Human-to-human transmission of Mycobacterium kansasii or victims of a shared source?

Abstract

To the Editor: Nontuberculous mycobacteria (NTM) are ubiquitous in the environment [1] and can cause opportunistic infections in humans with either an immunological deficit or structurally abnormal lungs, such as in cystic fibrosis, bronchiectasis or chronic obstructive pulmonary disease (COPD) [2]. Unlike Mycobacterium tuberculosis , human-to-human transmission of NTM is generally thought to be uncommon [2–4], although there is evidence that transmission of certain NTM is possible in certain circumstances [5]. Domestic plumbing has also been suggested as a potential source of infection [6]. We describe what we believe to be the best evidence to date of human-to-human transmission of Mycobacterium kansasii in a husband and wife living in East London, UK, an area with a high incidence of tuberculosis (∼112 cases per 100 000 per year) [7]. A recent survey suggested a UK isolation rate for NTM of around three cases per 100 000 per year with no data available for true disease incidence [8]. The first of the couple to be seen in chest clinic was a 69-year-old Caucasian …