Detection Of Chlamydia Trachomatis Research Articles

Viability of Chlamydia trachomatis in different anatomical sites - a systematic review & meta-analysis.

Modern assays for the detection of Chlamydia trachomatis (CT) rely on nucleic acid amplification testing (NAAT) of DNA or ribosomal RNA. However, it is also known that both viable ("living") & non-viable ("dead") CT can be detected by NAAT. Multiple laboratory techniques to measure CT viability have emerged. We searched PubMed, EMBASE, Scopus and Dimensions as well as conference abstracts for entries between January 2000 to May 2023. We included any studies that measured CT viability among NAAT-positive samples. Viability assays include enhanced cell culture, direct fluorescent antibody (DFA), messenger RNA (mRNA) detection via digital droplet PCR (ddPCR), viability PCR (V-PCR) & real-time PCR measuring RNA-to-DNA ratio (RDR) (e.g. InSignia®). A meta-analysis was performed on the proportions of non-viable CT by anatomical site. We screened 31,342 records and included 16 studies in the analysis. The pooled proportions of non-viable CT by site were: 33% (95%CI 19-47%) in rectal swabs (eight studies), 17% (95%CI 7-27%) in cervical swabs (six studies), 15% (95%CI 6-25%) in vaginal swabs (six studies) and 11% (95%CI 9-17%) in urine/urethral swabs (two studies). All included studies found that a proportion of NAAT-detected CT is non-viable. The findings have far-reaching implications for screening programs and studies evaluating new STI tests and antimicrobial regimens.

Addressing Challenges in Chlamydia trachomatis Detection: A Comparative Review of Diagnostic Methods

Chlamydial infections are one of the most common sexually transmitted bacterial infections worldwide, which is related to serious consequences for the mental, sexual, and reproductive health of women and men. The infection is commonly asymptomatic; consequently, screening programs for infection control have been introduced in some countries. The detection methods of Chlamydia trachomatis infections have evolved since the establishment of the first gold-standard detection method in the 1970s, the culture assay. Over the decades, many efforts were made to find methods with a higher sensitivity, until the 1990s, when, as a result of advances in molecular biology, nucleic acid amplification tests came into use with more sensitivity, and, currently, there are several available with which to detect infection. Therefore, herein, we will review the main methods used for CT detection and the differences between them, in terms of targets, infections that can be detected, sensitivity, and specificity. We will focus on some of the FDA-approved CT detection tests and highlight the major advantages and superiority of using molecular biology techniques. In addition, we will examine the larger challenges and limitations of the methods currently in use and discuss how they might be surpassed. Moreover, in this review, we will describe the next step to carry out after testing positive for CT infection.

Clinical profile and molecular detection of Chlamydia trachomatis in follicular conjunctivitis: Insights from Egypt

Clinical profile and molecular detection of Chlamydia trachomatis in follicular conjunctivitis: Insights from Egypt

Performance of Cepheid CT/NG Xpert rapid PCR test for detection of Chlamydia trachomatis and Neisseria gonorrhoeae at a tertiary care centre in North India

IntroductionChlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are prevalent causes of sexually transmitted infections (STIs) globally, leading to substantial morbidity and transmission risks. MethodsThis study evaluates the diagnostic efficacy of Xpert CT/NG compared to conventional PCR and culture methods in 121 patients at a tertiary care centre in North India. ResultsXpert CT/NG demonstrated high sensitivity (85.8%) and specificity (96.3%) outperforming conventional PCR. Xpert CT/NG's rapidity and accuracy underscore its utility in timely diagnosis and control of STIs. ConclusionAs sexually transmitted infections pose a serious health concern implementation of such rapid diagnostic methods/point of care testing methods are to be implemented for early diagnosis.

Multi-repeat sequences identification using genome mining techniques for developing highly sensitive molecular diagnostic assay for the detection of Chlamydia trachomatis.

