Xpert MTB/RIF on Stool Is Useful for the Rapid Diagnosis of Tuberculosis in Young Children With Severe Pulmonary Disease.
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 to 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 versus overall bacteriologic confirmation were 31.9% [95% confidence interval (CI): 21.84%-44.50%] and 99.7% (95% CI: 98.2%-100%), respectively. A total of 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 [odds ratios (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.
From the *Desmond Tutu TB Centre, Department of Paediatrics and Child Health, †DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, MRC Centre for Tuberculosis Research, Division of Medical Physiology, Faculty of Medicine and Health Sciences, ‡Department of Medical Microbiology and National Health Laboratory Service, §DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, US/SAMRC Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, and ¶Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa.
Elisabetta
E
Walters
Marieke Magrieta
MM
van der Zalm
Megan
M
Palmer
Corné
C
Bosch
Anne-Marie
AM
Demers
Heather
H
Draper
Pierre
P
Goussard
Hendrik Simon
HS
Schaaf
Sven Olaf
SO
Friedrich
Andrew
A
Whitelaw
Robin
R
Warren
Robert P
RP
Gie
Anneke C
AC
Hesseling
D002648:Child; D002675:Child, Preschool; D005243:Feces / Q000382:microbiology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D058889:Molecular Typing; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013902:Radiography, Thoracic; D013997:Time Factors; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000000981:diagnostic imaging