Programme on Emerging Infections, Infectious Diseases Division, icddr,b, Dhaka, Bangladesh.
Department of Paediatrics, Shaheed Suhrawardy Medical College and Hospital, Dhaka, Bangladesh.
Clin Infect Dis. 2021 Jul 15;73(2):226-234. doi: 10.1093/cid/ciaa583.
The World Health Organization recommends the Xpert MTB/RIF Ultra assay for diagnosing pulmonary tuberculosis (PTB) in children. Though stool is a potential alternative to respiratory specimens among children, the diagnostic performance of Xpert Ultra on stool is unknown. Thus, we assessed the diagnostic performance of Xpert Ultra on stool to diagnose PTB in children.
We conducted a cross-sectional study among consecutively recruited children (< 15 years of age) with presumptive PTB admitted in 4 tertiary care hospitals in Dhaka, Bangladesh, between January 2018 and April 2019. Single induced sputum and stool specimens were subjected to culture, Xpert, and Xpert Ultra. We considered children as bacteriologically confirmed on induced sputum if any test performed on induced sputum was positive for Mycobacterium tuberculosis and bacteriologically confirmed if M. tuberculosis was detected on either induced sputum or stool.
Of 447 children, 29 (6.5%) were bacteriologically confirmed on induced sputum and 72 (16.1%) were bacteriologically confirmed. With "bacteriologically confirmed on induced sputum" as a reference, the sensitivity and specificity of Xpert Ultra on stool were 58.6% and 88.1%, respectively. Xpert on stool had sensitivity and specificity of 37.9% and 100.0%, respectively. Among bacteriologically confirmed children, Xpert Ultra on stool was positive in 60 (83.3%), of whom 48 (80.0%) had "trace call."
In children, Xpert Ultra on stool has better sensitivity but lesser specificity than Xpert. A high proportion of Xpert Ultra assays positive on stool had trace call. Future longitudinal studies on clinical evolution are required to provide insight on the management of children with trace call.
世界卫生组织建议使用 Xpert MTB/RIF Ultra 检测法诊断儿童肺结核（PTB）。虽然粪便可能是儿童呼吸道标本的替代物，但 Xpert Ultra 检测粪便的诊断性能尚不清楚。因此，我们评估了 Xpert Ultra 检测粪便诊断儿童 PTB 的诊断性能。
我们在 2018 年 1 月至 2019 年 4 月期间在孟加拉国达卡的 4 家三级保健医院连续招募疑似患有 PTB 的儿童（<15 岁）进行了一项横断面研究。采集单个诱导痰和粪便标本进行培养、Xpert 和 Xpert Ultra 检测。如果诱导痰的任何检测均对结核分枝杆菌呈阳性，则认为诱导痰检测阳性的儿童为细菌学确诊；如果在诱导痰或粪便中检测到结核分枝杆菌，则认为该儿童为细菌学确诊。
在 447 名儿童中，29 名（6.5%）在诱导痰中细菌学确诊，72 名（16.1%）在诱导痰中细菌学确诊。以“在诱导痰中细菌学确诊”为参考，Xpert Ultra 检测粪便的敏感性和特异性分别为 58.6%和 88.1%。Xpert 检测粪便的敏感性和特异性分别为 37.9%和 100.0%。在细菌学确诊的儿童中，60 名（83.3%）Xpert Ultra 检测粪便为阳性，其中 48 名（80.0%）为“微量信号”。
在儿童中，Xpert Ultra 检测粪便的敏感性优于 Xpert，但特异性较低。大量 Xpert Ultra 检测粪便阳性的检测结果为微量信号。需要进一步开展前瞻性纵向研究，以提供关于处理微量信号儿童的临床进展方面的见解。
