Concomitant or sequential pulmonary infection with non-tuberculous mycobacteria and Aspergillus

Non-tuberculous mycobacteria (NTM) and Aspergillus are ubiquitous organisms that have the potential to cause significant pulmonary disease in certain clinical contexts. An association is known to exist between NTM and Aspergillus lung infections. However, it is unclear if NTM infection predisposes to Aspergillus infection or vice versa. It is also unclear whether treatment for one results in a favourable ecological niche that facilitates the growth of the other and promotes subsequent clinical disease. An improved understanding of the link between these two pulmonary pathogens is critical to guide improvements in clinical practice, and ultimately, enhance outcomes among patients who are at risk of experiencing these infections, either concomitantly or sequentially. Here, we discuss the association between pulmonary NTM and Aspergillus infections. We address the frequency with which coinfection or sequential infections are reported to occur, predisposing risk factors that have been identified and the impact on clinical outcomes. Current data on the mechanistic links between NTM and Aspergillus lung infections are also considered. The potential implications for routine clinical practice are explored.