Molecular Confirmation of Bacillus Calmette-Guérin as the Cause of Pulmonary Infection Following Urinary Tract Instillation

Instillation into the urinary tract of the bacillus Calmette-Guérin (BCG), a strain of Mycobacterium bovis, is associated only rarely with severe side effects. We report here two cases of culture-proven pulmonary infection due to therapy with BCG. The first patient, who was seropositive for the human immunodeficiency virus, developed bilateral interstitial pneumonitis after instillation of BCG into the bladder. The second patient developed a right-lower-lobe infiltrate and empyema after instillation of BCG into the right renal pelvis. The clinical isolates from these two patients and from a third patient with a psoas abscess following intravesical instillation were analyzed with use of pulsed field gel electrophoresis (PFGE) to resolve chromosomal restriction fragment polymorphisms. The clinical isolates were confirmed to be BCG by comparison with known vaccine strains that differed from M. bovis isolates. We conclude that the potential for subsequent dissemination be considered prior to the intravesical administration of BCG. Analysis with PFGE may be useful for identifying species of the Mycobacterium tuberculosis complex.