Drug-Resistant TB

In July 2007, Atlanta lawyer Andrew Speaker set off an international panic when he boarded a transcontinental flight from France to the U.S., despite his knowledge that he had been infected with an extremely drug-resistant form of TB.

The media explosion about the case was rare for a developed country like the U.S. where rates of TB are relatively low and active infections are usually treated with antibiotics.

In the days before antibiotic treatment, TB was known as "consumption" because its victims would slowly waste away as the disease consumed them from the inside—tuberculosis is a bacterial infection that most commonly attacks the lungs, though it can also attack the spine, lymph nodes, bladder, or skin.

Today, the disease only seems to be a minor threat; since 1992 TB has been on the decline in the U.S., and, thanks to antibiotics, death rates are at an all-time low. In 2005, only 646 people died of TB, roughly 0.2 percent of the 14,000 people diagnosed with active TB that year.

There is, however, cause for concern: The bacteria that causes TB has increasingly resistant to many antibiotics currently available in the medical arsenal.

A worrisome trend

In March 2008, the World Health Organization reported that although global rates of TB are down, rates of drug-resistant TB are up. The WHO estimates that in 2006 there were at least 500,000 cases of multiple-drug-resistant TB worldwide.

Domestically, multiple-drug-resistant TB is still rare. In 2006, only 1.1 percent of TB cases were resistant to both of the main drugs used to treat TB, while there are some secondary drugs that can be used instead.

The emergence of drug-resistant strains has many health officials worried that TB could eventually make a comeback—and could develop an immunity to all of today's effective treatment drugs.

Where does drug resistance come from?

Initially, antibiotic-resistant strains of TB can evolve when someone fails to take their medication as prescribed.

Because antibiotic treatment for TB is long (at least six months to one year), expensive, and involves taking medication with some unpleasant side effects, some people discontinue using the medication once they feel better but before the treatment has fully run its course. Other times, people take the medication erratically because of simple forgetfulness.

In addition, not everyone in the world has access to the same diagnostic tools that we have here in the U.S. Some countries lack the infrastructure to accurately test an infected individual for drug-resistant TB before prescribing medication.

"If someone with drug-resistant TB is prescribed a drug regimen that the bacteria is already somewhat resistant to, you run the risk of amplifying whatever drug resistance there is," explains Philip LoBue, M.D., for the Centers for Disease Control and Prevention.