- Tuberculosis (TB)
a serious infectious bacterial disease affects the lungs
- TB diagnosis
takes a few days which is time consuming
- New fast test
developed by scientists requires a very short time for the results to be
A simple and fast test
to diagnose tuberculosis will aid in better diagnosis of a feared lung
infection prevalent in developing countries. Tuberculosis
is a dreaded disease that is more
common in the developing nations than in the developed nations. This disease is
caused by the bacterium Mycobacterium
and is found to be highly infective in children, senior adults
and immune-compromised individuals.
The New and Simple
Test for Early Diagnosis of Tuberculosis
The new Tuberculosis test involves
mixing the sputum sample with the Fluorescent Dye like Solvatochromic and then leaving it aside for one hour. After which the sample is viewed
under the microscope for the presence of
of the New Method
- This is a simple
test that is easy to carry out and requires a very short time for the
results to be inferred.
- It does not
require expensive equipment or electricity, which are not always available
in certain parts of developing countries.
- Only live
bacteria are detected using this method. This is a big advantage over the
Ziehl Neelsen test that detects both live and dead bacteria. The ZN test,
therefore, cannot be used to detect the effectiveness of treatment
procedures. As Dr. Bertozzi adds
"if the drugs aren't working, you want to switch the patient to the next
treatment as quickly as possible so you don't contribute to drug
This simple and quick test for detecting
tuberculosis holds a lot of promises and if it is found to be viable for mass
detection, it would improve diagnosis and care of TB patients.
‘A simple and fast diagnosis will improve care for Tuberculosis (TB).’
a Fluorescent Dye
Some other researchers,
who were studying the bacterium and its ability to pick up the trehalose sugar
and integrate into its glycoprotein, tagged the sugar molecule with fluorescent
dye. Though this technique promised to aid in better detection of the bacterium
in the saliva, it had its drawbacks. The florescent dye got attached to certain
components of saliva, making detection of the bacterium difficult.
Bertozzi and colleagues
attached the trehalose to solvatochromic dye that began to glow only when the
sugar molecule was integrated into the glycoprotein of the bacterium.
About TuberculosisDuring the primary
infection of this bacterium, the immune system of the host attacks the bacteria
and prevents them from growing. This is called latent TB,
are no symptoms and the person cannot spread the infection. However, the
bacteria continue to live inside the host body in the form of a spore.
When the immune system
of the host is compromised due to another infection or disease, the TB
bacterium begins to grow and will give rise to a full-fledged TB infection.
Symptoms of TB include
- Chest pain
- Weight loss
- Loss of appetite
- Night sweats
- Blood with
The disease is found to spread through
droplet infection, where the bacterium is present in the sputum. When the
individual coughs, small amount of sputum is dispersed into the air and people
breathing in will inadvertently take in the bacterium. This leads to the spread
People who look after
patients with tuberculosis are at risk of getting the disease themselves. Young
children and elderly are also at risk of being infected. Other people who are
at high risk of getting the disease include people who work in prisons,
shelters for the homeless and health workers who are in close contact with
people who may suffer from the disease.
The droplets of the
sputum are spread when the infected individual coughs
, sneezes, sings or even speaks.
- It has been estimated that
nearly one-third of people in the world are infected with tuberculosis.
- According to 2014 statistics, there were
9.4 million people in the world who were infected with tuberculosis.
- TB is highly infectious when the individual
is attacked by another disease that lowers the immune system.
- TB is the leading cause of death among individuals who are infected
- Internationally when people who have both
HIV and TB die, they are categorized as having died
due to HIV infection.
- In 2014, there were one million cases of
TB amongst children.
Eliminating this disease
is a primary concern for healthcare providers across the world due to a large
number of deaths due to the disease. TB is fatal if it is not treated properly.
Current Problems in Diagnosis
- The major
hindrance to eliminating TB is the long drawn process of diagnosis.
Currently TB diagnosis takes a few days which is time consuming and
requires additional resources.
- In developing
countries, where TB is common, people need to travel to cities from
villages to avail treatment. When the diagnosis takes a few days for the
results to come in, people refuse to stay in the cities to receive the
results. They are forced to go back to their village even before the
results are ready as they need to spend on living expenses for a couple of
additional days spent in the city. This leads to a continued spread of the
- Hospitals are
short staffed and cannot afford to send a message to the village regarding
their disease status. This leads to an inability to begin treatment.
- In developed
countries, doctors rely on chest x-rays for better diagnosis. The sputum of the patients is then sent for
reaction (PCR) and analysis. These methods give an accurate
result within a short period of time. However, in developing countries,
the use of X-rays and PCR are limited by lack of access to continuous
electricity and poor affordability.
The need for a better
diagnostic test for TB has led chemists to develop a new test that is being
trialed in AfrNeelsen ica, where
the number of cases of TB is high.
Ziehl Neelsen (ZN)
The Ziehl Neelsen test
involves fixing the saliva sample on a glass slide and then staining it several
times to detect the presence of the organism. The entire process is time
consuming and it fails to detect Mycobacterium sometimes or gives rise to false
The lead researcher of
the study Dr. Carolyn R. Bertozzi who set out to find a better diagnostic test
for TB says "The ZN test is not very sensitive. It misses some cases of TB, and
it gives a lot of false positives."
The researchers of the
study have been studying the bacterium for 16 years.
of the Bacterium
The scientists studied
the glycolipids that were present in the walls of the bacterium. They found
that each glycolipid consisted of a sugar trehalose that was attached to either
a fat or a lipid.
When carefully modified
trehalose were provided to the bacterium, the sugar molecules were metabolized
and were integrated into glycoprotein.
- Tuberculosis (TB) Disease: Symptoms & Risk Factors - (http://www.cdc.gov/features/tbsymptoms/)
- Tuberculosis - (https://medlineplus.gov/tuberculosis.html)
- Data and Statistics - (http://www.cdc.gov/tb/statistics/)
- TB Statistics - Global, regional & high
burden - (http://www.tbfacts.org/tb-statistics/)