ISOLATION AND IDENTIFICATION OF ANTIBIOTICS 



47 



the practical potentialities of freshly isolated 

 antibiotics. 



In view of the rapidl}' accumulating in- 

 formation concerning the large number of 

 actinomycetes capable of producing anti- 

 biotics under certain conditions, and in view 

 of the numerous new antibiotics constantly 

 being isolated in various laboratories 

 throughout the world, no final system of 

 classification can be proposed at the present 

 time. The chemical nature of the substances, 

 supplemented by a knowledge of the range 

 of their antimicrobial activities, offers a good 

 basis for a tentative system of classification, 

 as outlined in detail in Fart B. 



Control and Standardization of Anti- 

 biotics 



Those antibiotics that have found prac- 

 tical application in disease control, in animal 

 feeding, or in the preservation of food mate- 

 rials are carefully controlled by official 

 government agencies in different countries 



(Dony and Guisset, 19G0). Official standards 

 are usually established for such antibiotics, 

 their sale for medicinal purposes being 

 limited primarily to prescriptions. The wide 

 and often indiscriminate use of antibiotics, 

 by many physicians and especially in certain 

 countries, has resulted in the rapid develop- 

 ment of resistance to antibiotics in general 

 and to some antibiotics, such as penicillin, 

 in particular. This has led to recommenda- 

 tions that a careful study be made of the 

 sensitivity of the causative agents of infec- 

 tion to various antibiotics, so that only a 

 specific antibiotic would always be em- 

 ployed. Finally, the World Health Organiza- 

 tion, recognizing the growing importance of 

 antibiotics in the world at large, has taken 

 steps to coordinate research in certain im- 

 portant problems pertaining to the wide use 

 of antibiotics. Its Expert Committee on 

 Antibiotics has recently (H)()f) published a 

 report on standardization uK^hods for assay- 

 ins; antibiotics. 



