Prevalence of Four Sexually Transmitted Infection Pathogens Detected in Urine and Genital Tract Secretion in Hangzhou, China.

BACKGROUND: Sexually transmitted infections (STIs) increase gradually and have become a public health problem in the world. UU, CT, NG, and MG are four common STI pathogens. Our retrospective study analyzed the clinical situation and the laboratory data of patients infected with the four pathogens. The prevalence of the four pathogens, detected in urine and genital tract secretion, was studied in Hangzhou, China. METHODS: A total of 3,168 male and female patients were randomly selected from February 2023 to February 2024. Urine and genital secretions were collected, and four STI pathogens were controlled for detection. Data were collected from the hospital's electronic medical records, and SPSS 25.0 software was used to perform a statistical analysis. RESULTS: Among 3,168 patients, a total of 1,527 were detected as positive, and the positive rate was 48.20%. The age of patients ranged from 13 - 98 years, with an average age of 45.6. The total of patients consisted of 2,191 males and 977 females, which had a significant difference (p < 0.05). Specimens were mainly collected from the Department of Dermatovenerology, Urological Surgery, Obstetrics and Gynecology, and so on. The positive rate was statistically different between male and female patients (p < 0.05). Single infection performed a main role and accounted for 79.57% of all of the positive patients. In the ≤ 20 age group, the positive rate was the highest and was as high as 77.65%. In detail, single infection caused by UU dominated, especially in the 21 - 30 age group. Double infection caused by UU and CT and triple infection caused by UU, CT, and NG were the majority, both especially in the 21 - 30 age group. There were significant differences in the positive rates in the different age groups and in the four pathogens (p < 0.05). Quadruple infection was very rare and had only been detected in one patient. CONCLUSIONS: The prevalence of the four pathogens in Hangzhou was different from other regions. More male than female patients, more single than multiple infections, and more single and multiple infections occurring in young people were the features in Hangzhou. The study would provide reference for prevention, diagnosis, and treatment of STI.

Association Between Sexually Transmitted Infections and the Urine Culture.

Introduction: Bacterial urinary tract infections (UTI) and some sexually transmitted infections (STI) can have overlapping signs and symptoms or nonspecific findings, such as pyuria on urinalysis. Furthermore, results from the urine culture and the nucleic acid amplification test for an STI may not be available during the clinical encounter. We sought to determine whether gonorrhea, chlamydia, and trichomoniasis are associated with bacteriuria, information that might aid in the differentiation of STIs and UTIs. Methods: We used multinomial logistic regression to analyze 9,650 encounters of female patients who were aged ≥18 years and who underwent testing for STIs. The ED encounters took place from April 18, 2014-March 7, 2017. We used a multivariable regression analysis to account for patient demographics, urinalysis findings, vaginal wet-mount results, and positive or negative (or no) findings from the urine culture and testing for Neisseria gonorrhoeae, Chlamydia trachomatis, or Trichomonas vaginalis. Results: In multivariable analysis, infection with T vaginalis, N gonorrhoeae, or C trachomatis was not associated with having a urine culture yielding 10,000 or more colony-forming units per mililiter (CFU/mL) of bacteria compared with a urine culture yielding less than 10,000 CFU/mL or no urine culture obtained. The diagnosis of a UTI in the ED was not associated with having a urine culture yielding 10,000 or more CFU/mL compared with a urine culture yielding less than 10,000 CFU/mL. Conclusion: After adjusting for covariates, no association was observed between urine culture results and testing positive for trichomoniasis, gonorrhea, or chlamydia. Our results suggest that having a concurrent STI and bacterial UTI is unlikely.

Knowledge about and prevalence of Chlamydia trachomatis in a population-based sample of emerging Croatian adults.

To determine the prevalence of genital Chlamydia trachomatis (chlamydia) infection, knowledge about chlamydia and experience of previous testing for chlamydia, we carried out a national probability-based survey in emerging adults aged 18-25 years in Croatia in 2021-2022. Participants (n = 1197), members of a national online panel, completed a web-based questionnaire that collected information on socio-demographics, sexual behaviours and knowledge about sexually transmitted infections (STIs). Urine specimens from a sample of sexually experienced participants were self-collected and tested for chlamydia using Cobas 4800 CT/NG test. To achieve broad representativeness of the emerging adult population in the country, we applied post-hoc weighting for gender and age. Multivariable ordinary least squares linear regression was used to determine correlates of knowledge about chlamydia infection and binomial logistic regression to assess correlates of the willingness to test for chlamydia. Among 448 participants who sent in their urine specimens chlamydia prevalence was 2.5% (95% CI 1.2-5.1) in women and 1.0% (0.3-3.2%) in men. A total of 8.0% of women and 4.7% men reported testing for chlamydia prior to the survey. About a quarter of the sample was characterized by not answering correctly any of the six questions related to knowledge about chlamydia, while only 9.6% had five or six correct answers. In the multivariable analysis, significantly higher odds of willingness to test for chlamydia were found in females compared to males (OR = 1.34, p = 0.024), those with better knowledge about the infection (OR = 1.11, p = 0.005), and those with lower religiosity (OR = 0.91, p = 0.017). In conclusion, prevalence of chlamydia in emerging adults in Croatia is considerable. Efforts to control this infection should focus on primary prevention and targeted testing combined with effective case management strategies.

