The tuberculosis bacterium is an insidious germ that can lie dormant for many years, then suddenly emerge and cause potentially fatal disease.
Earlier this year, researchers in Sweden proposed a provocative explanation: TB bacteria have the ability to turn into dormant, armor-plated spores. If true, the findings would provide promising new avenues of research in the worldwide fight against TB.
But a new study by researchers at Loyola University Health System and other centers casts doubt on the TB spore theory. Researchers were unable to detect spores in TB cultures and demonstrated that the TB bacterium doesn't even contain genes related to those needed to produce spores. Researchers also failed to find any spores in frogs infected with TB bacteria, which would have been expected if TB bacteria produced spores in the course of infection.
Results are published in the Proceedings of the National Academy of Sciences (PNAS).
The new findings could save TB researchers from pursuing strategies that likely would prove to be fruitless, said Loyola microbiologist Adam Driks, Ph.D., second author of the new study. Driks is an associate professor in the Department of Microbiology and Immunology at Loyola University Chicago Stritch School of Medicine. The new study was directed by Richard Losick, Ph.D, and the first author is Bjorn Traag, Ph.D., both of Harvard University.
"Our study illustrates the essential contributions that basic science makes to translational and clinical research," Driks said. "It can help ensure that efforts to improve therapeutics and treatment are focused in the most productive directions."
Tuberculosis, caused by the bacterium Mycobacterium tuberculosis, is the leading cause of death worldwide by a single bacterial germ. The World Health Organization estimates there were 9.3 million new TB cases and 1.3 million TB deaths worldwide in 2007.