Sputum-spotted solid matrix designed to release diagnostic-grade Mycobacterium tuberculosis DNA demonstrate optimal biocontainment property.

Biosafety quotient of a reagent-coated cellulose matrix designed to release Mycobacterium tuberculosis (Mtb) DNA from sputum deposited onto it, was determined. Thirty-seven sputum samples infected with Mtb and 5 sputum samples from healthy individuals were processed and spotted onto the TBSend cards. Live Mtb bacilli were attempted for rescue from the spotted TBSend cards by washing them in phosphate buffer under mild shaking conditions. No live Mtb bacilli could be detected by the BACTEC MGIT 960 TB System from both Mtb infected as well as non-infected, sample-spotted TBSend cards when they were washed at two different time-points, viz., 1 minute and 15 hours from the time of spotting of the cards with sputum mixed with the preprocessing "spotting" buffer. The study reiterated published finding that chaotropic agents, which is an active component of the TBSend card module, have cent per cent bactericidal properties with regard to Mtb.