评估埃塞俄比亚西北部阿姆哈拉州五种旋毛虫感染的诊断方法。
Evaluation of five diagnostic methods for Strongyloides stercoralis infection in Amhara National Regional State, northwest Ethiopia.
机构信息
Department of Medical Laboratory Science, College of Medicine and Health Sciences, Bahir Dar University, Bahir Dar, Ethiopia.
Mundo Sano Foundation and Institute of Health Carlos III, Madrid, Spain.
出版信息
BMC Infect Dis. 2022 Mar 28;22(1):297. doi: 10.1186/s12879-022-07299-1.
BACKGROUND
Strongyloides stercoralis is an intestinal parasite that can cause chronic infection, hyperinfection and/or a dissemination syndrome in humans. The use of techniques targeting ova fails to detect S. stercoralis, as only larvae of the parasite are excreted in faeces. Due to the absence of "Gold" standard diagnostic method for S. stercoralis, there is a paucity of reported data worldwide.
OBJECTIVE
This study aimed to evaluate the performance of diagnostic methods of S. stercoralis infection by taking the composite reference as a "Gold" standard.
METHODS
A cross-sectional study was conducted among 844 schoolchildren in Amhara Region, Ethiopia, from April to December 2019. Stool samples were collected and processed with formol-ether concentration technique (FECT), spontaneous tube sedimentation technique (STST), Baermann concentration technique (BCT), agar plate culture (APC) and real-time polymerase chain reaction (RT-PCR). Sensitivity, specificity, positive predictive value, and negative predictive value of each diagnostic method were computed against the composite reference. The agreements of diagnostic methods were evaluated by Kappa value at 95% CI.
RESULTS
The composite detection rate of S. stercoralis by the five diagnostic methods was 39.0% (329/844). The detection rate of the parasite from stool samples by FECT, STST, BCT, APC and RT-PCR was 2.0% (17/844), 4.0% (34/844), 10.2% (86/844), 10.9% (92/844) and 28.8% (243/844), respectively. The highest detection rate (37.8%; 319/844) of S. stercoralis was recorded by a combination of BCT, APC, and RT-PCR followed by a combination of STST, BCT, APC and RT-PCR (37.3%; 315/844). The sensitivity of FECT, STST, BCT, APC and RT-PCR against the composite reference was 5.2%, 10.3%, 26.4%, 28.0% and 73.9%, respectively. The diagnostic agreements of RT-PCR, APC, BCT, STST and FECT with the composite reference in detection of S. stercoralis were substantial (0.775), fair (0.321), fair (0.305), slight (0.123), and slight (0.062), respectively.
CONCLUSION
RT-PCR detected the highest number of S. stercoralis infections. A combination of RT-PCR with APC and/or BCT better detected S. stercoralis from stool samples compared to other combinations or single diagnostic methods. Therefore, RT-PCR and combination of RT-PCR with APC and/or BCT diagnostic methods should be advocated for detection of S. stercoralis infection.
背景
粪类圆线虫是一种肠道寄生虫，可导致人体慢性感染、重度感染和/或播散综合征。针对虫卵的技术无法检测到粪类圆线虫，因为只有寄生虫的幼虫才会在粪便中排出。由于粪类圆线虫缺乏“金标准”诊断方法，因此全球报道的数据很少。
目的
本研究旨在以综合参考为“金标准”，评估粪类圆线虫感染的诊断方法的性能。
方法
2019 年 4 月至 12 月，在埃塞俄比亚阿姆哈拉地区对 844 名学童进行了横断面研究。采集粪便样本，采用福尔马林-乙醚浓缩技术（FECT）、自然管沉淀技术（STST）、贝曼氏集卵法（BCT）、琼脂平板培养（APC）和实时聚合酶链反应（RT-PCR）进行处理。根据综合参考，计算每种诊断方法的敏感性、特异性、阳性预测值和阴性预测值。在 95%置信区间内，用 Kappa 值评估诊断方法的一致性。
结果
五种诊断方法对粪类圆线虫的综合检出率为 39.0%（329/844）。FECT、STST、BCT、APC 和 RT-PCR 从粪便样本中检测到寄生虫的检出率分别为 2.0%（17/844）、4.0%（34/844）、10.2%（86/844）、10.9%（92/844）和 28.8%（243/844）。BCT、APC 和 RT-PCR 联合检测粪类圆线虫的检出率最高（37.8%；319/844），其次是 STST、BCT、APC 和 RT-PCR 联合检测（37.3%；315/844）。FECT、STST、BCT、APC 和 RT-PCR 对综合参考的敏感性分别为 5.2%、10.3%、26.4%、28.0%和 73.9%。RT-PCR、APC、BCT、STST 和 FECT 与综合参考在检测粪类圆线虫方面的诊断一致性为中等（0.775）、轻度（0.321）、轻度（0.305）、轻度（0.123）和轻度（0.062）。
结论
RT-PCR 检测到的粪类圆线虫感染数量最多。与其他组合或单一诊断方法相比，RT-PCR 与 APC 和/或 BCT 的联合应用能更好地从粪便样本中检测到粪类圆线虫。因此，应提倡使用 RT-PCR 和 RT-PCR 与 APC 和/或 BCT 的联合诊断方法来检测粪类圆线虫感染。
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