Inhibitory Action of Ethyl Mercaptan on Intracellular Tubercle Bacilli

Abstract

WE have previously described the anti-tuberculous activity in mice of ethyl mercaptan and its derivatives^1,2. The marked activity which was observed did not seem to correspond with the slight bacterio-static action of ethyl mercaptan against Myco-bacterium tuberculosis in vitro. Since the bacilli in tuberculosis are intracellular, we decided to test the effect of ethyl mercaptan against bacilli so located. For this purpose we used the method described by Suter³ in which tubercle bacilli are grown in vitro within monocytes derived from peritoneal exudates of normal guinea pigs. Because of the high volatility of ethyl mercaptan it was necessary to modify Suter's method of incubating the cover-slips on which the monocytes and bacteria were attached. The tubes containing the cover-slips were sealed by heat before they were incubated, at an angle of 30° from the vertical, without rotation. This modification still allowed good growth of the bacteria and isoniazid was highly effective (Table 1).