Chlamydia trachomatis ( C. trachomatis) is a common sexually transmitted infection (STI). In 2019, the World Health Organization reported about 131 million infections. The majority of infected patients are asymptomatic with cases remaining undetected. It is likely that missed C. trachomatis infections contribute to preventable adverse health outcomes in women and children. Consequently, there is an urgent need of developing efficient diagnostic methods. In this study, genome-mining approaches to identify identical multi-repeat sequences (IMRS) distributed throughout the C. trachomatis genome were used to design a primer pair that would target regions in the genome. Genomic DNA was 10-fold serially diluted (100pg/μL to 1×10 -3pg/μL) and used as DNA template for PCR reactions. The gold standard PCR using 16S rRNA primers was also run as a comparative test, and products were resolved on agarose gel. The novel assay, C. trachomatis IMRS-PCR, had an analytical sensitivity of 4.31 pg/µL, representing better sensitivity compared with 16S rRNA PCR (9.5 fg/µL). Our experimental data demonstrate the successful development of lateral flow and isothermal assays for detecting C. trachomatis DNA with potential use in field settings. There is a potential to implement this concept in miniaturized, isothermal, microfluidic platforms, and laboratory-on-a-chip diagnostic devices for reliable point-of-care testing.

Genital Infections in Couple Infertility in Dakar

Background: Couple infertility is a real public health problem affecting 8–15% of couples worldwide. The aim of this study was to investigate genital infections in infertile couples in Dakar. Methodology: This was an 8-month prospective study of infertile couples followed up in 3 health facilities in the Dakar region. Standard bacteriology was performed on genital swabs and Triplex PCR for the detection of Neisseria gonorrhoea, Chlamydia trachomatis and Mycoplasma genitalium. Data analysis was performed using SPSS IBM 25 software. Results: A total of 98 women (65.3%) and 52 men (34.7%) with an average age of 34 years and extremes ranging from 18 to 56 years were included. In men, the prevalence of genital infections was 17.3% (n=9), with a predominance of Mycoplasma hominis (5.8%), Ureaplasma urealyticum (5.8%) and Escherichia coli (3. 8%). In women, 70.3% (n=59) had an infection, and the most frequently isolated germs were G. vaginalis (19%), U. urealyticum (17%) and Candida albicans (17%). Neisseria gonorrhoeae and Mycoplasma genitalium were absent in all patients. Chlamydia trachomatis, on the other hand, was positive in 10 patients using antigenic tests, with confirmation in just one patient by PCR. Conclusion: The prevalence of genital infections in infertile couples was very high in our study. Good medical management of these infections necessarily requires good laboratory diagnosis.

Low-cost conventional PCR techniques enable simultaneous detection of bacterial sexually transmitted infections with enhanced sensitivity and specificity

PurposeNeisseria gonorrhoeae (NG), Chlamydia trachomatis (CT) and Mycoplasma hominis (MH), the three most common treatable bacterial sexually transmitted infections (STIs) worldwide can lead to many complications if remain untreated. Screening of high-risk population with highly sensitive methods will lead to significant improvement in patient outcomes and will prevent downward transmission. The advantages of Polymerase chain reaction (PCR) based assay are not only high sensitivity and specificity, but also detection of multiple organisms in a single reaction which reduce the result turn-around time. The aim of the present study was to evaluate the feasibility of a multiplex PCR assay method targeting 16S rRNA gene for simultaneous detection of NG, CT and MH infection along with their trend and occurrence among high-risk population in Assam, Northeast India. MethodsA cross-sectional study was undertaken, where a total of 200 randomly selected patients from high-risk population were included. After validation of singleplex PCR, Multiplex PCR (M-PCR) was performed along with the traditional culture method for NG. Results & conclusionThe overall agreement of M-PCR with singleplex PCR was very high (100%). The occurrence of STI was found to be very high (101/200; 50.5%). Furthermore, co-infection was detected in 10/200; 5%) individuals. Infection was more common among young individuals (p < 0.05) and males out-numbered females (p < 0.05). The most common organism detected was CT (42/200; 21%) followed by NG (41/200; 20.5%) and MH (20/200; 10%). The M-PCR assay workflow is simple, cost effective and can be used in routine diagnostic laboratories with basic molecular facilities.

