Some thoughts on results following intermittent streptomycin in pulmonary tuberculosis.

The contribution made by streptomycin (SM) towards the success of antituberculous chemotherapy is by now well established. It is not an “all safe, all powerful” drug, as its use can lead to serious consequences. There appears to be some danger from toxicity of the drug itself, but in our experience this has been relatively low. However, the dosage of streptomycin when used intermittently (two or three injections per week) in combination with daily INH and/or PAS is generally inadequate and invites therapeutic failure. This results in the patient’s excreting organisms resistant to one or more of the principal antimicrobial agents. Retreatment is rather difficult, the percentage of success being comparatively low ; and surgery in these patients carries a definite risk of postoperative complications such as bronchopleural fistula and empyema. One sees a number of private physicians and chest hospitals throughout the country using combinations of drugs including biweekly streptomycin, believing this to be “adequate” initial treatment in tuberculosis. The reason is difficult to understand. Papers have been published to confirm the earlier findings of the British Medical Research Council-that intermittent SM with daily INH or PAS is not the treatment of choice in tuberculosis. We have reviewed 108 cases who were admitted to National Jewish Hospital consecutively since 1956, whose sputum was initially positive for typical M. Tuberculosis, and whose previous chemotherapy had included intermittent SM (1 gm. two or three times per week). Positive culture on admission was found in 79 per cent of these cases, and all but five of these were excreting high proportions of tubercle bacilli resistant to SM and/or INH. In 21 per cent of these cases the treatment had been apparently successful and their sputum tests were consistently negative for tubercle bacilli. An additional group of 46 cases was studied whose initial chemotherapy including intermittent SM was started after January 1955 (i.e. after the publication of the M.R.C. findings). Sixty three per cent of these patients were found positive for tubercle bacilli on admission, and all but three were resistant to SM and ‘or INH (Table I). The treatment was started at home for 14 of these patients, and in hospital for 32. Many factors may explain why certain principles are not more widely accepted in the United States, and among these is the fact that reports observed by us in the American literature do not sufficiently stress the superiority of the regimens containing daily SM over all others. One argu-