The complexities and challenges of preventing and treating nontuberculous mycobacterial diseases

Abstract

Seemingly innocuous nontuberculous mycobacteria (NTM) species, classified by their slow or rapid growth rates, can cause a wide range of illnesses, from skin ulceration to severe pulmonary and disseminated disease. Despite their worldwide prevalence and significant disease burden, NTM do not garner the same financial or research focus as Mycobacterium tuberculosis. In this review, we outline the most abundant of over 170 NTM species and inadequacies of diagnostics and treatments and weigh the advantages and disadvantages of currently available in vivo animal models of NTM. In order to effectively combat this group of mycobacteria, more research focused on appropriate animal models of infection, screening of chemotherapeutic compounds, and development of anti-NTM vaccines and diagnostics is urgently needed.

Fig 1. Body sites affected by NTM species.

Pulmonary infections are generally due to inhalation from environmental sources. Disseminated infections are most prevalent in immunocompromised persons, such as those on anti-TNF antibody therapy or suffering from HIV. Cervical lymphadenitis presents most commonly in children. Bone and joint infections by NTM are usually introduced via trauma. Lastly, skin and soft tissue infections are initiated via surgery, trauma, or broken skin barriers contacting contaminated water. Figure represents more commonly encountered species; some less-common species are not depicted. HIV, human immunodeficiency virus; MAC, M. avium complex; NTM, nontuberculous mycobacteria; TNF, tumor necrosis factor.