Aerobic vaginitis is associated with carbonic anhydrase IX in cervical intraepithelial neoplasia

The aim of this study was to analyze the association between vaginal microbiota, carbonic anhydrase IX (CAIX) and histological findings of cervical intraepithelial neoplasia (CIN). The study included 132 females, among them 66 were diagnosed with high-grade intraepithelial lesion (CIN2, CIN3, and cancer), 14 with low-grade disease, and 52 assigned to the control group. An interview focused on the behavior risk factors, together with vaginal fluid pH measurement, wet mount microscopy, detection of Chlamydia trachomatis, and Trichomonas vaginalis were performed. After colposcopy, high-grade abnormalities were detected via direct biopsies and treated with conization procedure. Conuses were immuno-stained with CAIX antibody. The histological findings were CIN1 (n = 14), and CIN2+ (included CIN2 (n = 10), CIN3 (n = 49), and cancer (n = 7; squamous cell carcinomas)). Prevalence of bacterial vaginosis (BV) was similar between the groups. Moderate or severe aerobic vaginitis (msAV) was diagnosed more often among CIN2+ (53.0%) than CIN1 (21.4%). Moderate or strong immunostaining of CAIX (msCAIX) was not detected among CIN1 cases. Thus, msAV was prevalent in CAIX non-stained group (p = 0.049) among CIN2 patients. Co-location of msAV and msCAIX was found in CIN3. Regression model revealed that msAV associated with high-grade cervical intraepithelial neoplasia independently from smoking and the number of partners.

Quality control and external quality assessment for the independent clinic-based evaluation of point-of-care testing to detect Chlamydia trachomatis, Neisseria gonorrhoeae and Trichomonas vaginalis in eight countries

BackgroundSexually transmitted infections caused by Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and Trichomonas vaginalis (TV) remain significant global health problems. The World Health Organization (WHO) has recently conducted a multi-faceted, multi-country validation study (ProSPeRo), which included an evaluation of the Xpert CT/NG and Xpert TV assays on the GeneXpert system (Cepheid, Sunnyvale, Ca., USA) in clinic-based settings across eight countries. To support the study, a training and quality management system was implemented and evaluated.MethodsA comprehensive training program for the study was developed. Quality control (QC) and external quality assessment (EQA) samples were provided by an accredited quality assurance provider. QC testing was conducted at 14 point-of-care testing (POCT) clinics, while EQA samples were tested by the POCT sites and a reference laboratory supporting each clinic.ResultsFor QC testing, concordance with the expected results for CT and NG was > 99% and rates of unsuccessful tests were < 4%. For TV testing, concordance was similar (97%), but rates of unsuccessful tests were high (18%), particularly in the ‘TV negative’ sample. For EQA testing initially conducted in 2018, concordance was 100% for CT and NG, and 90% for TV for the reference laboratory group (which used non-GeneXpert systems). Concordance for the POCT group was also high (> 94%) for all analytes, but this cohort (which used GeneXpert systems) exhibited a high rate of unsuccessful TV tests. All but one of these unsuccessful tests was subcategorised as ‘invalid’.ConclusionsThe high level of concordance for QC and EQA testing confirm that the trained operators at the POC clinical sites were competent to conduct POC testing and that the training and quality systems implemented for the ProSPeRo study were effective. The quality materials used were satisfactory for CT and NG but exhibited poor performance for TV testing on the GeneXpert system. The WHO should continue to work with industry and EQA providers to provide improved materials that are reliable, stable and cost effective for quality management, as it seeks to rollout molecular-based STI POCT in non-laboratory-based settings.Trial registrationEthics approval to conduct the ProSPeRo study was granted by the WHO Ethics Review Committee.

Patterns of Chlamydia trachomatis and Neisseria gonorrhoeae in different anatomical sites among Pre-Exposure Prophylaxis (PrEP) users in Brazil

