Geiger R, Smith D M, Little S J, Mehta S R
Department of Medicine, University of California San Diego, USA.
Department of Medicine, University of California San Diego, USA; Department of Medicine, San Diego Veterans Affairs Medical Center, USA.
Austin J HIV AIDS Res. 2016;3(1). Epub 2016 Mar 1.
The GeneXpert CT/NG (Cepheid, Sunnyvale, CA) assay is a point-of-care (POC) molecular diagnostic assay designed to rapidly test for the presence of Chlamydia trachomatis (CT) and (GC). However, the test is only approved for vaginal swabs, urine, and endocervical swabs. Here, we performed an evaluation of the GeneXpert CT/NG assay to detect the presence of CT and GC on male pharyngeal and rectal swabs.
Men who have sex with men participating in an HIV and Sexually Transmitted Infection (STI) screening program providing consent were enrolled into the study. Participants were asked to self-collect two pharyngeal and two rectal swabs. One set was tested on site using GeneXpert and the other was sent to a reference lab for molecular testing using the APTIMA system (Hologic, San Diego, CA).
A total of 570 swabs were collected from 144 patients. GeneXpert detected 13/15 rectal swabs testing CT positive by the APTIMA assay (relative sensitivity=88.2%), 1/2 pharyngeal swabs testing CT positive (relative sensitivity=50%), and 7/9 pharyngeal swabs testing NG positive (relative sensitivity =77.8%). No discordance was observed for rectal NG swabs.
Although less sensitive than the APTIMA assay for the molecular detection of NG and CT, GeneXpert's potential as a rapid POC diagnostic still make it a viable diagnostic test for STI screening. Molecular POC diagnostics, such as this, will allow more thorough screening of at risk individuals, and enhance the ability of clinics to provide same-day diagnosis and treatment.
GeneXpert CT/NG检测法（赛沛公司，加利福尼亚州桑尼维尔市）是一种即时检验（POC）分子诊断检测法，旨在快速检测沙眼衣原体（CT）和淋病奈瑟菌（GC）的存在。然而，该检测仅批准用于阴道拭子、尿液和宫颈拭子检测。在此，我们对GeneXpert CT/NG检测法进行了评估，以检测男性咽部和直肠拭子中CT和GC的存在情况。
参与HIV和性传播感染（STI）筛查项目并提供同意书的男男性行为者被纳入研究。参与者被要求自行采集两根咽部拭子和两根直肠拭子。一组样本在现场使用GeneXpert进行检测，另一组则送往参考实验室，使用APTIMA系统（豪洛捷公司，加利福尼亚州圣地亚哥市）进行分子检测。
共从144名患者中采集了570份拭子。GeneXpert检测出15份经APTIMA检测CT呈阳性的直肠拭子中的13份（相对灵敏度=88.2%），2份CT呈阳性的咽部拭子中的1份（相对灵敏度=50%），以及9份NG呈阳性的咽部拭子中的7份（相对灵敏度=77.8%）。直肠NG拭子未观察到不一致情况。
尽管在分子检测NG和CT方面不如APTIMA检测法敏感，但GeneXpert作为一种快速即时诊断方法的潜力使其仍然是STI筛查的可行诊断测试。这样的分子即时诊断方法将允许对高危个体进行更全面的筛查，并提高诊所提供当日诊断和治疗 的能力。
