Progress in the Battle Against Nosocomial Legionnaires' Disease: Shedding Light on Shades of Gray

Abstract

EXCERPT Remember how much you don’t know.—William Osler, circa 1900 Remember how much you know, but haven’t applied.— Osler’s ghost, 2003 In 1977, Fraser et al. described an outbreak of pneumonia among legionnaires attending a convention at a hotel in Philadelphia in 1976.1 The outbreak, which later became known as legionnaires’ disease, was caused by a new pleomorphic, faintly staining gram‐negative bacillus, Legionella pneumophila, that was isolated at the Center for Disease Control from lung tissues of legionnaires who died.2 Legionella are a fascinating group of intracellular pathogens that often inhabit aquatic environments, where they can survive and even multiply in protozoa.3 There are 42 species of Legionella and several different serotypes, but L. pneumophila serotype 1 is responsible for most lower respiratory tract infections.3,4 Hematogenous or lymphatic spread from the lungs to the liver, spleen, lymph nodes, myocardium, and kidneys may occur.3