Xpert MTB/RIF on Stool Is Useful for the Rapid Diagnosis of Tuberculosis in Young Children With Severe Pulmonary Disease

Abstract

Background Tuberculosis (TB) continues to result in high morbidity and mortality in children from resource-limited settings. Diagnostic challenges, including resource-intense sputum collection methods and insensitive diagnostic tests, contribute to diagnostic delay and poor outcomes in children. We evaluated the diagnostic utility of stool Xpert MTB/RIF (Xpert) compared with bacteriologic confirmation (combination of Xpert and culture of respiratory samples). Methods In a hospital-based study in Cape Town, South Africa, we enrolled children younger than 13 years of age with suspected pulmonary TB from April 2012- August 2015. Standard clinical investigations included tuberculin skin test, chest radiograph and HIV testing. Respiratory samples for smear microscopy, Xpert and liquid culture included gastric aspirates, induced sputum, nasopharyngeal aspirates and expectorated sputum. One stool sample per child was collected and tested using Xpert. Results Of 379 children enrolled (median age, 15.9 months, 13.7% HIV-infected), 73 (19.3%) had bacteriologically confirmed TB. The sensitivity and specificity of stool Xpert vs. overall bacteriologic confirmation were 31.9% (95% CI 21.84-44.50%) and 99.7% (95% CI 98.2-100%) respectively. 23/51 (45.1%) children with bacteriologically confirmed TB with severe disease were stool Xpert positive. Cavities on chest radiograph were associated with Xpert stool positivity regardless of age and other relevant factors (OR 7.05; 95% CI 2.16-22.98; p=0.001). Conclusions Stool Xpert can rapidly confirm TB in children who present with radiologic findings suggestive of severe TB. In resource-limited settings where children frequently present with advanced disease, Xpert on stool samples could improve access to rapid diagnostic confirmation and appropriate treatment.

Diagnostic performance of non-invasive, stool-based molecular assays in patients with paucibacillary tuberculosis

“…Culture identification also has limited role in routine diagnosis in India and is recommended for screening of drug-resistance 5,6 . Many recent studies have tested efficacy of stool in molecular diagnosis of pediatric PTB, while scarce reports are available on adult stool testing for detection of PTB from other countries [7][8][9][10][11][12][13][14][15][16] .…”

Alternative sputum collection methods for diagnosis of childhood intrathoracic tuberculosis: a systematic literature review

“…Out of 440 records screened, 30 studies (31 articles)5–35 were included in the review (online Supplementary figure 1).…”

Urine Xpert MTB/RIF for the diagnosis of childhood tuberculosis

“…Other non-respiratory specimens have been tested using Xpert MTB/RIF in children. Previous studies have shown that stool Xpert has similar performance as gastric aspirate in HIVinfected children (LaCourse et al, 2018) and in those with severe pulmonary disease (Walters et al, 2017), however, processing of stool samples is tedious and may not be readily done in peripheral laboratories.…”