Pulmonary disease caused by Mycobacterium malmoense. Comments on the possible origin of infection and methods for laboratory diagnosis.

Mycobacterium malmoense was isolated from sputum and gastric lavage from a 68-year-old man with gastric adenocarcinoma. The patient meets the criteria for diagnosis of pulmonary mycobacteriosis. The cultural, physiological and biochemical properties of the isolates were compared with other slowly growing mycobacterial species. Fatty and mycolic acid analyses revealed the presence of 2-methyleicosanoic and 2,4,6-trimethyltetracosanoic acids and alpha-, alpha'-and ketomycolates, all regarded as typical for M. malmoense. The possible origin of M. malmoense infections and methods for laboratory diagnosis are discussed. This is the first case of documented infection due to this organism in Belgium.