Validation of a New Duplex Real-Time Polymerase Chain Reaction for Chlamydia trachomatis DNA Detection in Ocular Swab Samples.

Trachoma is the world-leading infectious cause of preventable blindness and is caused by the bacteria Chlamydia trachomatis. In developing countries, diagnosis is usually based on clinical evaluation. Serological-based tests are cheaper than molecular-based ones, but the latter are more sensitive and specific. The present study developed a new duplex qPCR which concomitantly detects the C. trachomatis cryptic plasmid and the human 18S rRNA gene, with an LOD95% for C. trachomatis DNA of 13.04 genome equivalents per reaction. The new qPCR was tested using 50 samples from an endemic area and 12 from a non-endemic area that were previously characterized using direct immunofluorescence assay (DFA) and clinical evaluation. Among the 50 endemic samples, 3 were found to be positive by clinical evaluation (6%), 18 were found to be positive by DFA (36%), and 48 were found to be positive by qPCR (96%). Next, the new duplex qPCR was validated using 50 samples previously characterized by qPCR. Validation was carried out on a benchtop instrument (ABI7500) or on a portable point-of-care instrument (Q3-Plus), showing 95% specificity and 100% sensitivity. The ubiquitous presence of C. trachomatis DNA in samples from the endemic region confirms that constant monitoring is of paramount importance for the effective measurement of the elimination of trachoma. The newly developed duplex qPCR presented in this study, along with its validation in a portable qPCR system, constitutes important tools toward achieving this goal.

Heterogeneity in practitioner-reported barriers to use, cost considerations and priorities for point of care sexually transmitted infection tests on surveys across seven years.

BACKGROUND: Point of care diagnostic tests (POCTs) for sexually transmitted infections (STIs) have the potential to improve STI care worldwide. However, barriers to adoption, cost considerations and practitioner priorities may not be uniform globally and over time. We conducted two surveys, 7 years apart, among members of the International Union Against Sexually Transmitted Infections (IUSTI), and compare results here. METHODS: Surveys were given to members attending two IUSTI conferences in 2012 (Australia) and 2019 (Estonia). Descriptive analyses were performed and chi-square or Fisher's exact tests conducted. RESULTS: Amongst N = 190 participants in 2012 and N = 166 in 2019, 61% in 2012 and 77% in 2019 were from high-income countries (HICs). In 2012, 84% of respondents from low- and middle-income countries (LMICs) and 70% from HICs thought cost of test was more important than amount of reimbursement. Trends were similar in 2019. In 2012, unreliability was considered the most important barrier to POCT use by all groups, followed by being laboratory-driven and complexity. In 2019, time frame was considered most important, followed by unreliability and being laboratory-driven. In 2012, the top priority for POCT development among LMIC respondents was early HIV seroconversion (31%), versus chlamydia (57%) for HICs. In 2019, chlamydia remained top priority for HICs (40%), followed by early HIV seroconversion (19%) and gonorrhea (17%); top priorities for LMICs were chlamydia (26%), HPV (24%), and early HIV seroconversion (21%). CONCLUSIONS: Practitioner priorities for STI POCTs may be shifting. Cost may be critical to adoption in all settings. Larger studies are needed to verify findings.

Rapid tests for sexually transmitted diseases.

Many molecular diagnostic tests for sexually transmitted diseases (STDs) have been described recently but are not often accessible to clinicians in practice. There is a need for rapid, easy-to-perform, and accurate diagnostic tests for clinicians, especially for use in developing countries, where sophisticated laboratory support is often unavailable. Rapid tests, often termed "point-of-care" (POC) tests, can be performed in less than an hour in the doctor's office, clinic, or in a field setting. If simple laboratory equipment is available, a health care worker or clinician can make an immediate diagnosis of a STD. Progress has been made in the development of POC tests for HIV, syphilis, trichomonas, and bacterial vaginosis, but more work is needed for chlamydia and gonorrhea. Improvements in POCs will allow for faster treatment or provision of interventions in infected persons, in order to prevent transmission to partners or infants, thereby enabling effective control efforts for STDs.

Prevalence of Neisseria Gonorrhoeae among men screened for Chlamydia Trachomatis in four United States cities, 1999-2003.

OBJECTIVES: Neisseria gonorrhoeae infections are the second most commonly reported disease in the United States and cause significant morbidity. We describe the prevalence of gonorrhea in a large sample of men tested for gonorrhea and Chlamydia trachomatis in Baltimore, Denver, San Francisco, and Seattle. METHODS: Gonorrhea prevalence was measured among 17,712 men tested in a variety of non-sexually transmitted disease (STD) clinic venues using urine-based nucleic acid amplification tests. RESULTS: Among 16,850 asymptomatic men, prevalence ranged from 0% to 1.5% by city (P=0.20): Baltimore 1.3%, Denver 1.5%, San Francisco 1.5%, and Seattle 0%. Among 862 symptomatic men, the gonorrhea prevalence varied from 0.0% to 28.3% by city (P<0.01). CONCLUSIONS: The high prevalence of gonorrhea in symptomatic men supports the importance of testing for symptomatic men. The prevalence of gonorrhea among asymptomatic men is low, and routine screening cannot be recommended when screening is performed for chlamydia, unless a substantial local prevalence of gonorrhea can be documented in specific targeted venues or population groups.

Prevalence of Chlamydia trachomatis infection among men screened in 4 U.S. cities.

OBJECTIVE: The objective of this study was to measure the prevalence of Chlamydia trachomatis (CT) infection among men in clinical and nonclinical settings across the United States. GOAL: The goal of this study was to obtain data to inform recommendations regarding male CT screening. STUDY: The authors conducted a cross-sectional study of CT prevalence among adolescent and adult men in 4 U.S. cities (Baltimore, Denver, San Francisco, and Seattle). CT was detected using urine-based testing, and prevalence was calculated for first testing event. RESULTS: Over 23,000 men were tested for CT over a 3 1/2-year period. The majority (96%) were asymptomatic. Overall, prevalence was 7% and varied significantly between cities (range: Seattle, 1%; Baltimore, 12%), by age (peak prevalence at age 20-24 years, 9%), and between venues where CT testing was offered. CONCLUSIONS: At 7%, the prevalence of CT is moderately high among men opportunistically tested in nonclinical and clinical settings.