Aim and Background. Patients with hematological malignancies are at higher risk for mycobacterial and many other opportunistic infections due to immunosuppression that resulted from dysfunctional blood cells and chemotherapy-induced depletion in cells of immune system. This study was performed to evaluate the frequency and contributing factors for mycobacterial infections in patients with hematological malignancies according to the both culture and PCR methods on bone marrow aspiration.

Materials and Methods. In this cross-sectional descriptive study, 96 patients with hematological malignancies attending to tertiary health care centers in 2009 and 2010 were enrolled. The bone marrow aspiration was cultured and also evaluated by PCR method.

Results. The mean age of the patients was 39.49 years and 64.6 percent were male. Acute myeloblastic leukemia (23.3%), acute lymphoblastic leukemia (19.2%), and multiple myeloma (17.8%) were the most common malignancies. The cultures of bone marrow aspiration were negative for mycobacterium species in all patients but nucleic acid of this bacterium was detected by PCR method in three cases (3.1%) including two patients with acute lymphoblastic leukemia and one patient with multiple myeloma. Aspergillus, streptomyces, and brucella species.were found in culture of two, one, and two patients, respectively. The age, sex, type of malignancy, and bone marrow transplantation had no effect on PCR results (P > 0.05).

Conclusions. The frequency of mycobacterial infections in patients with acute lymphoblastic leukemia and multiple myeloma may be higher than other hematological malignancies. However for decreasing the morbidity and mortality in these patients monitoring of bone marrow aspiration for mycobacterial and other opportunistic infections is suggested.