Nontuberculous Mycobacteria: An Update on Infections Caused, Laboratory Identification and their Treatment

Abstract

Nontuberculous mycobacteria (NTM) or mycobacteria other than tuberculosis (MOTT) are opportunistic environmental pathogens capable of causing different kinds of infections to humans starting from hospital acquired to pulmonary and soft tissue infections. They share the common genera Mycobacterium tuberculosis (Mtb) and Mycobacterium leprae, the causative agents of two major diseases, tuberculosis (TB) and leprosy, respectively. Although NTMs or MOTT are similar to Mtb and M. leprosy in terms of mycolic acid-containing cell wall, acid fastness and their capability of causing pulmonary and extrapulmonary diseases, they are highly dissimilar in terms of growth rate and their antibiotic resistance profile. Several clinically relevant NTM strains are inherently resistant to different classes of antibiotics including the first line of drugs (e.g. isoniazid, rifampicin and pyrazinamide) used for treatment of TB. Currently, NTM infections have become a major concern to mankind in terms of mortality and morbidity in immunocompromised individuals. In addition, lack of antibacterial molecules, specific diagnostic tools and their intrinsic resistance to common antibiotics have turned these historically neglected pathogens to serious threats. In this chapter, we have discussed about infections caused by different NTMs, their laboratory identification and the antibiotics available to treat these infections.