BackgroundThe presence of untreated sexually transmitted infections (STIs) significantly increases the chance of acquiring HIV. In Brazil, testing for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) among Pre-Exposure Prophylaxis (PrEP) users is insufficient, and syndromic treatment is a priority in clinical practice. Multi-site testing for CT/NG improves thescreening of asymptomatic cases and ensures timely treatment. Therefore, it is essential for HIV prevention. This study aims to test the importance of two-site testing for better screening of these pathogens and to determine whether the presence of symptoms is an indicator of CT/NG infection.MethodsThis is a cross-sectional study carried out in four public infectious diseases clinics in São Paulo State, Brazil between January of 2022 and March of 2023. All participants had an anal swab and a first-pass or mid-stream urine collected for CT/NG analysis by Polymerase chain reaction (PCR). Data about sociodemographic, sexual behavioural and clinical aspects were collected. Pathway analysis was used to examine the direct and indirect relationships between variables according to the theoretical model.ResultsWe screened 171 PrEP users which had two samples collected, resulting in 342 samples. Comparing the anatomic sites, the urine samples showed lower sensitivity for CT and NG than anal samples. Gonorrhoea was directly linked to lower age (β= -0.161, p = 0.001). Time of PrEP use was directly associated with CT infection (β = 0.202; p = 0.042) and inversely associated with dysuria (β= -0.121, p = 0.009). Lower occurrence of yellow-green secretion was linked to detection of CT (β= -0.089, p = 0.005) and NG (β= -0.048, p = 0.002) infections. Foul-smelling discharge was directly associated with CT (β = 0.275, p = 0.004) and NG (β = 0.295, p = 0.037) infection.ConclusionThe symptoms are a bad indicator of CT and NG infection, and the screening must be done in more than one site since most of the positive results would be missed if only urines were tested. In the case of testing only one anatomical site, specifically the urethra, the CT/NG incidence and prevalence would be underestimated. The two-sites testing improves detection rates of CT/NG, and PrEP follow-up benefits people offering STI testing.

Analytical and clinical validation of a multiplex PCR assay for detection of Neisseria gonorrhoeae and Chlamydia trachomatis including simultaneous LGV serotyping on an automated high-throughput PCR system.

For effective infection control measures for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG), a reliable tool for screening and diagnosis is essential. Here, we aimed to establish and validate a multiplex PCR assay on an automated system using a dual-target approach for the detection of CT/NG and differentiation between lymphogranuloma venereum (LGV) and non-LGV from genital and extra-genital specimens. Published primer/probe sets (CT: pmpH, cryptic plasmid; NG: porA, opa) were modified for the cobas 5800/6800/8800. Standards quantified by digital PCR were used to determine linearity and lower limit of detection (LLoD; eSwab, urine). For clinical validation, prospective samples (n = 319) were compared with a CE-marked in vitro diagnostics (CE-IVD) assay. LLoDs ranged from 21.8 to 244 digital copies (dcp)/mL and 10.8 to 277 dcp/mL in swab and urine, respectively. A simple linear regression analysis yielded slopes ranging from -4.338 to -2.834 and Pearson correlation coefficients from 0.956 to 0.994. Inter- and intra-run variability was <0.5 and <1 cycle threshold (ct), respectively. No cross-reactivity was observed (n = 42). Clinical validation showed a sensitivity of 94.74% (95% confidence interval (CI): 87.23%-97.93%) and 95.51% (95% CI: 89.01%-98.24%), a specificity of 99.59% (95% CI: 97.71%-99.98%) and 99.57% (95% CI: 97.58%-99.98%), positive predictive values of 89.91% (estimated prevalence: 3.7%; 95% CI: 80.91%-95.6%) and 88.61% (estimated prevalence: 3.4%; 95% CI: 80.18%-94.34%), and negative predictive values of 99.81% (95% CI: 98.14%-100%) and 99.85% (95% CI: 98.14%-100%) for the detection of CT and NG, respectively. In conclusion, we established a dual-target, internally controlled PCR on an automated system for the detectiwon of CT/NG from genital and extra-genital specimens. Depending on local regulations, the assay can be used as a screening or a confirmatory/typing assay.IMPORTANCEChlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) represent a major global health burden, with the World Health Organization estimating that >128 million and >82 million people, respectively, were newly infected in 2020. For effective infection control measures, a reliable tool for sensitive diagnosis and screening of CT/NG is essential. We established a multiplex PCR assay for the detection of CT/NG and simultaneous discrimination between lymphogranuloma venereum (LGV) and non-LGV strains, which has been validated for genital and extra-genital specimens on a fully automated system. To increase assay sensitivity, a dual-target approach has been chosen for both pathogens. This strategy reduces false-positive results in oropharyngeal swabs due to the detection of commensal N. species that may harbor NG DNA fragments targeted in the PCR due to horizontal gene transmission following previous infection. In sum, the established assay provides a powerful tool for use as either a screening/diagnostic or a typing/confirmatory assay.