Retrospective testing for mpox virus in routine STI screens from men who have sex with men in England, August-October 2022.

OBJECTIVES: A global outbreak of mpox (monkeypox) has been ongoing since 2022, with most cases in the UK detected in gay, bisexual and other men who have sex with men (GBMSM). Asymptomatic and pauci-symptomatic mpox infection has been reported outside of the UK. We aimed to investigate whether mpox could be detected in specimens from GBMSM in England who were attending sexual health services (SHSs) for asymptomatic sexually transmitted infection screening. METHODS: Anonymised, residual clinical specimens from GBMSM undertaking routine asymptomatic screening for gonorrhoea (Neisseria gonorrhoeae (NG)) and chlamydia (Chlamydia trachomatis (CT)) infection were tested for the presence of mpox virus. Specimens were collected between 1 August and 7 October 2022 from three SHSs in high-mpox incidence areas in England. Testing was performed using a dual-clade, mpox virus-specific real-time PCR. RESULTS: During the collection period, 2927 clinical specimens (951 pharyngeal swabs, 1022 urine specimens and 954 rectal swabs) were obtained from 1159 GBMSM. Mpox virus was detected in four specimens from two participants who attended the same SHS at different times (the first during the week 8-12 of August, the second during the week 19-23 of September). One participant was positive in the urine specimen only, while the other tested positive at all three sites. CONCLUSIONS: A very low prevalence (2 of 1159, 0.17%) of mpox infection was detected in GBMSM attending SHS in England for asymptomatic NG/CT screening, suggesting that undetected infection in this population was unlikely to be a main driver of transmission. Confirmed mpox cases in the UK declined from over 1100 per month in June and July to 764 cumulatively during the collection period. These data give reassurance that the observed reduction in cases during the collection period was not due to undetected infection or changes in presentation among SHS attendees. Currently, there is insufficient evidence to support routine testing of asymptomatic GBMSM for mpox infection in England.

Prevalence of leukocyturia in a cohort of French asymptomatic aircrews.

OBJECTIVES: Sexually transmitted infections (STIs) can cause leukocyturia. We aimed to estimate the prevalence of leukocyturia in asymptomatic aircrews and the proportion of STIs in those presenting leukocyturia. METHODS: The LEUCO survey was a prospective cohort study conducted among aircrews between 14th October 2019 and 13th March 2020 at the Toulon aeromedical centre in France. All participants performed a dipstick urinalysis. Those positive for leukocyturia were offered STI screening by nucleic acid amplification test (NAAT) for Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium and Trichomonas vaginalis. RESULTS: Among the 2236 included asymptomatic participants (1912 men and 324 women), 127 (36 men and 91 women) were positive for leukocyturia. The prevalence of leukocyturia was 1.9% (1.3-2.6) in men and 28.1% (23.3-33.3) in women (p < 0.001). In men positive for leukocyturia, the NAAT positivity rate for C. trachomatis, N. gonorrhoeae, M. genitalium and T. vaginalis was 28.6% (3.7-71.0) in the age group 18-24, 20.0% (0.5-71.6) in the age group 25-34, and zero in the older age group (p 0.65). In women positive for leukocyturia it was 16.7% (4.7-37.4) in the age group 18-24, 18.2% (2.3-51.8) in the age group 25-34, and zero in the older age group (p 0.16). CONCLUSIONS: In asymptomatic individuals, leukocyturia is rare in men and more common in women. In asymptomatic adults under 35 years of age with leukocyturia, multiplex NAAT shows a high proportion of STIs and might be useful in improving STI detection.

Vaginal leukocyte counts for predicting sexually transmitted infections in the emergency department.

