Mycobacterium malmoense (M. malmoense) is a bacterium naturally found in the environment, such as in wet soil, house dust, water, dairy products, domestic and wild animals, food, and human waste. M. malmoense infections most often occur in adults with lung disease, and manifests as a lung infection. Skin and tissue infections with M. malmoense have also been described. In young children, M. Malmoense may cause an infection of lymphnodes in the neck (i.e., cervical lymphadenitis).