The Emergence of Isoniazid-Resistant Cultures in Patients with Pulmonary Tuberculosis during Treatment with Isoniazid Alone or Isoniazid plus PAS.

摘要: Abstract Previous reports from the Tuberculosis Chemotherapy Centre, Madras, have described a comparison of four regimens (three isoniazid alone and one plus PAS) in treatment pulmonary tuberculosis an investigation serum levels patients concerned. The present report studies emergence isoniazid-resistant organisms these during treatment. All with unsatisfactory response to yielded resistant cultures, showing that dosage was never too low inhibit sensitive organisms. From degree resistance first cultures six-month treated it concluded emerged two stages. In stage, very earlyin treatment, highly mutant bacilli grew freely whatever dosage, but mutants lower were prevented growing extent dependent on peak concentration serum. Consequently, when increased proportion decreased, since fewer low-resistance strains able develop. second relatively continued multiply, though still partially inhibited by isoniazid, became more resistant, particularly slow inactivators. first-stage events determined results since, once had emerged, its unrelated patient's eventual progress. These findings emphasize importance early intensive chemotherapy adjustment according concentrations rather than measured three or six hours after dose. Concomitant administration PAS many others delayed reduced degree, possibly because growth stage slow.