Pharmacological study of a new antibiotic of bacillary origin.

The purified extract of a new bacterial mutant, which exhibits antibiotic activity against paramecia and amoebae, was tested on various smooth muscle preparations. Spontaneous activity as well as the response to a variety of smooth muscle stimulants was diminished or completely suppressed. Intravenous injection of the extract lowered the blood pressure of the anaesthetized cat or dog. These properties may explain the beneficial effect of the extract on the intestinal symptoms of human amoebiasis, before eradication of the parasites.