Affiliation:
1. University Department of Bacteriology, Royal Infirmary, Glasgow
Abstract
A study was made of cases of tuberculosis treated by chemotherapy in Eastern Glasgow between 1963 and 1968 which developed drug-resistant bacilli. The commonest resistance pattern was to the combination of 3 drugs—streptomycin, p-aminosalicylic acid (P.A.S.) and isoniazid in contrast to resistance to streptomycin alone which predominated 12 years ago. In strains from 6 patients no less than 6 drugs had become ineffective. Experiments with Escherichia coli confirmed that the ‘high mutation rate’ in the presence of streptomycin, which is characteristic of other tuberculostatic drugs also, is attributable to predictable and progressive mutations. Six examples are given where outbreaks of cross-infection by drug-resistant bacilli can be assumed.