New Diagnostic Test for Tuberculosis
More than a century ago, Koch discovered
Mycobacterium tuberculosis and Ziehl and Neelsen developed a way to
stain it. Then science gave a big yawn and turned over to more exciting
things; and we limped along with microscopy as the only definitive tool
for diagnosis of tuberculosis.
Finally someone got up. With funding from The Bill and
Melinda Gates Foundation, FIND (Foundation for Innovative and New
Diagnostics) developed a new test called Xpert MTB/RIF, a hemi-nested PCR,
to confirm the diagnosis of Mycobacterium tuberculosis. It
simultaneously also targets the rpoB gene, which is critical for
identifying mutations associated with rifampicin resistance that occurs
with a frequency of 95% in MDR-TB. Hence identifying rifampicin resistance
initially should prompt an immediate detailed sensitivity testing against
second line agents.
Tests results are available in just 2 hours. Acceptable
samples include unprocessed sputum or sediment from concentrated
specimens. Cepheid (the company which is marketing it) is offering a 75%
discount for poorer nations, meaning the tests will cost $16.86 and the
machine will cost around $17,000.
A trial on 1730 patients from Peru, Azerbaijan, South
Africa, and India using the technique was recently published in the NEJM.
It had a sensitivity of 98.2% in smear positive patients and 72.5% in
smear negative patients. Specificity was 99.2% and 97.6% of rifampicin
resistant bacteria were correctly identified (NEJM September 9, 2010).
The Road Ahead – Reforms in Medical Education
In 1912, the Flexnor Report sparked ground breaking
reforms in medical education. Now, a Commission consisting of 20
professionals from diverse countries round the world has published its
report on how to relook at the direction in which we must mould our
medical education. Internationally, 2420 medical schools train roughly 1
million doctors, nurses and health professionals. Education in the last
century has evolved from a science based curriculum to a problem based one
and is now entering the third phase of systems based education. The need
of the hour is to improve the performance of health systems by adapting
core professional competencies to specific contexts, while drawing on
global knowledge. We need to change the style of learning from mere
information collectors to development of leaders who can induce change in
their microenvironment.
Great emphasis has been placed on interdependence and
change from stand-alone institutions to networks, alliances, and consortia
and harnessing of global flows of educational content, teaching resources,
and innovations. Deep thought about how we train future doctors will
decide the health of the nation The Lancet, 4 December, 2010).
Gouri Rao Passi,
Email:
[email protected]