Cluster of non-tuberculous mycobacteraemia associated with water supply in a haemato-oncology unit.

Non-tuberculous mycobacteria (NTM) are ubiquitous environmental organisms but rarely cause infections. Clinical, microbiological and epidemiological investigations and subsequent management of a cluster of NTM bacteraemia on a haemato-oncology unit are reported. From October 2007 to July 2008, five patients being managed for haematological malignancies developed pyrexia and general malaise. Mycobacterium mucogenicum (four patients) and Mycobacterium neoaurum (one patient) were identified from their blood cultures. The environment, in particular the water system, was investigated to identify the source of the infection and multiple water samples were cultured according to established criteria. NTM were also isolated from the hospital water system. Central venous catheters (CVCs) were removed and the patients were successfully treated with antibiotics. Environmental measures and changes in CVC care were introduced to prevent further episodes of NTM bacteraemia in these patients. Despite these measures, NTM continued to be present in the water system, but new clinical cases were not identified. NTM are common environmental organisms and are recognized as being difficult to remove from water systems. CVCs were presumed to be the portal of entry in this cluster of NTM bacteraemia, and the implementation of changes to CVC care protocols was successful in preventing further infections in this immunocompromised patient group.