Background Sexually transmitted infections (STIs) are one of the most common communicable diseases worldwide and are associated with significant morbidity and mortality. Data indicates that the four curable STIs - chlamydia, gonorrhea, trichomoniasis, and syphilis - cause over 375 million infections annually. Further, the infection rate for gonorrhea has increased by 63% in the United States and the emergence of resistant gonorrhea is an urgent global public health concern. To prevent transmission of gonorrhea and other curable STIs and minimize the escalation of untreated infections, early and effective prevention and control strategies are paramount. Rapid diagnostic testing and nucleic acid amplification tests (NAATs) have become the gold standard for STI detection. However, limited global access to these technologies often requires that samples be shipped to central laboratories for analysis. Current protocols recommend that neat urine be analyzed within 24 hours of collection if stored at 2 °C to 8 °C or within four days if frozen, as prolonged storage and exposure to freeze-thaws can induce cell lysis and release of nucleases, leading to degradation of DNA and false negative test results. Without sample stabilization, laboratories are left with a small window for accurate analysis. Here, we demonstrate that Streck Urine Preserve (SUP) maintains target and donor DNA concentrations during prolonged storage and that these stabilized samples are compatible with Cepheid’s automated GeneXpert System and associated Xpert CT/NG test. Methods Fresh human urine, with or without SUP, was tested neat or spiked with Neisseria gonorrhoeae (N. gonorrhoeae). Samples were stored at room temperature for up to 18 days before being analyzed on the Cepheid GeneXpert System using the Xpert CT/NG test per manufacturer’s instructions. Differences in average Ct values were compared for the sample processing control, sample adequacy control, and N. gonorrhoeae targets. DNA stability was assessed by comparing the changes between fresh and SUP-treated samples throughout the study period. Results Following prolonged storage, Ct values for neat, untreated urine increased by 3-7 cycles, correlating to a 10- to 100-fold decrease in detectable copies of N. gonorrhoeae and the sample adequacy control compared to urine samples stabilized with SUP. The average Ct value for samples stabilized with SUP did not change by more than 1.5 cycles throughout the study period. Additionally, Ct values for the sample processing control remained constant throughout the testing period, indicating that SUP did not impact sample processing. Conclusions When limited point-of-care testing options require storage and shipping of samples to central laboratories, urine stabilizers are imperative to obtain results representative of the patient sample at the time of collection. SUP effectively stabilized N. gonorrhoeae DNA and donor DNA prior to analysis with the Cepheid Xpert CT/NG test. This contrasts with the marked decrease in DNA copy number in non-stabilized urine over the study duration, which may lead to false negative results for low-positive urine samples. Taken together, SUP provides clinical researchers and assay developers with added flexibility when handling, shipping, and processing urine specimens and supports compatibility with automated NAAT systems and tests.

中文翻译：

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A-296 Streck 尿液保存液为 Cepheid Xpert CT/NG 测试提供样品稳定性


背景 性传播感染（STI）是世界范围内最常见的传染病之一，与显着的发病率和死亡率相关。数据表明，四种可治愈的性传播感染——衣原体、淋病、滴虫病和梅毒——每年导致超过 3.75 亿人感染。此外，美国的淋病感染率增加了63%，耐药性淋病的出现是全球紧迫的公共卫生问题。为了防止淋病和其他可治愈的性传播感染的传播并最大限度地减少未经治疗的感染的升级，早期有效的预防和控制策略至关重要。快速诊断检测和核酸扩增检测（NAAT）已成为性传播感染检测的黄金标准。然而，全球对这些技术的获取有限，通常需要将样品运送到中心实验室进行分析。目前的方案建议，如果储存在 2°C 至 8°C 下，则应在收集后 24 小时内对纯尿液进行分析，如果冷冻则应在四天内进行分析，因为长时间储存​​和暴露于冻融环境会诱导细胞裂解和核酸酶释放，从而导致DNA 降解和假阴性检测结果。如果没有样品稳定性，实验室进行准确分析的窗口就很小。在这里，我们证明 Streck 尿液保存 (SUP) 在长期储存过程中可保持靶标和供体 DNA 浓度，并且这些稳定的样品与 Cepheid 的自动化 GeneXpert 系统和相关的 Xpert CT/NG 测试兼容。方法 新鲜人尿液，无论是否含有 SUP，均对纯尿液或添加淋病奈瑟氏菌 (N. gonorrhoeae) 进行测试。 样品在室温下保存长达 18 天，然后按照制造商的说明使用 Xpert CT/NG 测试在 Cepheid GeneXpert 系统上进行分析。比较了样品处理对照、样品充足性对照和淋病奈瑟菌目标的平均 Ct 值的差异。通过比较整个研究期间新鲜样品和 SUP 处理样品之间的变化来评估 DNA 稳定性。结果 长时间储存​​后，与 SUP 稳定的尿液样本相比，未经处理的纯净尿液的 Ct 值增加了 3-7 个周期，这与可检测到的淋病奈瑟菌拷贝数和样本充足性对照减少了 10 至 100 倍相关。在整个研究期间，用 SUP 稳定的样品的平均 Ct 值变化不超过 1.5 个周期。此外，样品处理对照的 Ct 值在整个测试期间保持恒定，表明 SUP 不会影响样品处理。结论 当有限的即时检测选项需要储存样本并将其运送到中心实验室时，尿液稳定剂必须在收集时获得代表患者样本的结果。在使用 Cepheid Xpert CT/NG 测试进行分析之前，SUP 有效稳定了淋病奈瑟菌 DNA 和供体 DNA。这与研究期间非稳定尿液中 DNA 拷贝数的显着下降形成鲜明对比，这可能导致低阳性尿液样本出现假阴性结果。总而言之，SUP 为临床研究人员和分析开发人员在处理、运输和处理尿液样本时提供了更大的灵活性，并支持与自动化 NAAT 系统和测试的兼容性。