Xpert® MTB/RIF assay testing on stool for the diagnosis of paediatric pulmonary TB in Tanzania

Abstract

SETTING: Six health facilities in Dar es Salaam, Tanzania.OBJECTIVE: To evaluate the use of stool specimens in the diagnostic workup of paediatric TB using the Xpert® MTB/RIF assay.DESIGN: Between December 2018 and May 2019, we performed a cross-sectional diagnostic study of children aged between 1 month and 14 years with presumptive TB. A single stool specimen was tested using Xpert. The result was compared with the reference microbiological standard for respiratory or gastric specimens tested using Xpert and/or solid culture. The sensitivity, specificity and predictive values of stool Xpert assay were assessed.RESULTS: A total of 225 children with a median age of 2.17 years (IQR 1.16–5.19) were enrolled; 165/225 (73.3%) were aged <5 years. Of 225 children, 8 (3.6%) were diagnosed with TB as they were culture- or Xpert-positive on sputum/gastric aspirate. The stool Xpert assay showed a sensitivity of 62.5% (95% CI 25–92) and specificity of 100% (95% CI 98–100) against the reference standard.CONCLUSION: Use of the Xpert assay on stool specimens had a moderate sensitivity and high specificity in the diagnosis of pulmonary TB in children. Our data adds to the body of evidence for the use of Xpert assay on stool as a non-respiratory specimen to complement conventional methods used to diagnose the disease.

Genomic insights into anthropozoonotic tuberculosis in captive sun bears (Helarctos malayanus) and an Asiatic black bear (Ursus thibetanus) in Cambodia

“…1 and 2 . Sample sites are broadly categorised as pulmonary or extra-pulmonary, with positive cultures from gastric fluid or faeces, in the absence of any macroscopic evidence of extra-pulmonary disease, considered to be of pulmonary origin 45 , 46 . M. tuberculosis was cultured from extra-pulmonary sites in 7/10 (70%) Lineage 2 cases, including three cases with no evidence of pulmonary disease, whereas in Lineage 1 M .…”