Nontuberculous mycobacteria (NTM) are found throughout our environment and infection is thought to occur through acquisition from environmental sources such as soil and water [1]. However, recent studies have reported that many people with cystic fibrosis (CF) share one of several dominant circulating clones, suggesting the possibility of transmission between individuals, perhaps in healthcare facilities [2–4]. Indeed, several studies have reported the possibility of person-to-person transmission of NTM in people with and without CF in the healthcare setting [2, 5–19]. Most of these studies have investigated healthcare-associated transmission of Mycobacterium abscessus and Mycobacterium abscessus subspecies massiliense in the context of CF care centres and they have reported conflicting results, although most concluded that person-to-person transmission was uncommon and does not explain how most people with CF acquire infection.