BACKGROUND: The use of vaginal white blood cell (WBC) counts to predict sexually transmitted infections (STIs) in the emergency department (ED) is incompletely characterized. OBJECTIVES: Our objective was to assess the relationship between vaginal wet preparation WBC counts and STIs and to determine whether WBC counts of at least 11 WBCs per high-power field (HPF) could be useful for identifying STIs in women in the ED. METHODS: Female ED patients 18 years or older who were evaluated in a single health system between April 18, 2014, and March 7, 2017, and had a genital wet preparation WBC result were retrospectively examined using univariable and multivariable analysis. RESULTS: Vaginal wet preparation WBC counts were examined for 17,180 patient encounters. Vaginal WBC counts of at least 11 WBCs/HPF were associated with increased odds of having gonorrhea, chlamydia, or trichomoniasis. When this threshold was used for the diagnosis of each STI, sensitivity ranged from 48.2% to 53.9%, and specificity ranged from 67.2% to 68.8%. CONCLUSION: Women with STIs are more likely to have higher vaginal WBC counts. However, higher vaginal wet preparation WBC counts in isolation have limited diagnostic utility for gonorrhea, chlamydia, and trichomoniasis. Incorporation of age, urine leukocyte esterase results, and vaginal WBC counts provided a better predictor of an STI than vaginal WBC counts alone.

Is an Antenatal Screening for Chlamydia trachomatis Necessary in the Current Society?

A screening of Chlamydia trachomatis infection in young pregnant women (≤25 years old) and their newborns was conducted. A total of 136 women were tested with urine samples in the immediate postpartum period. The prevalence was 18.4% (95% confidence interval [CI]: 11.9-24.9%) (25/136) and the rate of perinatal transmission was 35% (7/20). These results support the need for antenatal screening programs in high-risk women in Madrid (Spain).

High-resolution multilocus sequence typing for Chlamydia trachomatis: improved results for clinical samples with low amounts of C. trachomatis DNA.

BACKGROUND: Several Multilocus Sequence Typing (MLST) schemes have been developed for Chlamydia trachomatis. Bom's MLST scheme for MLST is based on nested PCR amplification and sequencing of five hypervariable genes and ompA. In contrast to other Chlamydia MLST schemes, Bom's MLST scheme gives higher resolution and phylogenetic trees that are comparable to those from whole genome sequencing. However, poor results have been obtained with Bom's MLST scheme in clinical samples with low concentrations of Chlamydia DNA. RESULTS: In this work, we present an improved version of the scheme that is based on the same genes and MLST database as Bom's MLST scheme, but with newly designed primers for nested-1 and nested-2 steps under stringent conditions. Furthermore, we introduce a third primer set for the sequencing step, which considerably improves the performance of the assay. The improved primers were tested in-silico using a dataset of 141 Whole Genome Sequences (WGS) and in a comparative analysis of 32 clinical samples. Based on cycle threshold and melting curve analysis values obtained during Real-Time PCR of nested-1 & 2 steps, we developed a simple scoring scheme and flow chart that allow identification of reaction inhibitors as well as to predict with high accuracy amplification success. The improved MLST version was used to obtain a genovars distribution in patients attending an STI clinic in Tel Aviv. CONCLUSIONS: The newly developed MLST version showed great improvement of assay results for samples with very low concentrations of Chlamydia DNA. A similar concept could be applicable to other MLST schemes.

Performance of human papillomavirus DNA detection in residual specimens taken for Chlamydia trachomatis and Neisseria gonorrhoeae nucleic acid amplification testing in men who have sex with men.

OBJECTIVES: Rectal swab specimens, either alone or pooled with first-void urine (FVU) and pharyngeal swab specimens, are used to test for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infection in men who have sex with men (MSM). Following introduction of human papillomavirus (HPV) vaccination for MSM attending UK sexual health services (SHSs), HPV testing of residual CT/NG test specimens has been proposed to monitor HPV prevalence in this population. Performance of HPV detection in such specimens has not been evaluated previously. METHODS: MSM attending a UK SHS provided three specimens: (1) rectal swab for CT/NG, (2) pooled rectal/pharyngeal/FVU specimen for CT/NG and (3) dedicated anal swab for HPV. Specimen 3 and residual material from specimens 1 and 2 were tested for type-specific HPV DNA. HPV detection was by an in-house multiplex PCR and luminex-based genotyping assay. RESULTS: A total of 129 MSM were recruited with a mean age of 38.1 years; 24% were HIV-positive. Of the 129 MSM, 92 (71%) had any type-specific HPV DNA in ≥1 specimen; 80 (62%) had high risk (HR) HPV. Of 123 participants with sufficient residual pooled and dedicated specimens, 70 (56.9%) had detectable HPV on both, and 40 (32.5%) were negative on both; overall concordance was 89% (95% CI 83% to 94%), and kappa statistic was 0.78 (95% CI 0.66 to 0.89). Pooled samples had a 4.1% (95% CI -1.9% to 10.0%) higher test positivity rate than dedicated samples.Of 125 participants with sufficient residual rectal and specimens, 74 (59.2%) had detectable HPV on both, and 36 (28.8%) were negative on both; overall concordance was 88% (95% CI 81% to 93%), and kappa statistic was 0.74 (95% CI 0.61 to 0.86). Residual rectal samples had 5.6% (95%CI -0.6% to 11.8%) higher test positivity than dedicated samples. CONCLUSIONS: We observed high concordance between the dedicated and residual STI test specimens. Our data support the strategy of testing residual specimens for HPV prevalence monitoring in MSM to evaluate the impact of the targeted vaccination programme.

