The prevalence of drug-resistant tubercle bacilli in untreated patients with pulmonary tuberculosis: A national survey, 1955–56

Abstract

Summary The findings of a survey to assess the prevalence in England, Wales and Scotland of bacillary resistance to streptomycin, PAS and isoniazid among newly diagnosed and previously untreated cases of pulmonary tuberculosis are reported. A representative sample of 80 chest clinics, selected by a random process, participated in the survey, and with the co-operation of their chest physicians 1,404 sputum specimens, from the same number of patients, were cultured at a central laboratory. The collection of specimens started on June 15, 1955, and ended on March 8, 1956. Sensitivity tests to streptomycin, PAS and isoniazid were undertaken on all positive cultures. Of the 974 positive cultures obtained, 50 (5·1 per cent) were resistant to one or more of the three anti-tuberculosis drugs; 44 (4·5 per cent) yielded Myco. tuberculosis; and 6 (0·6 per cent) yielded resistant atypical mycobacteria. Of the 44 resistant strains of Myco. tuberculosis, 22 (2·3 per cent) were resistant to streptomycin, 21 (2·2 per cent) to PAS and 7 (0·7 per cent) to isoniazid; 5 of the strains showed resistance to more than one of the drugs. Those patients found to be infected with resistant organisms were further investigated; their contact histories were compared with those of a similar group of patients derived from those patients infected with sensitive organisms. For each drug separately more of the resistant group than of the sensitive group were known to have been in contact with cases treated with the drug. Definite evidence of contact with organisms resistant to the relevant drug was obtained for 3 of the 22 patients infected with streptomycin-resistant organisms, for 5 of the 21 patients with PAS-resistant strains and for 2 of the 7 patients with isoniazid-resistant strains. No evidence of contact with resistant organisms was found in the matched sensitive group. The clinical, radiographic and bacteriological progress in the two groups of patients are at present being compared and the findings will be reported later.