The first useful antibiotic found by screening was streptomycin. The late Prof. WAKSMAN started screening for antibacterial antibiotics in 1940 and, after finding actinomycin in 1941, he and his collaborators discovered streptomycin in 1944. This antibiotic made a great contribution in saving human lives from tuberculosis and acute serious infections. About 1957, after wide usage of such antibiotics as penicillin, streptomycin, chloramphenicol, tetracycline, and erythromycin, staphy- lococci and Gram negative organisms resistant to all or most antibiotic drugs ap- peared in hospital patients....