Nontuberculous ( Environmental ) Mycobacterial Disease 12

12 Nontuberculous mycobacteria (NTM) are in the same family as the organisms that cause tuberculosis and leprosy, but unlike those organisms, NTM are widely dispersed in our environment, vary greatly in their ability to cause disease, and are not spread from person to person. There are about 140 different species of mycobacteria. Mycobacteria not closely related to tuberculosis or leprosy are called nontuberculous mycobacteria, environmental mycobacteria, and myco-bacteria other than tuberculosis (MOTT). Recent studies have documented increases in NTM infections, and, in many areas of the United States, these infections outnumber tuberculosis. Epidemiology, prevalence, economic burden, vulnerable populations Nontuberculous mycobacteria were first identified in the late 19th century, when a tuberculosis-like disease was reported in chickens. In the 1930s, they were documented to cause disease in humans, but it was not until the 1950s that pulmonary disease due to these organisms became more commonly recognized. Most clini-cians discounted the clinical significance of these bacteria, until the acquired