Progress in research of self-sampling for detection of genital chlamydia trachomatis and related factors in men who have sex with men

Laboratory testing is a vital chain in the prevention and control of genital chlamydia trachomatis infection. The prevalence of genital chlamydia trachomatis infection is high, but the detection rate of the infection is low in men who have sex with men (MSM) in China. Self-sampling for genital chlamydia trachomatis detection by MSM is a new option to address this problem, which would play a significant role in expanding genital chlamydia trachomatis infection screening in this population. This paper summarizes the progress in research of self-sampling for the detection of genital chlamydia trachomatis and the related factors in MSM both at home and abroad to provide reference for the promotion of self-sampling for the detection of genital chlamydia trachomatis in this population.

Multi-repeat sequences identification using genome mining techniques for developing highly sensitive molecular diagnostic assay for the detection of Chlamydia trachomatis

Chlamydia trachomatis (C. trachomatis) is a common sexually transmitted infection (STI). In 2019, the World Health Organization reported about 131 million infections. The majority of infected patients are asymptomatic with cases remaining undetected. It is likely that missed C. trachomatis infections contribute to preventable adverse health outcomes in women and children. Consequently, there is an urgent need of developing efficient diagnostic methods. In this study, genome-mining approaches to identify identical multi-repeat sequences (IMRS) distributed throughout the C. trachomatis genome were used to design a primer pair that would target regions in the genome. Genomic DNA was 10-fold serially diluted (100pg/mL to 1×10-3pg/mL) and used as DNA template for PCR reactions. The gold standard PCR using 16S rRNA primers was also run as a comparative test, and products were resolved on agarose gel. The novel assay, C. trachomatis IMRS-PCR, had an analytical sensitivity of 4.31 pg/µL, representing better sensitivity compared with 16S rRNA PCR (9.5 fg/µL). Our experimental data demonstrate the successful development of lateral flow and isothermal assays for detecting C. trachomatis DNA with potential use in field settings. There is a potential to implement this concept in miniaturized, isothermal, microfluidic platforms, and laboratory-on-a-chip diagnostic devices for reliable point-of-care testing.

A national network of molecular tests to detect Chlamydia trachomatis and Neisseria gonorrhoeae: a pilot implementation experience in Brazil

This study aimed to know the opinion of professionals participating in an experiment to implement a pilot for molecular tests to detect Chlamydia trachomatis and Neisseria gonorrhoeae at the Brazilian Unified National Health System (SUS). The detection rate of C. trachomatis and/or N. gonorrhoeae and the factors associated with infection were determined. The strategy included laboratories belonging to the HIV and viral hepatitis viral load network. Testing targeted people who are more vulnerable to sexually transmitted infections and collected urine samples and/or vaginal, endocervical, and/or male urethral swabs. Questionnaires were sent to state managers and laboratory professionals about the implementation of the pilot. Reviews were overall positive. Weaknesses included difficulties changing work processes, lack of human resources, poorly sensitized care professionals, and absence of primary urine tubes, the only input not provided. Strengths included the centralized acquisition of tests, sharing of equipment, and storage of samples at room temperature. Of the 16,177 people who were tested, 1,004 (6.21%) were positive for C. trachomatis; 1,036 (6.4%), for N. gonorrhoeae; and 239 (1.48%), for C. trachomatis/N. gonorrhoeae . Detection of any infection occurred more frequently in young people (≤ 24 vs. > 24 years) (adjOR = 2.65; 95%CI: 2.38-2.96), men (adjOR = 1.95; 95%CI: 1.72-2.21), brown/black individuals (adjOR = 1.06; 95%CI: 1.05-1.11), those in Southeastern Brazil (adjOR = 1.08; 95%CI: 1.02-1.13), and in urethral secretion samples (adjOR = 1.46; 95%CI: 1.41-1.52). Results show the importance of making testing available nationwide, which supported the implementation of a definitive network to detection C. trachomatis/N. gonorrhoeae in SUS.

