First report of Mycobacterium nebraskense as a cause of human infection

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

Case summary

A 9-year-old cat was referred with multiple, raised, ulcerative skin nodules in the region of the neck and dorsal head. Histopathological findings of a biopsied nodule were granulomatous dermatitis and panniculitis without multinucleated giant cells or caseous necrosis. In addition, by Ziehl–Neelsen staining numerous acid-fast intracellular bacilli were observed within the lesions. Mycobacterial culture showed growth of rough scotochromogenic colonies after 3 weeks of incubation. Molecular characterisation of the isolate identified Mycobacterium nebraskense as the cause of the infection. No phenotypic resistance was detected for the antimycobacterial agents tested. The cat was successfully treated with a combination of surgical excision and a 12 week course of antimicrobial therapy, including rifampicin combined with clarithromycin.

Relevance and novel information

To our knowledge, this is the first documented case of mycobacterial granulomatous dermatitis and panniculitis due to M nebraskense infection in a cat. The successful surgical and antimycobacterial treatment regimen is described.

Rare case of Mycobacterium nebraskense presenting as asymptomatic cavitary lung lesion

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.

Molecular identification of Mycobacterium chimaera as a cause of infection in a patient with chronic obstructive pulmonary disease

This report describes a case of Mycobacterium chimaera infection in a patient with a history of chronic obstructive pulmonary disease where the organism was identified by using molecular methods. M. chimaera was identified from fresh lung tissue and from an instrument-negative mycobacterial growth indicator tube broth culture. The utility of using sequence analysis of the internal transcribed spacer region for the rapid identification of a slow-growing nontuberculous Mycobacterium spp. where conventional culture methods were not successful was shown.