Researchers have decoded the genome of Legionella pneumophila, the bacteria responsible for Legionnaires' disease

Researchers at Columbia University Medical Center have decoded the genome of Legionella pneumophila, the bacteria responsible for Legionnaires' disease, and have found a few surprises in the bug's 3,000 genes.

Legionnaires' disease was first identified in Philadelphia in 1976, after 220 attendees at an American Legion convention were stricken with pneumonia and 34 died. It was soon determined that they were infected with a previously unknown bacteria, L. pneumophila, that had saturated the hotel's air conditioning system. Subsequently, L. pneumophila and related species of Legionella were found in standing water worldwide and are also frequent causes of hospital-acquired pneumonias.

In the new report, published in the Sept. 24 issue of Science, a group of researchers led by James J. Russo, Ph.D., associate head of sequencing and chemical biology at the Columbia Genome Center, Howard Shuman, Ph.D., Professor of Microbiology, and Jingyue Ju, Ph.D., associate professor of Chemical Engineering and colleagues found several unusual aspects of the bacteria's genome that may lead to new therapies. The genome contains a remarkable number of proteins that pump toxins out of the bacteria, which may account for its survival within plumbing systems, even after treatment with potent biocides. And it possesses a very large number of candidate virulence factors, proteins that may account for its ability to infect and kill human cells.