Sero-Prevalence of Chlamydia trachomatis among HIV Patients and Healthy Female Volunteers in Port-Harcourt, Rivers State, Nigeria

Background: Chlamydios is caused by the bacterium Chlamydia trachomatis is the most prevalent bacterial Sexually Transmitted Infections (STI) known to cause damage to a woman’s reproductive organs. The study was undertaken to determine the sero-prevalence of chlamydiosis among HIV patients and Healthy female volunteers in Port-Harcourt. The prevalence of chlamydiosis was investigated among 250 (150 HIV patients, and 100 Healthy volunteers) consented women of reproductive age attending Rivers State University Teaching Hospital in Port-Harcourt, Rivers State. Enzyme Linked Immunosorbent assay technique was performed to detect Chlamydia trachomatis IgG antibodies. The overall sero-prevalence of C. trachomatis in the among healthy volunteers was 10%, while that of HIV patents was 12.7%. HIV patients who were above 35 years accounted for 16% of the disease distribution. When prevalence was evaluated with the subgroups, there was no significant difference of Chlamydia trachomatis IgG antibodies across the subgroups (P&gt;0.05). There was no association between socio-demographic factors and sero-prevalence of chlamydiosis. The possible risk factor for chlamydiosis base on life style was lack of screening for Chlamydia trachomatis (P&lt;0.05) as a result of limited awareness of the infection by majority of the participants. Chlamydiosis is largely under diagnosed in the population. Therefore every sexually active woman irrespective of age is expected to undergo screening for chlamydia infection.

Impact of improper sample handling on Cobas CT/NG testing platform with dual swab sample collection kit for detecting Chlamydia trachomatis and Neisseria gonorrhoeae.

The importance of this observation lies in its potential to directly impact testing outcomes and patient care. By identifying improper sample handling as a contributing factor to a substantial number of invalid results, we emphasize the need for meticulous adherence to recommended protocols during sample collection. Laboratories that overlook or are unaware of such deviations may inadvertently compromise the reliability and efficacy of their diagnostic processes, leading to misdiagnoses, delayed treatment, and patient dissatisfaction.

An isothermal CRISPR-based diagnostic assay for Neisseria gonorrhoeae and Chlamydia trachomatis detection.

The occurrence of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) is increasing worldwide, particularly in low- and middle-income countries. In cases where most infections are asymptomatic and remain in a coinfection condition. It may cause missed detections or the severe subsequent symptoms. Accurate diagnosis and convenient screening are essential for disease control. However, molecular diagnostics for CT/NG predominantly rely on polymerase chain reaction (PCR)-based detection, which requires special devices and conditions. Here, we developed an isothermal CRISPR-based CT/NG dual-target detection system by pairing recombinase polymerase amplification (RPA) and CRISPR-Cas12a/13a detection. Multiplex RPA can amplify NG and CT simultaneously, and a single-pot reaction with the Cas12a/13a can be performed for further recognizing the amplified target, driving the cleavage of the corresponding fluorescence reporter separately; thus, the signal can be monitored in different channels. This CRISPR-based CT/NG detection system achieved analytical sensitivities of 10° copies/μL for both synthetic CT/NG dsDNA and exhibited no cross-reaction with other species. In tests on 88 clinical samples, our CRISPR-based assay showed excellent agreement with the commercial assay Roche Cobas 4800 (100% accuracy for NG, 94.32% accuracy for CT, and 97.73% accuracy for CT/NG coinfection) and showed higher positive percent agreement, negative percent agreement, and accuracy than those reported for TaqMan PCR in a previous study. In addition, the results of this CRISPR-based system could be acquired within 75 min. Our isothermal diagnostic method with promising performance provides more convenience than PCR-based methods for detection and screening.IMPORTANCEA method for Neisseria gonorrhoeae (NG)/Chlamydia trachomatis (CT) detection is developed using multiplex-recombinase polymerase amplification and Cas12a/Cas13a. This method can detect NG and CT simultaneously with high sensitivity and specificity. This method has great potential to be further developed into larger-scale screening and point-of-care testing (POCT).

Highly-Specific Single-Stranded Oligonucleotides and Functional Nanoprobes for Clinical Determination of Chlamydia Trachomatis and Neisseria Gonorrhoeae Infections.

Early detection of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) is the key to controlling the spread of these bacterial infections. An important step in developing biosensors involves identifying reliable sensing probes against specific genetic targets for CT and NG. Here, the authors have designed single-stranded oligonucleotides (ssDNAs) targeting mutually conserved genetic regions of cryptic plasmid and chromosomal DNA of both CT and NG. The 5'- and 3'- ends of these ssDNAs are differentially functionalized with thiol groups and coupled with gold nanoparticles (AuNP) to develop absorbance-based assay. The AuNPs agglomerate selectively in the presence of its target DNA sequence and demonstrate a change in their surface plasmon resonance. The optimized assay is then used to detect both CT and NG DNA extracted from 60 anonymized clinical samples with a clinical sensitivity of ∼100%. The limit of detection of the assays are found to be 7 and 5 copies/µL for CT and NG respectively. Furthermore, it can successfully detect the DNA levels of these two bacteria without the need for DNA extraction and via a lateral flow-based platform. These assays thus hold the potential to be employed in clinics for rapid and efficient monitoring of sexually transmitted infections.

