scholarly journals Meta-analysis of the Cepheid Xpert® CT/NG assay for extragenital detection of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections

Sexual Health ◽  
2019 ◽  
Vol 16 (4) ◽  
pp. 314 ◽  
Author(s):  
Claire C. Bristow ◽  
Sheldon R. Morris ◽  
Susan J. Little ◽  
Sanjay R. Mehta ◽  
Jeffrey D. Klausner

Background Most studies evaluating extragenital testing performance for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) detection by the Xpert® CT/NG show high per cent agreement with comparison assays; however, the precision around positive per cent agreement is low and thus the values that have been reported are not highly informative. Therefore, a systematic review was conducted and data from five studies were combined to better assess positive per cent agreement. Methods: The literature indexed on PubMed.gov was searched. Included studies were those that were an evaluation of the Xpert CT/NG assay with rectal and/or pharyngeal specimen types compared with another nucleic acid amplification test (NAAT), the Aptima transcription mediated amplification assay. A full Bayesian method was used for bivariate fixed-effect meta-analysis of positive and negative per cent agreement and pooled estimates (and 95% confidence intervals (CI)) were presented for each. Results: The pooled positive and negative per cent agreement for detection of CT in rectal specimens was 89.72% (95% CI: 84.97%, 93.64%) and 99.23% (95% CI: 98.74%, 99.60%), and in pharyngeal specimens, they were 89.96% (95% CI: 66.38%, 99.72%) and 99.62% (95% CI: 98.95%, 99.95%) respectively. For NG detection in rectal specimens, the pooled positive and negative per cent agreement was 92.75% (95% CI: 87.91%, 96.46%) and 99.75% (95% CI: 99.46%, 99.93%), and in pharyngeal specimens, they were 92.51% (95% CI: 85.84%, 97.18%) and 98.56% (95% CI: 97.69%, 99.23%) respectively. Conclusions: It was found that the Xpert CT/NG assay performed similarly to the Aptima transcription mediated amplification assay for the detection of CT and NG in extragenital specimens. The Xpert assay has the benefit of providing faster results at the point-of-care, thus reducing the turnaround time for results, potentially enabling same-day treatment.

Author(s):  
Paul C. Adamson ◽  
Jeffrey D. Klausner

Chlamydia trachomatis and Neisseria gonorrhoeae are two of the most often reported bacterial infections in the United States. The rectum and oropharynx are important anatomic sites of infection and can contribute to ongoing transmission. Nucleic acid amplification tests (NAATs) are the mainstays for the detection of C. trachomatis and N. gonorrhoeae infections owing to their high sensitivity and specificity. Several NAATs have been evaluated for testing in rectal and pharyngeal infections. A few assays recently received clearance by the Food and Drug Administration, including one point-of-care test. Those assays can be used for testing in symptomatic individuals, as well as for asymptomatic screening in certain patient populations. Routine screening for C. trachomatis in pharyngeal specimens is not recommended by the Centers for Disease Control and Prevention, though is often performed due to the use of multiplex assays. While expanding the types of settings for screening and using self-collected rectal and pharyngeal specimens can help to increase access and uptake of testing, additional research is needed to determine the potential benefits and costs associated with increased screening for rectal and pharyngeal C. trachomatis and N. gonorrhoeae infections on a population level.


Author(s):  
Yan Han ◽  
Mei-Qin Shi ◽  
Qing-Ping Jiang ◽  
Wen-Jing Le ◽  
Xiao-Lin Qin ◽  
...  

BackgroundWe aimed to evaluate the clinical performance of the GeneXpert® (Xpert) CT/NG assay for the detection of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) using urine and cervical swabs collected from patients in China.MethodsThis study was conducted from September 2016 to September 2018 in three Chinese urban hospitals. The results from the Xpert CT/NG test were compared to those from the Roche cobas® 4800 CT/NG test. Discordant results were confirmed by DNA sequence analysis.ResultsIn this study, 619 first void urine (FVU) specimens and 1,042 cervical swab specimens were included in the final dataset. There were no statistical differences between the results of the two tests for the detection of CT/NG in urine samples (p > 0.05), while a statistical difference was found in cervical swabs (p < 0.05). For CT detection, the sensitivity and specificity of the Xpert test were 100.0% (95%CI = 96.8–99.9) and 98.3% (95%CI = 96.6–99.2) for urine samples and 99.4% (95%CI = 96.5–100.0) and 98.6% (95%CI 97.5–99.2) for cervical swabs, respectively. For NG detection, the sensitivity and specificity of the Xpert test were 99.2% (95%CI = 94.9–100.0) and 100.0% (95%CI = 99.0–100.0) for urine and 100% (95%CI = 92.8–100.0) and 99.7% (95%CI = 99.0–99.9) for cervical swabs, respectively.ConclusionThe Xpert CT/NG test exhibited high sensitivity and specificity in the detection of CT and NG in both urine and cervical samples when compared to the reference results. The 90-min turnaround time for CT and NG detection at the point of care using Xpert may enable patients to receive treatment promptly.


