A Comprehensive Review and Update on Epidemiology, Symptomatology and Management of Nontuberculous Mycobacteria (NTM)

Abstract

Nontuberculous mycobacteria (NTM) are free-living organisms ubiquitously present in the environment. In recent times, NTM gained much importance due to the increase in incidence globally. They are potential agents in causing both pulmonary and extrapulmonary infections in both immunocompromised and immunocompetent individuals. The problem arises when the possible NTM cases are misdiagnosed as drug-resistant tuberculosis (DR-TB). Hence, it is essential to correctly identify the NTMs causing disease due to two major reasons. One is to prevent clinicians from starting anti-tuberculous drugs and the other is that treatment regimen differs for certain NTM from tuberculosis. Apart from conventional methods like smear microscopy, culture, in the current era newer diagnostic modalities like matrix-assisted laser desorption of ionization-time of flight mass spectrometry (MALDI TOF MS), line probe assay, genomic sequencing, are used in referral laboratories which allows identification and speciation of the organism. A thorough literature search was done in PubMed, Google Scholar, Cochrane Library, Embase, Scopus on nontuberculous mycobacteria. The search keywords include nontuberculous mycobacteria, atypical mycobacteria, case reports, and original articles on NTM. In this review, we have summarised the current knowledge on epidemiology, pathogenesis, clinical features, and treatment of NTM.

Mycobacterium abscessus sporotrichoid infection after a dog bite

“…NTM comprise a heterogenous group of acid-fast bacilli that are further classified according to their growth speed, morphology, and pigmentation. 1 They were first described in 1931 by Pinners, and there are now more than 200 reported species. 3 M. abscessus is associated with a wide spectrum of dermatological lesions that include cellulitis, abscesses, papules, pustules, fistulae, ulcers, necrotic lesions, and subcutaneous nodules that can resemble Sporothrix lesions.…”

“…However, antibiotic combination therapy and surgical drainage of the lesions is strongly recommended. 1 , 3 The choice of antibiotics usually involves clarithromycin or azithromycin plus amikacin, cefoxitin, or imipenem for severe infections. Treatment duration may span from 3 to 6 months.…”

“…The terms “atypical mycobacteria” or “non-tuberculous mycobacteria” (NTM) refer to a group of mycobacteria other than Mycobacterium tuberculosis and Mycobacterium leprae . 1 , 2 NTM are ubiquitous organisms that can resist extreme temperature conditions. 1 , 2 M. abscessus is a fast-growing atypical mycobacterium that can cause cutaneous lesions and disseminated infections, typically after skin trauma.…”

“… 1 , 2 NTM are ubiquitous organisms that can resist extreme temperature conditions. 1 , 2 M. abscessus is a fast-growing atypical mycobacterium that can cause cutaneous lesions and disseminated infections, typically after skin trauma. 2 Dermatological manifestations include nodules, abscesses, and ulcers that may often resemble Sporothrix infections.…”

“… 2 Dermatological manifestations include nodules, abscesses, and ulcers that may often resemble Sporothrix infections. 1 Zoonotic transmission is rarely reported. 3 …”