Mycobacterium tuberculosis infection in allogeneic bone marrow transplantation patients

Bone marrow transplant (BMT) recipients are prone to bacterial, viral and fungal infections. Mycobacterium tuberculosis infection can occur in these patients, but the incidence is lower than that of other infections. This report describes four patients with Mycobacterium tuberculosis infection identified from 641 adult patients who received a BMT over a 12-year period (prevalence 0.6%). The pre-transplant diagnosis was AML in two patients and CML in the other two. Pre-transplant conditioning consisted of BU/CY in three patients and CY/TBI in one. Graft-versus-host disease (GVHD) prophylaxis was MTX/CsA in three patients and T cell depletion of the graft in one patient. Sites of infection were lung (two), spine (one) and central nervous system (one). Onset of infection ranged from 120 days to 20 months post BMT. Two patients had co-existing CMV infection. One patient had graft failure. The two patients who received anti-tuberculous (TB) therapy recovered from the infection. Although the incidence of tuberculosis in BMT patients is not as high as in patients with solid organ transplants, late diagnosis due to the slow growth of the bacterium can lead to delay in instituting anti-TB therapy. A high index of suspicion should be maintained, particularly in endemic areas.