Stool Xpert^® MTB/RIF test for the diagnosis of childhood pulmonary tuberculosis at primary clinics in Zimbabwe

Abstract

SUMMARYOBJECTIVE: To evaluate the diagnostic performance of Xpert® MTB/RIF on stool samples from children with clinical suspicion of pulmonary tuberculosis (PTB) at primary care clinics.DESIGN: A cross-sectional diagnostic evaluation enrolling 5–16 year olds from whom one induced sputum (IS) sample was tested for microbiological TB confirmation. Results of a single stool sample tested using Xpert were compared against microbiologically confirmed TB, defined as a positive result on sputum microscopy and/or culture and/or IS Xpert.RESULTS: Of 222 children enrolled, 218 had complete microbiological results. The median age was 10.6 years (interquartile range 8–13). TB was microbiologically confirmed in 19/218 (8.7%) children. Of these, respectively 5 (26%), 9 (47%) and 15 (79%) were smear-, culture- and IS Xpert-positive. Stool Xpert was positive in 13/19 (68%) microbiologically confirmed cases and 4/199 (2%) microbiologically negative cases. Stool Xpert detected 76.9% (10/13) of human immunodeficiency virus (HIV) infected and 50% (3/6) of non-HIV-infected children with microbiologically confirmed TB (P = 0.241).CONCLUSION: Stool Xpert is a potential alternative screening test for children with suspected TB if sputum is unavailable. Strategies to optimise the diagnostic yield of stool Xpert assay need further study.

Molecular Detection of Mycobacterium tuberculosis from Stools in Young Children by Use of a Novel Centrifugation-Free Processing Method

“…This is the first large study, since initial proof-of-concept ( 10 ), to evaluate the performance of a novel centrifugation-free processing method for stool specimens, to assess its use with the Xpert MTB/RIF assay on stool to diagnose TB in children. Compared to microbiological confirmation using respiratory specimens, this method demonstrated diagnostic accuracy similar to those of recently published studies in young children ( 7 , 8 , 15 ), while studies enrolling mainly older children reported higher sensitivities for stool Xpert ( 9 , 16 , 17 ). This is most likely due to the lower bacillary concentrations present in respiratory specimens and, hence, in stools of young children, who seldom present with adult-type (cavitating) TB ( 18 , 19 ).…”

Evaluation of Xpert MTB/RIF testing for rapid diagnosis of childhood pulmonary tuberculosis in children by Xpert MTB/RIF testing of stool samples in a low resource setting

“…We observed the sensitivity of stool Xpert to be 88.9% as compared with GA culture, 100% with GA Xpert and 81.8% with GA Xpert. The stool Xpert sensitivity we observed was higher than that shown by Nicol et al in non-HIV children [ 6 ] and by Chipinduro et al in HIV and non-HIV children [ 13 ] possibly, due to the screening tool (modified KJ score) we used to recruit children with high likelihood of TB. However, the sensitivity of Xpert stool we observed was similar to that reported by Banada et al [ 14 ] who tested larger quantities of replicate stool samples from children with pediatric TB.…”

<p>Prevalence, Associated Risk Factors and Rifampicin Resistance Pattern of Pulmonary Tuberculosis Among Children at Debre Markos Referral Hospital, Northwest, Ethiopia</p>

“…In this study, the prevalence of pulmonary tuberculosis among children is 5.73% (22/384), which is similar to the finding in Tanzania (5.2%). 34 However, it is higher than the findings reported in Zambia (1.58%), 35 Mozambique (1.65), 36 South Africa (1.3%), 37 and lower than reports from India (15%), 38 Zimbabwe (8.7%), 39 Greenland (8.5%), 40 South Africa (13%), 41 Uganda (10%), 42 Ethiopia (13.6%), 43 Bangladesh (32.97%) 44 and Nigeria (32%). 45 The reason for variation might be due to the difference in the prevalence of tuberculosis in the general population, methods of sputum sample collection and diagnosis.…”