Disseminated nontuberculous mycobacteria infection in an immunocompetent host: A case report

RATIONALE

Disseminated nontuberculous mycobacterial (NTM) infections are rare and occur primarily in immunocompromised hosts. Mycobacterium abscessus complex (MABC), including M abscessus subsp. massiliense (hereafter M massiliense) is a complex of rapidly growing mycobacterial (RGM) species of NTM. Here, we present a rare case of disseminated NTM infection with RGM bacteremia caused by M massiliense in an immunocompetent host.

PATIENT CONCERNS

A 64-year-old woman with a recent history of spine fracture and septic pneumonia was transferred to our emergency room for dyspnea and fever. A peripherally inserted central catheter (PICC) had been placed over 6 months prior.

DIAGNOSES

Chest computed tomography (CT) showed multifocal patchy consolidations and ground-glass opacity in both lungs. NTM suspected of RGM was isolated from the blood cultures. During hospitalization, multiple erythematous and hemorrhagic crusted nodules developed on the patient's upper and lower extremities, which were confirmed as disseminated NTM infection on skin biopsy.

INTERVENTIONS

After NTM suspected of RGM was isolated from the blood cultures, the patient was empirically treated with antibiotics used for NTM infection, and the PICC was removed. Thereafter, the subspecies of NTM was reported as M massiliense and she was treated according to the antibiotic susceptibility testing results.

OUTCOME

Although skin lesions and inflammatory markers improved gradually during antibiotic treatment over 10 weeks, NTM could still be isolated from the blood culture.

LESSONS

Disseminated NTM infections with RGM bacteremia in an immunocompetent host have rarely been reported. In this case, PICC placement for more than 6 months was suspected to be an important risk factor for RGM bacteremia in an immunocompetent patient. To date, there are only insufficient case reports, moreover no clear guidelines regarding the optimal choice of antibiotics or length of treatment for disseminated NTM infection. Therefore, it is necessary to establish treatment guidelines for patients with disseminated NTM infection and bacteremia.

Endobronchial Lesions from Disseminated Mycobacterium avium Infection in a Patient with Anti-interferon-gamma Autoantibodies

A 78-year-old man was admitted to our hospital with a fever and left chest pain. Computed tomography showed multiple lung nodules, narrowing of the right bronchus intermedius with mediastinal lymphadenopathy, and an osteolytic lesion. Bronchoscopic findings showed rapid progression of multiple polypoid lesions and the bronchial stenosis. A biopsy of the endobronchial lesions revealed non-necrotizing granulomatous inflammation, and a tissue culture identified Mycobacterium avium. An anti-human immunodeficiency virus antibody was negative. Finally, anti-interferon-gamma (IFN-γ) autoantibodies were detected, and the patient was diagnosed with disseminated nontuberculous mycobacterium infection with anti-IFN-γ autoantibodies. Antimycobacterial therapy was effective, and radiographic findings, including the endobronchial lesions, were resolved.