Influence of storage time on DNA of Chlamydia trachomatis, Ureaplasma urealyticum, and Neisseria gonorrhoeae for accurate detection by quantitative real-time polymerase chain reaction

The shipment and storage conditions of clinical samples pose a major challenge to the detection accuracy of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), and Ureaplasma urealyticum (UU) when using quantitative real-time polymerase chain reaction (qRT-PCR). The aim of the present study was to explore the influence of storage time at 4°C on the DNA of these pathogens and its effect on their detection by qRT-PCR. CT, NG, and UU positive genital swabs from 70 patients were collected, and DNA of all samples were extracted and divided into eight aliquots. One aliquot was immediately analyzed with qRT-PCR to assess the initial pathogen load, whereas the remaining samples were stored at 4°C and analyzed after 1, 2, 3, 7, 14, 21, and 28 days. No significant differences in CT, NG, and UU DNA loads were observed between baseline (day 0) and the subsequent time points (days 1, 2, 3, 7, 14, 21, and 28) in any of the 70 samples. Although a slight increase in DNA levels was observed at day 28 compared to day 0, paired sample t-test results revealed no significant differences between the mean DNA levels at different time points following storage at 4°C (all P>0.05). Overall, the CT, UU, and NG DNA loads from all genital swab samples were stable at 4°C over a 28-day period.

临床样本的运送与储存条件，对采用实时定量聚合酶链反应（quantitative real-time polymerase chain reaction，qRT-PCR）检测沙眼衣原体（Chlamydia trachomatis，CT）、淋病奈瑟菌（Neisseria gonorrhoeae，NG）和解脲脲原体（Ureaplasma urealyticum，UU）的检测准确性构成重大挑战。本研究旨在探究4℃储存时长对上述三种病原体DNA的影响，及其对通过qRT-PCR检测这些病原体的作用。本研究收集了70例患者的CT、NG、UU阳性生殖道拭子样本，提取所有样本的DNA并均分为8份。其中1份即刻通过qRT-PCR分析以评估初始病原体载量，剩余样本置于4℃储存，分别于1、2、3、7、14、21及28天后开展检测。70份样本在基线（第0天）与后续各时间点（第1、2、3、7、14、21、28天）的CT、NG、UU DNA载量均未观察到显著差异。尽管第28天的DNA水平较第0天略有升高，但配对样本t检验结果显示，4℃储存后各时间点的平均DNA水平之间均无统计学显著差异（所有P>0.05）。综上，所有生殖道拭子样本中的CT、UU及NG DNA载量在4℃条件下储存28天期间均保持稳定。