[Diagnosis and treatment of pulmonary infection due to Mycobacterium malmoense]

To date more than 150 patients with Mycobacterium malmoense disease have been reported. These infections are rare and only in one case, so far not published, is this species associated with Aids. Most reported cases were seen in northern Europe. We present three pulmonary cases from Switzerland. M. malmoense causes lung disease resembling tuberculosis clinically and in chest X-ray. Disease is considered to be present when two and more sputums or bronchial washings are acid-fast bacilli smear-positive and culture-positive. M. malmoense grows slowly on egg-based bacteriological media; the incubation time is at least 6 weeks and the use of special solid or liquid media is recommended. Person-to-person transmission is rare and, in contrast to tuberculosis, isolation of the patient is not necessary and subsequent close contact persons do not need to be evaluated. It seems that a combination of isoniazid, rifampicin and ethambutol given for more than 12 months is the best regimen.