Mycobacterium chimaera Disseminated Infection

Area of Science:

• Infectious Diseases
• Medical Microbiology
• Immunocompromised Hosts

Background:

• Nontuberculous mycobacterial (NTM) diseases are increasing, necessitating accurate species identification for effective treatment.
• Molecular microbiology techniques enhance understanding of NTM pathogenicity and treatment responses.
• Immunocompromised patients, particularly those with hematologic malignancies, are at higher risk for disseminated NTM infections.

Observation:

• A 57-year-old man with B-cell lymphoma developed fever, night sweats, and asthenia, progressing to pneumonia, anemia, and hepatosplenomegaly.
• Blood, bronchoalveolar lavage, and bone marrow cultures revealed disseminated *Mycobacterium avium-intracellulare* complex infection.
• Initial empirical antibiotics were ineffective, requiring a multi-drug regimen.

Findings:

• Species identification using the GenoType NTM-DR test confirmed *Mycobacterium chimaera* (MC).
• A four-drug regimen (clarithromycin, rifabutin, ethambutol, and moxifloxacin) was effective, with slow but gradual clinical improvement.
• Treatment led to negative cultures after 4 months and was continued for 12 months, demonstrating successful infection control.

Implications:

• This case highlights the successful use of molecular diagnostics for rapid and accurate identification of MC.
• A four-drug regimen can effectively treat severe, disseminated MC infections in immunocompromised individuals.
• Despite successful infection treatment, underlying conditions like B-cell lymphoma relapse can impact patient outcomes.