Photo Courtesy of http://en.rylkov-fond.org
by Kristina Chiu
Drug-resistant tuberculosis (TB) has been sweeping across international borders and is a critical
global health concern in the world community.
In Los Angeles alone, six patients were diagnosed with drug-resistant TB in 2010.
Although drug resistant TB is not as prevalent in the U.S. as it is in other countries, steps can be
taken to make sure it doesn’t become an issue in the future.
Drug-resistant TB is caused by mutant strains of mycobacteria, which also cause regular TB. In
many cases, drug-resistant TB can prove deadly because, as its name indicates, drug-resistant
TB cannot be treated with the usual antibiotics.
Drug-resistant TB is divided into two categories: multidrug-resistant TB (MDR-TB) and
extensively drug resistant TB (XDR-TB). MDR-TB is resistant to two of the most effective anti-TB
drugs, isoniazid and rifampicin. As first-line drugs, these are used to treat all patients with TB.
XDR-TB is resistant to both isoniazid and rifampicin along with at least one of three second-
line drugs, which are less effective against TB than first-line drugs. Thus, patients infected with
XDR-TB don’t have many treatment options available to them, and the options that they do
have aren’t very effective and have other side effects.
The World Health Organization (WHO) estimates that, in 2010, there were 650,000 cases
of MDR-TB world-wide. Approximately fifty percent of these cases are said to be in India
and China, which are ranked first and second on WHO’s list of countries with a high MDR-TB
burden. A high burden country is one that has more than 4000 new drug resistant TB cases
each year or one in which ten percent of all new TB cases are drug resistant.
MDR-TB has become a problem in high burden countries, many of which are developing
nations, due to a lack of available funding.
“There is often a lack of laboratory support to help diagnose drug resistant TB in high MDR-TB
burden countries,” said Dr. Brenda Jones, Associate Professor of Medicine at the Keck School
of Medicine. “Also, a lack of resources to pay for TB medications might prevent the use of the
appropriate drugs and adherence to treatment regimens.”
Treatment for regular TB requires patients to take anti-TB drugs for six months. However,
MDR-TB and XDR-TB require treatment for a time period of at least two years. Additionally, the
second-line drugs necessary to treat certain forms of drug resistant TB are more expensive than
the medication needed to treat non-drug-resistant forms of TB.
Patients must also take the prescribed TB medications for a complete two years, even if they
recover within that time period. Otherwise, the disease may come back even deadlier and more
drug resistant than before.
The U.S. Center for Disease Control and Prevention (CDC) states that the most important thing
a person can do to prevent the spread of MDR-TB is to take all of his/her medications exactly as
prescribed by his/her health care provider. Doses should not be missed and treatment should
not be stopped early.
“It is important to provide resources for TB control and public health,” said Jones. “We also
need to increase TB awareness and education in healthcare workers and patients.”