Pooled Pharyngeal, Rectal, and Urine Specimens for the Point-of-Care Detection of Chlamydia trachomatis and Neisseria gonorrhoeae by Lay Providers in Key Population-Led Health Services in Thailand.

Routine testing for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) in people with heightened risk is lacking in Thailand. This study aimed to assess the performance of the Cepheid Xpert CT/NG assay, conducted by key population (KP) lay providers, for CT and NG detection on single-site and pooled specimens from the pharynx, rectum, and urine. Between August and October 2019, 188 men who have sex with men and 11 transgender women were enrolled. Participants collected urine specimens while trained KP lay providers obtained pharyngeal and rectal swabs. Compared to single-site testing with the Abbott RealTime CT/NG assay by medical technologists, the Xpert assay missed one pharyngeal NG infection out of 199 single-site specimens, giving a 93.3% sensitivity for pharyngeal NG and one missed pharyngeal NG infection out of fifty pooled specimens, giving an 88.9% sensitivity for pharyngeal NG. There was no discrepancy between the two assays for CT detection. The Cohen's Kappa coefficient of pooled specimen testing by the Xpert was 0.93 for NG and 1 for CT when compared to single-site testing by Abbott. Implementing pooled specimen testing by KP lay providers can be a cost-saving strategy to enhance the uptake of CT/NG services for populations facing increased risk.

A-363 Evaluating the Performance of Emerging STI Point of Care Assays Using Novel, Room Temperature Stable CT/NG/TV/MG Positive Swab Quality Control Materials

Abstract Background The emergence of Point of Care tests that detect Sexually Transmitted Infections (STIs) is critical for screening and diagnostic programs in low-resource settings. Point of Care tests that are designed to simultaneously detect Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Trichomonas vaginalis (TV), and Mycoplasma genitalium (MG) promote rapid diagnosis and early treatment of the most common etiological agents causing STIs. Along with the roll-out and use of these tests, there is a growing need for complex multi-analyte quality control materials that are stable at room temperature and challenge test performance by identifying result deviations, lot-to-lot variability, and routine laboratory workflow errors. Microbix developed a whole-workflow multiplex quality control desiccated on a Copan FLOQSwab® that is stable at 2–30°C and contains inactivated whole-genome target pathogens. The objective of this study is to evaluate sample performance with multiple Point of Care diagnostic platforms that are currently in development and commercial IVD tests that are routinely used in the laboratory. Methods Microbix designed an inactivated STI whole-workflow control that contains whole-genome CT, NG, TV, MG, and human cells to satisfy sample adequacy control requirements. The formulation is desiccated on a Copan FLOQSwab® to mimic patient specimen formats and ensure sample compatibility with all assay workflows and elution buffers. Sample performance was evaluated with Cepheid Xpert® CT/NG assay, Cepheid Xpert® TV assay, Abbott Alinity m STI assay, BD MAX™ CT/GC/TV assay, Seegene Novaplex™ CT/NG/TV/MG assay, EliTechGroup STI PLUS ELITe MGB®Kit, and commercial Point of Care assays currently in development. Results The STI positive swab formulation demonstrated acceptable performance when tested with various nucleic acid amplification tests that detect CT, NG, TV, and MG targets. The formulations also behaved as useful quality management tools by highlighting design limitations for commercial Point of Care assays that are currently in development. Conclusion CT/NG/TV/MG whole-genome multiplex formulation desiccated on a Copan FLOQSwab® is an advantageous prospective quality control material that is stable at room temperature and supports the clinical use and accuracy of emerging STI assays, including the most challenging Point of Care test formats. The formulations showed acceptable performance on multiple platforms, demonstrating excellent commutability. Additionally, the dry swab format offers great practicality for monitoring assay performance in low-resource settings.