EVERY second, according to the World Health Organization, someone becomes infected with the bacteria that cause tuberculosis. In the October issue of the journal PLoS Genetics, researchers from the Genome Institute of Singapore identified a gene that might play a role in making people more susceptible to pulmonary tuberculosis.

A third of the population worldwide is infected, though the WHO says only 5 to 10 percent of those infected develop the disease. Approximately eight million tuberculosis cases develop annually, and two million people die each year.

Though there is a vaccine for tuberculosis and drugs to treat the disease, some of the bacterial strains have proved to be resistant against the medications. These drug-resistant strains have been found in every country.

Proposal

Most people are inoculated with the tuberculosis vaccine, more commonly known as the BCG shot, in childhood. Given the prevalence of the disease though, some researchers have proposed that the current vaccine may only protect those inoculated against specific bacterial strains.

In the November issue of the journal Infection and Immunity, researchers from the American Food and Drug Administration’s Center for Biologics Evaluation and Research countered the notion by showing the current tuberculosis vaccine doesn’t offer strain-specific immunity.

The vaccine was tested on mice exposed to nine different TB strains and induced protective immunity against all of them. The data, wrote the researchers, “suggest that strain-specific resistance to BCG-induced protective immunity may be uncommon.”

Researchers are developing even more drugs to combat tuberculosis, some of which are already being tested on humans in clinical trials. While studying some of these newer drugs, researchers from the American National Institute of Allergy and Infectious Diseases, a division of the National Institutes of Health, and the Novartis Institute for Tropical Diseases in Singapore figured out exactly how these potential medications actually combat drug-resistant tuberculosis.

The information could help scientists develop more directed drug treatments to cure the latent tuberculosis in 90 percent of those infected, and develop similar treatments against other disease-causing bacteria as well.

The report appeared in the Nov. 28 issue of the journal Science. The work was led by NIAID researcher Clifton Barry III.

No drug available

“Currently, there are no drugs available that specifically target latent tuberculosis infections in which bacteria are present but are not actively dividing,” NIAID Director Anthony Fauci said in a statement.

“Their discovery is a promising step toward developing effective drugs against latent TB as well as other bacteria.”

Barry and his colleagues aren’t the first to find a way to treat the latent tuberculosis infections, though their findings are arguably the most recent. In October researchers at Missouri’s St. Louis University School of Medicine revealed that a drug currently in clinical trials for use against multidrug resistant strains had proved effective at killing latent bacteria. Their work appeared in the Journal of Infectious Diseases.

E-mail the author at massie@ massie.com.