gms | German Medical Science

Background: Nontuberculous mycobacteria (NTM) are environmental organisms, that can be found in soil, water and animals. They comprise all species other than the obligate pathogens M. tuberculosis and M. leprae.

The association of NTM infection with AIDS has driven the focus to other immunocompromised hosts. However, representative data on NTM infection in these patients are still limited. It is of paramount importance to establish the clinical relevance of a NTM isolate, since the infection and its treatment interfere with the underlying disease and complicate the therapy.

Objective: To describe clinical and microbiological characteristics of patients with malignant disease and concomitant NTM detection and to evaluate the course of disease.

Methods: The laboratory data system was searched for NTM isolates from 10/2012 to 10/2013.

Medical files of all patients, from whom NTM were isolated, were reviewed retrospectively.

Results: In this period we found 9 adult patients, with NTM isolated from the respiratory tract (7 male, 2 female). The patients had a median age of 65 years and the most frequent underlying disease was lymphoma (7/9). Two patients suffered from solid cancers (lung, pancreas). 4 patients died, one was lost to follow up.

NTM species included M. avium complex (MAC) (6/9), M. gordonae (2/9) and M. mucogenicum (1/9). The description of radiologic abnormalities did not meet the American thoracic society (ATS) guideline criteria for NTM lung disease. However, the patterns described as atypical or nodular in 6/9 cases could be assigned to the nodular-bronchiectatic form rather than the fibrocavitary form.

All 6 patients with MAC suffered from lymphoma, 5 of them received steroids at date of MAC diagnosis in two cases there was chemotherapy ongoing. 5/6 patients received combination therapy for MAC infection. 3/6 patients with MAC infection died of respiratory disorder.

Conclusion: In contrast to the statements of the ATS guidelines, where nodular-bronchiectatic MAC lung disease is considered to be more benign with a slower progress, the outcome in our cases was clearly poorer. This is concordant to findings in a study from The Netherlands and may be due to differences in MAC species distribution between USA and Europe. Secondly, predispositioning conditions for MAC lung disease, that is immunosuppression due to malignancy and its therapy, are considerably different in our setting than the populations described in other studies. Our findings add to the observation that MAC identification in patients with malignant diseases should not be neglected. Efficient therapeutic strategies remain to be ascertained.