Non-Tuberculous Mycobacteria: Molecular and Physiological Bases of Virulence and Adaptation to Ecological Niches

Abstract

Non-tuberculous mycobacteria (NTM) are paradigmatic colonizers of the total environment, circulating at the interfaces of the atmosphere, lithosphere, hydrosphere, biosphere, and anthroposphere. Their striking adaptive ecology on the interconnection of multiple spheres results from the combination of several biological features related to their exclusive hydrophobic and lipid-rich impermeable cell wall, transcriptional regulation signatures, biofilm phenotype, and symbiosis with protozoa. This unique blend of traits is reviewed in this work, with highlights to the prodigious plasticity and persistence hallmarks of NTM in a wide diversity of environments, from extreme natural milieus to microniches in the human body. Knowledge on the taxonomy, evolution, and functional diversity of NTM is updated, as well as the molecular and physiological bases for environmental adaptation, tolerance to xenobiotics, and infection biology in the human and non-human host. The complex interplay between individual, species-specific and ecological niche traits contributing to NTM resilience across ecosystems are also explored. This work hinges current understandings of NTM, approaching their biology and heterogeneity from several angles and reinforcing the complexity of these microorganisms often associated with a multiplicity of diseases, including pulmonary, soft-tissue, or milliary. In addition to emphasizing the cornerstones of knowledge involving these bacteria, we identify research gaps that need to be addressed, stressing out the need for decision-makers to recognize NTM infection as a public health issue that has to be tackled, especially when considering an increasingly susceptible elderly and immunocompromised population in developed countries, as well as in low- or middle-income countries, where NTM infections are still highly misdiagnosed and neglected.

COVID-19 vaccine development based on recombinant viral and bacterial vector systems: combinatorial effect of adaptive and trained immunity

“…There are more than 150 species within the genus Mycobacterium, including strict human pathogens such as M. tuberculosis and M. leprae, and nontuberculous mycobacteria (NTM) with lower pathogenic potential, most of which exist in the environment (Pereira et al, 2020). Mycobacteria have a thick lipid-rich cell wall, and the cell wall components can act as strong vaccine adjuvants to elicit innate cell activation.…”

Non-Tubercle Mycobacteria and Other Contaminants in Metalworking Fluids from Small Turneries

“…Microbial contaminants are introduced into MWF through make-up water, previous contamination of MWF system, workers, air, microorganisms on incoming parts, and external contamination (Passman and Küenzi 2020; NIOSH 1998). It is of importance to note that NTM have been frequently isolated from soil (Pereira et al 2020). The turneries in Jordan are small shops that keep their doors open all day.…”

Stringent Response in Mycobacteria: From Biology to Therapeutic Potential

“…Thus, the stringent response regulates biofilm in mycobacteria by regulating the expression of genes involved in GPL and other cell wall components. Since NTMs utilize biofilm formation to establish infections, given their ability to form biofilms on medical implants and water distribution systems, it is very important to also explore the role of stringent response in NTM species [105,120,121].…”