The possible influence of antibiotics on results of bacillus Calmette-Guérin intravesical therapy for superficial bladder cancer.

Intravesical treatment with Bacillus Calmette-Guérin is an established treatment of carcinoma in situ and an effective prophylaxis for the prevention of recurrence of transitional cell carcinoma. During instillation therapy oral antibiotics may be used to prevent or to treat urinary tract infections. Tuberculostatic agents are employed to prevent or to treat local irritative symptoms and systemic side effects caused by Bacillus Calmette-Guérin. We investigated the susceptibility of four different Bacillus Calmette-Guérin preparations to 18 antibiotics and to 11 tuberculostatic agents in vitro. All preparations were equally susceptible to most of the commonly used antibiotics and to all of the tuberculostatic agents with the exception of pyrazinamide. Our results suggest that in the absence of cystitis, instillations should not be accompanied by antibiotics because of the possible inhibition of antitumor efficacy by eradication of living Bacillus Calmette-Guérin organisms. The same inhibition may occur when tuberculostatic agents are used to prevent local and systemic complications of Bacillus Calmette-Guérin instillation therapy.