Waksman — 1 30 — Actinomycetes 



The fact that certain actinomycetes are capable of producing more 

 than one antibiotic frequently tends to confuse the recognition of the 

 identity of any single constituent. The literature on the antibiotics 

 produced by actinomycetes continues to accumulate rapidly. New 

 agents are being isolated, as in the case of the pigmented substances 

 actinorhodin (46a) and actinomycelin (66a). New light is being 

 thrown upon the composition and activity of agents previously an- 

 nounced, as in the case of neomycin (179a, 469a). New fractions are 

 being isolated from older agents, as in the case of antimycin A (lOll?) 



Dai^s c^ /ncuba-tion S lO 



Rate, o/: Gnov\/th 



Sacterioly tic Activ-itu 



Fig. 29.— The course of development of S. a\hui and bacteriolytic activity of the 

 culture filtrate, actinomycetin Cf^om Welsch, 505). 



and neomycin A (332a). New methods are being developed for the 

 isolation and purification of unknown agents (461?). 



Antibiotics of actinomycetes and chemotherapy.— Among the various 

 antibiotics produced by actinomycetes, some have already occupied a 

 prominent place as chemotherapeutic agents. It is sufficient to mention 

 streptomycin, aureomycin, and Chloromycetin. The most important 

 applications are their use in the treatment of infections caused bv gram- 

 negative bacteria, infections by gram-positive bacteria made resistant to 

 penicillin, rickettsial infections, and tuberculosis. 



Several volumes have alreadv been devoted to the clinical use of 

 streptomycin. A most extensive literature has accumulated on the use 

 of streptomycin covering nearly 2,000 titles. Comprehensive surveys 



