Rare case of Mycobacterium nebraskense presenting as asymptomatic cavitary lung lesion

Abstract

Introduction: Mycobacterium Nebraskense is a rare nontuberculous mycobacterial infection. The first isolate of the species was from human sputum at University of Nebraska Medical Center. There are only a few cases have been reported and the exact behavior of the disease is not clearly described. Here, we present a case from New York City incidentally found to have a cavitary lung lesion due to M. nebraskense. Case report: An 82-year-old female with a history of diabetes mellitus, hypertension, and dementia presented with constipation and urinary retention for 1 day. She had no fever, cough, shortness of breath, nausea, vomiting, appetite change, or weight loss. Computed tomography (CT) scan of abdomen and pelvis revealed retained fecal material in the colon, non-obstructing left renal calculus, and bilateral small pleural effusion with right-sided lung infiltrates. Subsequent CT scan of the chest showed 4.5 cm pleural-based opacity in right lung base with a small cavity. Sputum smear for Acid-fast bacilli was positive. Mycobacterial culture reported positive growth of M. nebraskense, while polymerase chain reaction returned negative for Mycobacterium gordonae, Mycobacterium kansasii, Mycobacterium avium complex and Mycobacterium tuberculosis. With the patient asymptomatic and her constipation improved, she was discharged with plans for close follow-up as outpatient. Conclusion : M. nebraskense is a very rare nontuberculous mycobacterial infection. From only a few cases reported in the USA, the exact presentation of infection, disease progression, and treatment have not been described well. Asymptomatic cavitary lung disease caused by M. nebraskense has not been reported before.

First report of nodular skin lesions caused by Mycobacterium nebraskense in a 9-year-old cat

“…However, one reported case was successfully treated with a combination of rifampin and azithromycin. 16,17 Even though in the present report not all of the nodular skin lesions could be removed with wide surgical margins, spreading of infection along tissue planes was not observed and recurrence of skin disease was not detected 1 year after completion of antimicrobial therapy. Standard criteria for selection of patients requiring surgical intervention are not available.…”

“…14 Previously reported from respiratory specimen from humans, M nebraskense is recognised nowadays as a potential cause of human infections and, in particular, to be associated with pulmonary disease. [15][16][17] Nevertheless its primary source and the route of infection remains unclear and sporadic isolations from water and abattoir environmental samples may suggest a ubiquitous origin of this mycobacterium. 9,18 Feline cutaneous mycobacteriosis is thought to be the result of infected bite or scratch wounds, surgical interventions or lymphohaematogenous spread of the pathogen.…”

“…However, one reported case was successfully treated with a combination of rifampin and azithromycin. 16,17…”