Mycobacterium bovis BCG causing vertebral osteomyelitis (Pott's disease) following intravesical BCG therapy

We report a ease of Mycobacterium bovis BCG vertebral osteomyelitis in a 79 -year-old man 2.5 years after intravesical BCG therapy for bladder cancer. The recovered isolate resembled M. tuberculosis biochemically, but resistan ce to pyrazinamide (PZA) rendered that diagnosis suspect. High-pressure liq uid chromatographic studies confirmed the diagnosis of M. bovis BCG infecti on. The patient was originally started on a four-drug antituberculous regim en of isoniazid, rifampin, ethambutol, and PZA. When susceptibility studies were reported, the regimen was changed to isoniazid and rifampin for 12 mo nths. Subsequently, the patient was transferred to a skilled nursing facili ty for 3 months, where he underwent intensive physical therapy. Although ex travesical adverse reactions are rare, clinicians and clinical microbiologi sts need to be aware of the possibility of disseminated infection by M, bov is BCG in the appropriate setting of clinical history, physical examination , and laboratory investigation.