Stool as Appropriate Sample for the Diagnosis of Mycobacterium tuberculosis by Gene Xpert Test
Open Journal of Respiratory Diseases
Diagnosis of pediatric pulmonary tuberculosis (PTB) is a challenge. Symptoms are nonspecific. Young children are unable to expectorate sputum samples; the procedures for obtaining respiratory samples are invasive. Thus Mycobacterium tuberculosis cultures and smears often are not performed. Stool samples were used as an alternative to respiratory samples for the diagnosis of pediatric PTB using stool Xpert MTB/RIF and its sensitivity for detecting the DNA of MTB in stool was determined. Methods:
... The study was a laboratory-based cross-sectional prospective design. Stool specimen was collected from PTB suspected children (<15 years) attended in Gertrude's Children's Hospital Nairobi and Kiambu District Hospital from September 2013 to March 2014. Stool for Xpert was processed in two ways, direct and prior extraction of DNA using QIAGEN stool DNA extraction kit. Result: A total sample of 91 stool specimen was collected from patients. Of these 53 (58.2%) had sputum ZN smear microscopy. Six (11.3%) of them were confirmed smear positive for PTB. Stool Gene Xpert was positive in all the six smear positive children. Four (7.5%) smear negative patients tested positive by stool Gene Xpert test. This association is significant (P = 0.000). Conclusion: This study reports that Mycobacterium tuberculosis DNA can be detected in stool using Xpert testing with a higher sensitivity. Therefore stool which can easily be obtained is an appropriate alternative sample for the diagnosis of PTB using Xpert assay for children unable to give respiratory samples. Furthermore Xpert turn round time is less than 2 hours.