Catalonia from pools of three urine samples. A standardized questionnaire was used to collect clinical-epidemiological and behavioural variables.

RESULTS

1032 young people were tested. The prevalence of C. trachomatis, N. gonorrhoeae and M. genitalium was 8.5%, 0.6% and 3.5%, respectively. The pooling strategy provided a 33% savings in reagent costs.

CONCLUSIONS

The pooling strategy implemented for epidemiological studies in our context provides a savings that has an impact on the viability of STI detection programmes. In the same way, this study shows that C. trachomatis prevalence continues to increase in this population and, for the first time in Catalonia, the prevalence of M. genitalium in young people is shown.