A Novel Reporter System for the Isolation of Legionella Pneumophila Virulence Genes

Abstract

It bas been more than three decades since the now infamous events of the July 1976 American Legion convention in Philadelphia. On the centennial of Koch's groundbreaking discovery that bacteria caused anthrax, a mysterious outbreak of pneumonia ravaged the gathered Legionnaires (20). An estimated 182 cases of pneumonia occurred, with 147 patients requiring hospitalization and 29 fatalities. The media attention toward this mysterious disease was impressive, with reports leading the nightly news on all three major networks for over a week (12). Investigating epidemiologists proposed that the source of the outbreak was to be found at the hotel where many of the delegates stayed (20). The etiologic agent of the so-called Legionnaires’ disease was later found to be a previously unrecognized gram-negative bacterium (35) designated Legionella pneumophila (6). Numerous additional species have been identified and classified along with L. pneumophila in the newly created genus Legionella. Some of these have been reported to be pathogenic for humans as well (13).