saliva is another cause of worry which
takes a physical, emotional and mental
toll on the patient.
Since most infected individuals begin to
feel better after a few weeks of treatment
and the length and side-effects of the
drug treatment are arduous, many
patients stop the treatment prematurely
or skip doses. Rampant patient
non-compliance when it comes to
completion of anti-TB therapy is one of
the main factors for the emergence of
a more severe form of the disease, one
which is resistance to common drugs!
This is a big reason for TB reactivation
and the continued prevalence of this
disease even though it is completely
curable in most cases.
Drug resistance in TB has been
known since the first antibiotics to
treat this disease were put into place.
An increasingly larger repertoire of
drug resistant strains necessitated and
increasingly larger arsenal of drugs
to treat the disease. As of today, TB
strains resistant to one of the first
line of four antibiotics are called
resistant strains. Strains resistant to
two first line antibiotics are called
multi-drug resistant strains of TB or
MDR-TB. These are treated with a
second line of antibiotics, consisting
of fluoroquinolones (levofloxacin,
moxifloxacin and gatifloxacin) or
injectable drugs such as amikacin,
kanamycin and streptomycin. More
recently, a third category of strains
labelled Extensively drug resistant-
or XDR-TB has been described with
resistance to a fluoroquinolone and at
least one of three injectable drugs. A total
of 12 drugs are approved today, each of
which individually and in combination
are used to treat these three categories of
TB, MDR-TB and XDR-TB. However, a
little characterized fourth type of strain,
dubbed totally drug resistant- or TDR-
TB has been reported in India, Italy,
Iran and South Africa. These strains are
completely resistant to all known anti-
TB medication and given the airborne
and infectious nature of the disease, are
ticking time bombs of catastrophe.
NEWER STRATEGIES IN TB HEALTHCARE
The emergence of drug resistance, the
persistently high rate of TB incidence
52
Volume 4 | Issue 1 | January-March 2019
and TB mortality and the challenges
associated with patient non-compliance
demand improved methods to detect
TB with high accuracy, newer drugs to
treat resistant forms of TB and increased
awareness of the disease.
Bedaquiline and delamanid are two
new drugs for TB that have shown
promising results in clinical trials
after nearly 40 years of failed attempts.
These two drugs have received approval
for use in the treatment of MDR- and
XDR-TB. Additionally, a new drug
combination involving bedaquiline,
pretomanid and linezolid is reported
to have successfully treated XDR-TB
in six months with a lower mortality
rate than current treatments. However,
these new treatment regimens are yet
to enter mainstream clinical practice,
with further and larger clinical trials
needed to make an accurate cost-benefit
analysis of these strategies.
LOOKING TO THE FUTURE
Although the current situation of TB
in India and worldwide looks bleak,
the global TB incidence is falling at
the rate of 2% per year. According to
WHO, this rate needs to increase to
5% to achieve the WHO Global Plan
to End TB milestones of reaching
90% of all people with TB through
national TB programmes, reaching
atleast 90% of vulnerable high-
risk population through affordable
treatment and achieve atleast 90%
success in the treatment of all
people diagnosed with TB. Achieving
both WHO and RNTCP milestones
will require a concerted effort by
policymakers, healthcare providers,
TB researchers, patients and the
general public. What we need
today is increased public spending
on healthcare to make TB therapy
affordable and accessible, improvement
of research funding and infrastructure
and stronger public awareness
campaigns to disseminate the reality
and requirements of ending TB.
Over just the past two centuries, TB is
estimated to have killed 1 billion people,
which is more than the number of people
killed due to AIDS, cholera, influenza,
plague and smallpox combined! It
is time we take the initiative and
responsibility to help the millions that
are suffering from this deadly disease.
Vignesh Narayan is a scientist and
science writer at the Indian Institute
of Science who currently studies the
molecular biology of the TB pathogen
Mycobacterium tuberculosis in an
attempt to understand how the
bacterium senses and responds to
its environment and develop new
drugs and drug targets to combat the
disease.