Mycobacterium szulgai: an unusual cause of disseminated mycobacterial infections.

The incidence of nontuberculous mycobacterial infections in the USA has significantly increased during the past three decades, specifically after the advent of HIV/AIDS [1–4]; however, the incidence of tuberculosis in the United States is low when compared to developing countries. For most of the nontuberculous mycobacteria (NTM), the pathogenicity and clinical relevance are poorly understood. Likewise, the role of in vitro susceptibility testing of NTM isolates related to the approach of patient care management remains a topic of debate, despite the fact that consensus guidelines for optimal diagnosis, treatment, and prevention for NTM infections were published in 2007 [5]. This fact is mainly related to the limited number of cases caused by certain NTM species and is further related to some variability in antimicrobial resistance profiles. Mycobacterium szulgai was first described in 1972; since then, it has been repeatedly recognized as a cause of pulmonary infections that often clinically and radiologically resemble patterns of disease caused by M. tuberculosis [6–9]. Based on a recent case of a fatal M. szulgai infection in a patient with disseminated disease and underlying hematologic malignancy in our institution, we reviewed the current literature with regard to epidemiology, diagnosis, and treatment approaches for M. szulgai infections. The infection in our patient was unrecognized for an undetermined amount of time, prior to presentation to our hospital. Our literature review identified only a few case reports and no comprehensive review of the subject was identified. The patient’s current and past medical history: A 59-year-old Caucasian male patient presented to our institution with progressive unintentional weight loss and fatigue over a period of the prior 12 months. The patient’s past medical history was otherwise significant for hypertension, hyperlipidemia, a thyroidectomy for papillary thyroid carcinoma, and a laminoforaminotomy. Two months prior to his current presentation, the patient was diagnosed with an upper respiratory tract infection, for which he was treated with a course of azithromycin. However, there was only marginal improvement of his symptoms. Subsequently, the patient self-medicated with penicillin for an unknown duration and dosing schedule. On a subsequent visit to another emergency room, a chest computed tomography (CT) scan showed bullous changes of the basal lobe of the right lung, a 2.5-cm right hilar lymph node, and a 6-mm precarinal lymph node. At that time, the patient received treatment with oral corticosteroids for the presumptive diagnosis of sarcoidosis. He also required more frequent transfusions with leukoreduced, packed red blood cells (RBC), and weekly Epoetin a injections for a significantly more symptomatic anemia. A colonoscopy, performed as part of the diagnostic work-up for the persistent and recurrent anemia, was without significant pathologic findings. Diagnostic procedures: Upon admission to our hospital, the patient presented with profound anemia: hemoglobin S. Riedel (&) Department of Pathology, Division of Microbiology, The Johns Hopkins University, School of Medicine, Johns Hopkins Bayview Medical Center, 4940 Eastern Avenue; A Building, Room 102-B, Baltimore, MD 21224, USA e-mail: sriedel2@jhmi.edu