Prosthetic joint infection: an extremely rare complication of intravesicular BCG therapy.

A 66-year-old man was seen in clinic due to concerns of tuberculosis of the right hip. He had a history of urothelial bladder carcinoma, which was treated via transurethral resection followed by intravesicular instillations of Mycobacterium bovis BCG (BCG). A few months later, he developed slowly worsening pain over his prosthetic right hip, and it was recommended he undergo surgical revision. During surgery, joint effusion was noted and synovial fluid was sent for bacterial and mycobacterial cultures, growing an acid-fast bacillus after 3 weeks, identified as Mycobacterium tuberculosis complex via nucleic acid probe. Susceptibility testing revealed resistance to pyrazinamide, which is typically seen in M. bovis PCR confirmed the diagnosis of BCG infection. The patient was treated with isoniazid, rifampin and ethambutol, which he tolerated well. This case highlights the challenges associated with diagnosis and management of this rare complication of a commonly used therapy.