Rapid multiplex PCR assay for simultaneous detection of Neisseria gonorrhoeae and Chlamydia trachomatis in genitourinary samples: A 30-minute assay.

We developed a rapid multiplex PCR assay available in bedside for the simultaneous detection of Neisseria gonorrhoeae and Chlamydia trachomatis, which enables diagnosis in less than 30 minutes. In this study, we validated the clinical utility of this assay including its sensitivity and specificity for NG and CT detection.

Profile of sexually transmitted infections causing urethritis and a related inflammatory reaction in urine among heterosexual males: A flow-cytometry study.

BACKGROUND: Information about the use of flow cytometry in the diagnosis of male urethritis is scarce. The current study aims to evaluate the performance of flow cytometry on first-voided urine in males with infectious urethritis (Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium and Trichomonas vaginalis). METHODS: Male patients of the Andrology Centre (Tartu University Hospital, Estonia) were recruited during the period March 2015 -January 2018. Cases included 306 patients with infectious urethritis caused by Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium and/or Trichomonas vaginalis. The control group consisted of 192 patients without uro-genital complaints, negative tests for C. trachomatis, N. gonorrhoeae, M. genitalium and T. vaginalis from first-voided urine and no inflammation in first-voided urine, mid-stream urine and urine after prostate massage. C. trachomatis, N. gonorrhoeae, M. genitalium and T. vaginalis were detected from first-voided urine using polymerase chain reaction (PCR) method. First-voided urine was analysed using urine particle analyzer Sysmex UF-500i. RESULTS: The most prevalent infection was chlamydia (64.1%), followed by Mycoplasma genitalium (20.9%), gonorrhoea (7.8%) and trichomoniasis (1.6%). Gonorrhoea caused the highest flow-cytometric leucocyte/bacteria count, followed by chlamydia and Mycoplasma genitalium. Trichomonas vaginalis showed nearly absent inflammation in first-voided urine. Using an empiric flow-cytometry diagnostic threshold for urethritis in first-voided urine (leucocytes ≥ 15/µl and bacteria ≥ 20/µl) the total calculated sensitivity was over 90%. However, when applying such criteria for deciding whether to perform first-voided urine PCR for C. trachomatis, N. gonorrhoeae, M. genitalium and T. vaginalis or not, we could miss 23 cases with infectious urethritis that makes up 7,5% of all proven cases. CONCLUSIONS: Flow cytometry of first-voided urine can be considered as a rapid and objective screening method in case of suspected male infectious urethritis.

Recuperación de Chlamydia trachomatis y otros patógenos en la orina de varones con piuria estéril atendidos en urgencias / Recovery of Chlamydia trachomatis and other pathogens in urine from men with sterile pyuria attended in an emergency department

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Pooling of urine samples for molecular detection of Chlamydia trachomatis, Neisseria gonorrhoeae and Mycoplasma genitalium as a screening strategy among young adults in Catalonia / Pooling de muestras de orina para la detección molecular de Chlamydia trachomatis, Neisseria gonorrhoeae y Mycoplasma genitalium como estrategia de cribado entre la población joven en Cataluña

