Title: Utility of Xpert MTB/RIF assay for diagnosis of childhood tuberculosis- Extrapulmonary and Pulmonary

Authors: Shilpa Arora, Neerja Jindal, Ramandeep Kaur, Dr Gurmeet Kaur Sethi, Dr Amarpreet Kaur

 DOI:  https://dx.doi.org/10.18535/jmscr/v6i5.57

Abstract

Background: Xpert MTB/RIF assay is now recommended by WHO for diagnosis of tuberculosis in children but evaluation data is limited.

Methods: The study was conducted on 186 consecutive specimens (both respiratory and non respiratory) collected between October 2013 to July 2016 from 171 children having MDR TB or/and clinically suspected tuberculosis. Of the 186 specimens, maximum were sputum 83 (44.6%) followed by gastric aspirate 46 (24.7%), CSF 34 (18.3%), tissue biopsies 8 (4.3%), pleural fluid 6 (3.2%), ascitic fluid 5 (2.6%) and lymph node aspirates 4 (2.2%).

Each specimen was subjected to smear examination (direct and after decontamination), culture on Lowenstein Jensen (LJ) medium and Xpert MTB/RIF assay.

Results: Analyses on per-sample basis showed that direct smear was positive in 54 (29.2%), culture in 78 (42.2%) and Xpert MTB/RIF assay in 77 (41.6%) specimens. Overall sensitivity and specificity of Xpert MTB/RIF was 93.6% and 96.2% while that of smear was 69.7% and 98.9% respectively against culture as the gold standard. Of the total 77 specimens positive by Xpert MTB/RIF, rifampicin resistance was observed in 7 (9.1%).

Conclusion: Xpert MTB/RIF assay is a promising tool for diagnosis as well as detection of rifampicin resistance because of its high sensitivity, specificity and rapidity. However, as more than 50% of clinically suspected children still remain unconfirmed, further refinement of the test before it can replace the current reference standards for diagnosis is to be looked into.

Keywords: Tuberculosis, Children, Xpert MTB/RIF, Multidrug resistant.

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Corresponding Author

Dr Shilpa Arora

Department of Microbiology, GGSMC & Hospital, Faridkot, India

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