Sexual Health ◽  
2020 ◽  
Vol 17 (4) ◽  
pp. 359 ◽  
Author(s):  
Sara F. E. Bell ◽  
Luke Coffey ◽  
Joseph Debattista ◽  
Steven G. Badman ◽  
Andrew M. Redmond ◽  
...  

Abstract Background The advent of fully automated nucleic acid amplification test (NAAT) technology brings new public health opportunities to provide Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) point-of-care testing (POCT) in non-traditional settings. Methods: This pilot study evaluated the integration of the CT/NG Xpert diagnostic assay into an urban peer-led community setting providing HIV and syphilis POCT. A comprehensive protocol of testing, result notification, referral and follow up, managed by peer test facilitators, was undertaken. Results: Over 67 weeks, there were 4523 occasions of CT/NG testing using urine, oropharyngeal and anorectal samples with 25.7% (803) of the 3123 unique participants returning for repeat testing. The prevalence of CT and NG was 9.5% and 5.4% respectively. Where CT and or NG infection was detected, 98.4% (604/614) of participants were successfully notified of detected infection and referred for treatment. Evaluation Survey responses (11.4%, 516/4523) indicated a substantial proportion of respondents (27.1%, 140/516) ‘would not have tested anywhere else’. Of note, 17.8% (92/516) of participants reported no previous CT/NG test and an additional 17.8% (92/516) reported testing more than 12 months ago. A total of 95.9% (495/516) of participants ‘Strongly agreed’ or ‘Agreed’ to being satisfied with the service. Conclusion: The project successfully demonstrated an acceptable and feasible model for a peer-delivered community-led service to provide targeted molecular CT/NG POCT. This model offers capacity to move beyond the traditional pathology and STI testing services and establish community-led models that build trust and increase testing rates for key populations of epidemiological significance.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Radhika Biyani ◽  
Kirti Sharma ◽  
Kenji Kojima ◽  
Madhu Biyani ◽  
Vishnu Sharma ◽  
...  

AbstractSimple tests of infectiousness that return results in minutes and directly from samples even with low viral loads could be a potential game-changer in the fight against COVID-19. Here, we describe an improved isothermal nucleic acid amplification assay, termed the RICCA (RNA Isothermal Co-assisted and Coupled Amplification) reaction, that consists of a simple one-pot format of ‘sample-in and result-out’ with a primary focus on the detection of low copy numbers of RNA virus directly from saliva without the need for laboratory processing. We demonstrate our assay by detecting 16S rRNA directly from E. coli cells with a sensitivity as low as 8 CFU/μL and RNA fragments from a synthetic template of SARS-CoV-2 with a sensitivity as low as 1740 copies/μL. We further demonstrate the applicability of our assay for real-time testing at the point of care by designing a closed format for paper-based lateral flow assay and detecting heat-inactivated SARS-COV-2 virus in human saliva at concentrations ranging from 28,000 to 2.8 copies/μL with a total assay time of 15–30 min.


2019 ◽  
Vol 19 (1) ◽  
Author(s):  
André Frontzek ◽  
Gudrun Aretzweiler ◽  
Daniela Winkens ◽  
Dana Duncan ◽  
Elizabeth M. Marlowe

Abstract Background The global burden of sexually transmitted infections (STIs) is high and there have been reports of increasing chlamydial and gonorrheal infections. High-volume screening programs for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are an important component of STI control. This study evaluated the high-volume workflow and performance of the cobas® CT/NG assay for use on the automated Roche cobas® 6800 system, with the cobas p 480 instrument for pre-analytics, compared with the Aptima Combo 2 assay on the Hologic Panther system. Methods High-volume workflow and performance were evaluated using paired female urine specimens. Workflow analysis (n = 376) included hands-on time (HoT), number of manual interventions, and time to first and last results. For performance assessment, paired results from the cobas CT/NG and Aptima Combo 2 assays, for both CT and NG, were compared and two-sided 95% confidence intervals calculated to provide estimates of positive percent agreement (PPA), negative percent agreement (NPA), and overall percent agreement (OPA) between the tests. McNemar’s test was used for significance testing. Results Pre-analytical preparations and system start-up on the cobas 6800 system required 00:27:38 (hr:min:sec) HoT whilst the Panther system required 00:30:43. The cobas 6800 system required eight interactions and 00:43:59 HoT to process 376 samples. The Panther system required six interactions and 00:39:10 HoT. Time to first results was 02:53:00 on the cobas c6800 system for 96 samples and 03:28:29 on the Panther system for five samples. The cobas 6800 system delivered all 376 results 3 h faster than the Panther system (07:45:26 and 10:47:30, respectively). The performance correlation between both assays was high (PPA, NPA and OPA > 99% for both CT and NG). McNemar’s test revealed no statistically significant difference between the assays. Conclusion For high-volume automated CT/NG testing, both the cobas 6800 system and Panther system provided accurate results. Although less manual intervention steps were needed for the Panther system, improved turnaround time was obtained with the cobas 6800 system with less risk for contamination. The additional testing capacity on the cobas 6800 system would allow a growing service to deliver more results in a single shift.


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