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

INTRODUCCIÓN: Las infecciones bacterianas de transmisión sexual (ITS) tienen un impacto importante en la salud reproductiva, destacando el aumento en las tasas de infección por Chlamydia trachomatis entre los jóvenes. Para reducir los costes de detección de las ITS, la estrategia de agrupación de muestras (pooling) es beneficiosa para pruebas de alto rendimiento en poblaciones de baja prevalencia utilizando muestras no invasivas. OBJETIVOS: 1) Describir el rendimiento de un ensayo de PCR 7-STI utilizando el pooling de 3 muestras de orina para detectar Chlamydia trachomatis, Neisseria gonorrhoeae y Mycoplasma genitalium; 2) Estimar el ahorro de la estrategia de pooling; 3) Describir la prevalencia, los factores de riesgo y las coinfecciones de Chlamydia trachomatis, Neisseria gonorrhoeae y Mycoplasma genitalium en jóvenes ≤ 25 años en Cataluña. MÉTODOS: Estudio transversal de prevalencia realizado durante 2016 entre jóvenes ≤ 25 años atendidos en centros de salud sexual y reproductiva en todo el territorio catalán a partir de pools de 3 muestras de orina. Se utilizó un cuestionario estandarizado para recopilar variables clínico-epidemiológicas y de comportamiento. RESULTADOS: Se testaron 1032 jóvenes. La prevalencia de Chlamydia trachomatis, Neisseria gonorrhoeae y Mycoplasma genitalium fue del 8,5, 0,6 y 3,5%, respectivamente. La estrategia de pooling proporcionó un ahorro del 33% en los costos de reactivo. CONCLUSIONES: La estrategia de pooling llevado a cabo para estudios epidemiológicos en nuestro contexto proporciona un ahorro que tiene un impacto en la viabilidad de los programas de detección de las ITS. De la misma manera, en este estudio se observa que la prevalencia de Chlamydia trachomatis continúa aumentando en esta población y, por primera vez en Cataluña, se determina la prevalencia de Mycoplasma genitalium en la población joven

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.

Prevalence of N. gonorrhoeae, C. trachomatis, M. genitalium, M. hominis and Ureaplasma spp. in the anus and urine among Japanese HIV-infected men who have sex with men.

The present study investigated the prevalence of Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma genitalium, M. hominis, and Ureaplasma spp. (biovars 1 and 2) in Japanese HIV-positive men who have sex with men (MSM). One-hundred-and-six Japanese HIV-infected MSM patients were enrolled. Anal and urine samples were collected and DNA testing for each microorganism was performed. Questionnaires regarding lifestyle habits and sexual behavior were administered. The prevalence of N. gonorrhoeae, C. trachomatis, M. genitalium, M. hominis, and Ureaplasma spp. in the anus was 5.6%, 8.9%, 4.4%, 5.6%, and 8.9%, respectively. A history of genital warts was an independent risk factor for detection of Mycoplasma spp. and Ureaplasma spp. The prevalence of these microorganisms in the anus of asymptomatic Japanese HIV-positive MSM was relatively high in agreement with previous reports from other countries.

Mycoplasma genitalium, Chlamydia trachomatis, and Neisseria gonorrhoeae Detected With Aptima Assays Performed on Self-Obtained Vaginal Swabs and Urine Collected at Home and in a Clinic.

Self-obtained vaginal swabs, first-void urine and pooled specimens were collected at home and in a clinic. Percent prevalence and collection site concordance was 30.3 and 100 for Mycoplasma genitalium (74.4% azithromycin resistant) 15.1 and 96.7 for Chlamydia trachomatis and 6.6 and 100 for Neisseria gonorrhoeae (27% ciprofloxacin-resistant).

Improving Tracking of Postdischarge Results of Sexually Transmitted Infection Screening Tests in Hospitalized Adolescents and Young Adults: A Quality Improvement Initiative.

Hospitalizations offer chlamydia and gonorrhea screening opportunities for youth who may not seek preventive care. Tracking of screening test results still pending after hospital discharge is an important component of clinical care. This process can be improved by protocol use and enhanced by effective, automated electronic health record tools.

Has Chlamydia trachomatis prevalence in young women in England, Scotland and Wales changed? Evidence from national probability surveys.

We evaluate the utility of the National Surveys of Attitudes and Sexual Lifestyles (Natsal) undertaken in 2000 and 2010, before and after the introduction of the National Chlamydia Screening Programme, as an evidence source for estimating the change in prevalence of Chlamydia trachomatis (CT) in England, Scotland and Wales. Both the 2000 and 2010 surveys tested urine samples for CT by Nucleic Acid Amplification Tests (NAATs). We examined the sources of uncertainty in estimates of CT prevalence change, including sample size and adjustments for test sensitivity and specificity, survey non-response and informative non-response. In 2000, the unadjusted CT prevalence was 4.22% in women aged 18-24 years; in 2010, CT prevalence was 3.92%, a non-significant absolute difference of 0.30 percentage points (95% credible interval -2.8 to 2.0). In addition to uncertainty due to small sample size, estimates were sensitive to specificity, survey non-response or informative non-response, such that plausible changes in any one of these would be enough to either reverse or double any likely change in prevalence. Alternative ways of monitoring changes in CT incidence and prevalence over time are discussed.