General Overview on Nontuberculous Mycobacteria, Biofilms, and Human Infection

Abstract

Nontuberculous mycobacteria (NTM) are emergent pathogens whose importance in human health has been growing. After being regarded mainly as etiological agents of opportunist infections in HIV patients, they have also been recognized as etiological agents of several infections on immune-competent individuals and healthcare-associated infections. The environmental nature of NTM and their ability to assemble biofilms on different surfaces play a key role in their pathogenesis. Here, we review the clinical manifestations attributed to NTM giving particular importance to the role played by biofilm assembly.

Figure 1

NTM persist in a steady state between planktonic (a) and biofilm (b) within healthcare units and on medical devices. Biofilm assembly is triggered by environmental stress. Bacteria organized in biofilm exhibit a different structure being notorious, increasing the amount of extracellular matrix (red arrows). Another feature of these bacteria is the increased resistance to chemical sterilization, which leads to persistence within healthcare units, host colonization, and onset of disease. (Red circles: dead bacteria; green circles: live bacteria; scale bar 1 μm.)