Non-tuberculous mycobacterial pulmonary disease (NTM-PD)

JAKKO VAN INGEN: Hello, and welcome to this next edition in the Henry Stewart Talks series on respiratory infections. My name is Jakko van Ingen. I'm a resident in clinical microbiology at the Radbound University, Nihmegen Medical Center, which is a large university hospital in the east of the Netherlands, which hosts the National Reference Clinic for non-tuberculous mycobacterial disease and the National Reference Laboratory for laboratory diagnosis of non-tuberculous mycobacterial diseases. Today, I would like to share with you some of the recent data and my own thoughts on non-tuberculous mycobacterial pulmonary disease, focusing on its diagnosis and management.

Any talk about mycobacteria of course has to start by mentioning that in 1882, Robert Koch, a German microbiologist, found the causative agent of human tuberculosis, mycobacterium tuberculosis. And immediately after this finding, many researchers started to look for the source of tuberculosis in humans. Because at that time, it was not thought that this was an infectious disease that would spread human to human. So people actually went searching in a variety of animals in the environment. And then many of those investigations did turn up acid fast bacilli that turned out to be mycobacteria. And at the time because, by their microscopic appearance, they seemed to be a little different from mycobacterium tuberculosis. Many of them were dubbed atypical mycobacterium tuberculosis. And probably many of them were non-tuberculous mycobacteria, as they were found in a lot of animals that we now know harbor some non-tuberculous mycobacteria, like birds that are known to carry mycobacterium avium and mycobacterium genavense. Or reptiles that are known to harbor mycobacterium chelonae and the fish that are known to harbor mycobacterium marinum. And in the environmental samples, like basic water and soil samples, a variety of non-tuberculous mycobacteria were found at the time. It was only in the first five decades of the last century that sporadic case reports of disease caused by these atypical mycobacteria started to emerge. And at that time, many of those strains were given names, referring to either a patient or the localization of where the patient reported to his physician. So it's unclear what species they were. So in 1953, Buhler and Pollak for the first time recorded clear-cut lung disease caused by a non-tuberculous mycobacterium. In their tuberculosis sanatorium, they found that two patients had a clinical disease that resembled pulmonary tuberculosis. But during their life, they only excreted mycobacteria in their sputum sample that turned yellow if the cultures were exposed to a light source, which is something that mycobacterium tuberculosis do not do. And these patients did not respond to their tuberculosis treatment, and died. And during autopsy, samples from their lung lesions were taken and again yielded these yellow mycobacteria in culture that we now know are mycobacterium kansasii. And that was actually the first time that investigators realized that these non-tuberculous mycobacteria can cause a tuberculosis-like pulmonary disease. And then it took up to the 1980s to discover that there was another respiratory infection caused by non-tuberculous mycobacteria with a very different and very distinct radiological presentation. And that is the nodular bronchiectatic lung disease that I'll focus on some more later on, a disease that at the time was dubbed the Lady Windermere syndrome. And then also in the 1980s, the non-tuberculous mycobacteria in general got more attention, because mycobacterium avium was found to cause disseminated disease in HIV/AIDS patients with a very high mortality rate.