Tuberculosis (TB) is one of the major public-health challenges in the world today, with an estimated 1.5 million deaths in 2013. More alarmingly, the incidence of multi-drug resistant (MDR) TB is rapidly increasing, especially in low resource environments. The goal of this project is to develop an inexpensive portable system and method using which it will be possible to both detect the presence of low loads of Mycobacterium tuberculosis (Mtb) in sputum samples AND perform Drug Susceptibility Testing (DST) for 12 drug formulations: all within 3 days of sample collection. The proposed approach involves (a) collecting all the ~1000 Mtb cells present in 2-10 ml of sputum sample into a small (200 ul) of buffer (growth medium) during the standard decontamination process using a set of super-paramagnetic nanoparticles (MNPs) functionalized on the surface with amino-polysaccharide moieties that bind to bacterial cells (b) dispensing the 200ul suspension into 16 micro-wells, each containing different formulations of freeze-dried growth media and/or drugs of interest (c)monitor cells in each well using micro-channel Electrical Impedance Spectroscopy (m-EIS). m-EIS reveals in real time if cells are growing, dying, or rendered static in the presence of antibiotic. The first 2 steps (pre-concentration using MNPs and loading into microfluidic channel) will take less than 1 hour, and the monitoring of death/growth/stasis will take 3 days. In Phase I, we will demonstrate proof-of-concept for the above approach by (1) verifying the efficacy of our sample preparation / pre-concentration technique involving MNPs, (2) establishing the ability of the m-EIS method to record in real time, the death, proliferation, or statis of mycobacteria in the presence of candidate drug formulations, and (3) designing a prototype cassette containing 16 wells, and fabricating the same using 3D printing (stereolithography). In addition, we will (4) propose a detailed design (electrical, mechanical and fluidic) of the automated system (disposables and non- disposable hardware) that we will build in Phase II. Being able to detect the presence of low loads of mycobacteria and gaining knowledge about the drug resistance profile of a particular isolate in 3 days will be a ?game changer? in our efforts to combat the spread of TB (esp. MDR TB). It will lead to better outcomes for patients (less mortality, quicker recovery), and also better public health (less transmission to others and less fostering of drug resistance in populations).
The World Health Organization has highlighted the emergence of Multi Drug Resistant (MDR) TB as a major global health challenge, and stressed the need to ?expand rapid testing and detection of drug-resistant TB cases?. The proposed instrument will cut the time needed to perform susceptibility tests against multiple drugs to 3 days (vs. > 4 weeks needed using current technology).
