Bactericidal activities of an amphoteric surfactant (12w/v% Alkyl diaminoethylglycine hydrochloride, 3w/v% Alkyl dietylenetriaminoglycole hydrochloride, Nissan Anon #300^®, Inui Shouji Co., ADG) against Mycobacterium tuberculosis were examined independently or in cooperation with ethanol. The results obtained in the study are as follows:
1. In the treatment with the surfactant diluted with distilled water in one hundredth, the numbers of tubercle bacilli which survived were 500cfu/0.1ml after one minute-treatment, and 25cfu/0.1ml after ten minutes-treatment. On the other hand, the surfactant containing 23v/v% ethanol decreased the bacterial numbers to seven cfu/0.1ml after one minute and less than one cfu/0.1ml after ten minutes. The numbers of the survived bacilli treated with the surfactant containing 20v/v% ethanol were 500cfu/0.1 ml after one minute-treatment, and less than one cfu/0.1ml after ten minutes though 20v/v% ethanol alone was ineffective in ten minutestreatment.
2. The bactericidal activities of the surfactant against tubercle bacilli in sputum samples in which 1.65×10⁴cfu/0.1ml of the organism were contained were also investigated. The numbers of tubercle bacilli which survived were 25cfu/0.1ml after one minute-treatment with the surfactant in one fiftieth, two cfu/0.1ml after five minutes-treatmnet and one cfu/0.1ml after ten minutes-treatment. The numbers of the organism treated with the surfactant containing 23v/v% ethanol were less than one cfu/0.1ml after five minutes.
3. When the scanning electoron microscopies were performed, it was observed that the cell-surface of the organisms exposed to the surfactant in one fiftieth and the surfactant containing 23v/v% ethanol became to sticky and fusible. The morphological chang was greater in the former than in the later.
Those findings indicate that the bactericidal activity of the surfactant against M. tuberculosis is enhanced by cooparation with ethanol.