Mycobacterium Arupense in Cancer Patients: A Commensal Organism or a Pathogen?
Methods: We retrospectively identified all cancer patients treated at our institution between January 1, 2007, and June 30, 2012, who had at least one positive sputum sample, bronchoalveolar lavage (BAL), or sterile body fluid culture for M. arupense. M. arupense was identified by sequencing the 16S rRNA and hsp65 genes. Definite cases of M. arupense were defined according to nontuberculous mycobacterial disease (NTM) clinical and microbiologic criteria from the American Thoracic Society (ATS) / (IDSA). Other cases were classified as probable, possible and colonizer. We compared the outcomes of patients who did or did not receive treatment for M. arupense infection.
Results: We identified 36 patients with positive cultures for M. arupense; of these patients, 7 received treatment for M. arupense infection and 29 did not. Six patients met the ATS/IDSA criteria for the definitive diagnosis of nontuberculous mycobacterial disease. The two groups’ baseline clinical characteristics did not differ significantly. M. arupense was isolated from sputum (18 patients [50%]), BAL samples (17 [47%]), and pelvic fluid (1 [3%]). The outcomes of the treated and the untreated patients did not differ significantly; clinical symptoms improved in 86% of treated patients and 67%of untreated patients (P=0.76). Similarly, radiological findings showed improvement in 67% and 57% of the patients in each group, respectively (P=0.99). There were no relapses of M. arupense infection. In addition, there were no M. arupenserelated mortalities in either group.
Conclusion: In cancer patients, M. Arupense seems to be mostly a commensal organism rather than a pathogen. Patients who did or did not receive treatment had similar outcomes. Further assessments to validate these findings in a larger trial are warranted.
Z. Alhamal, None
A. M. Chaftari, None
Y. Jiang, None
R. Hachem, None
I. Raad, None