Topic:The Recovery of Mycobacterium avium-intracellulareComplex (MAC) from the Residential Bathrooms of Patients with Pulmonary MAC 

ABSTRACT:The distribution of Mycobacterium avium-intracellulare complex (MAC) in residences was examined. MAC was only recovered from bathrooms but not from other sites of residences. The appearance ratio in the bathrooms of patients with pulmonary MAC was significantly higher than that in healthy volunteers' bathrooms (P = .01).

The Mycobacterium avium-intracellulare complex (MAC) is an opportunistic pathogen. However, MAC occasionally causes a progressive lung disease, leading to death, even in patients without a history of lung diseases or immunodeficiency [1]. MAC is widely distributed in rivers, soil, birds, farm animals, public pools, hot tubs, and hot water supplies [2]. In the absence of proof of person-to-person spread of MAC, it is now generally accepted that environmental sources are the reservoir for most human infections caused by MAC [1, 2]. The number of cases of pulmonary MAC disease has been increasing in many countries, especially in advanced countries rather than in developing countries [2]. O'Brien et al. [3] hypothesized that the increased prevalence of MAC lung disease relates to the change in our hygiene habits from bathing to showering. However, the distributions of MAC in individual residences have not been examined. Therefore, we investigated the distribution of MAC in residences to assess the hypothesis of O'Brien and colleagues. Furthermore, we compared the recovery ratio between patients' and healthy volunteers' houses. We also compared the isolates recovered from patients' houses with those from their respective sputum samples using restriction fragment—length polymorphism and PFGE.