Beyond the bladder: case series of <i>Mycobacterium bovis</i> bacillus Calmette-Guérin infections following intravesical instillation

ABSTRACT Intravesical instillation of Mycobacterium bovis bacillus Calmette-Guérin (BCG) was first used to treat bladder cancer in 1976. Since then, it has become a common therapy for non-muscle invasive bladder cancer. A live, attenuated mycobacterium, M. bovis BCG causes infectious complications in approximately 1% of patients. These infections can involve various anatomic sites and have a range of presentations. Diagnosis may require several testing modalities, and treatment typically involves multiple antimicrobials for a long duration. We report three cases of M. bovis BCG infection following intravesical BCG instillation for the treatment of bladder cancer. The patients are men ranging in age from 71 to 83 years old. One had a ruptured mycotic aneurysm of the aorta, another had a presumed anaphylactic reaction, and the final had a bone marrow infection. Isolation of BCG was achieved through mycobacterial blood culture in two cases and also through mycobacterial culture of bone marrow and hematoma aspirate. Nucleic acid amplification testing for Mycobacterium tuberculosis complex (of which BCG is a member) was utilized in two cases, and histologic examination identified granulomas in one case. Two of the patients received mycobacterial treatment, including rifampin, isoniazid, ethambutol, and linezolid. One patient remains living over 3 years after infection, one died despite treatment, and one died from unrelated causes. These cases highlight the diversity of BCG infection symptoms and sites and the various laboratory testing modalities that can inform diagnosis and treatment.