ANTIBACTERIAL EFFECTS 



133 



that Is active largely against gram-positive organisms (935) and glio- 

 toxin (331, 593). Helvolic acid, isolated from a strain of A. fumigatus 

 (116, 155) was found (593, 933) to be identical with purified fumi- 

 gacin. 



Fumigacin is active against S. aureus in dilutions of i : 200,000 to 

 1:750,000 and is very stable. The pigment fumigatin, however, was 

 said to deteriorate on standing, inhibition of S. aureus being reduced 

 from 1 : 50,000 to 1 125,000 in 7 days. Fumigacin has a certain degree 

 of resistance to high temperatures. Boiling in aqueous solution for 5 to 

 10 minutes reduced but did not destroy completely its activity. Heat- 

 ing at 80° C. for 15 minutes reduced the activity only slightly. When 

 fumigacin was dissolved in alcohol and precipitated by addition of nine 

 volumes of water, the alcohol-water solution was found to contain 0.25 

 mg. per ml. A comparison of the antibacterial activity of fumigacin with 

 that of the other substances produced by A. fumigatus is given in 

 Table 28. 



TABLE 28. CHEMICAL PROPERTIES AND BACTERIOSTATIC ACTIVITY OF FOUR 

 ANTIBIOTIC SUBSTANCES PRODUCED BY ASPERGILLUS FUMIGATUS 



MELTING 

 CRYSTALLI- POINT 



SUBSTANCE ZATION ° C. FORMULA 



BACTERIOSTATIC ACTIVITY 

 IN DILUTION UNITS 



B. sub- 

 E. coli S. aureus tills 



Spinulosin Purplish-bronze 



plates 201 CgHgOg 



Fumigatin Maroon-colored 



needles 116 CgHgO^ 



Fumigacin Very fine white 



needles z 15-220 CgsH^^Og 



Gliotoxin Elongated 



plates 195 C13H14O4N2S2 6,000 1,500,000 750,000 



1,200 200,000 40,000 

 1,200 2,000,000 100,000 



Vaudremer (912) reported that a group of patients suffering from 

 tuberculosis were treated with extracts of A. jumigatuSy with varying 

 degrees of success. The disease-producing organism (M. tuberculosis) 

 was rendered nonpathogenic by such treatment. 



