Preliminary evaluation of mycobacterium tuberculosis detection in culture and artificial sputum using a bionanopore membrane and realtime PCR

Abstract

The rapid detection and diagnosis of Mycobacterium tuberculosis is critical to evaluate disease severity, efficacy of treatments and therapeutics, and public health monitoring. This study evaluated a BioNanoPore technology (BNP™ Middlebrook agar) to detect and quantitate M. tuberculosis in less time than traditional plate counting methods. BNP™ Middlebrook enabled visual detection of M. tuberculosis from actively-growing cultures and inoculated artificial sputum within 5 days; however, colonies were not visible on Middlebrook 7H10 agar. For cultures incubated in the presence or absence of artificial sputum for 19 days on BNP™ Middlebrook, M. tuberculosis ranged from 5.81-5.86 log10CFU/mL from liquid culture and 6.39-6.50 log10CFU/mL in artificial sputum; counts for M. tuberculosis in liquid culture ranged from 5.70-5.85 log10CFU/mL on Middlebrook 7H10. All colonies from 19 day-old cultures evaluated from the BNP™ Middlebrook and Middlebrook 7H10 media were positive for the Mycobacterium insertion sequence (IS) 6110 by real-time PCR. This study demonstrates that BNP™ Middlebrook can detect M. tuberculosis faster than standard plating techniques in the presence or absence of a simulated biological matrix (artificial sputum). Moreover, the BNP™ Middlebrook color development step does not interfere with real-time PCR detection of IS 6110. This study provides a preliminary assessment of the potential use of BNP™ Middlebrook for a more rapid screening and detection of viable M. tuberculosis with respect to clinical specimen evaluation, therapeutic treatment/vaccine efficacy, or epidemiological surveillance. © 2012 Rogers JV, et al.