Abstract
1) Antibacterial activity of 21 kinds of penicillin derivatives was tested against 18 kinds of bacterium. It was found that their activity fairly varied according to the kinds of bases used.
P-aminobenzaldehydethiosemicarbazone-Pc and dl-p-nitrophenyl-2-amino-1, 3-propanediol-Pc showed high antibacterial activity against gramnegative bacteria which had low sensitivity to penicillin and p-aminobenzaldehdethiosemicarbazone-Pc and p-aminosalicylicacid-Pc showed rather high antibacterial power against Myco. tuberculosis H 37 RV that was not so sensitive to penicillin.
2) Various kinds of salts obtained by making various organic bases react to penicillin showed the same grade of activity as procain-Pc against grampositive cocci sensitive to penicillin.
3) Pyrimidine-Pc showed much higher antibacterial activity than procain-Pc against Br. melitensis.
4) It was studied how the drug resistance of Staph. aureus 209 P and Terashima to various penicillin derivatives would develop. It was found that Staph. aureus 209 P and Terashima got resistance against metal (Na and Ca) salts of penicillin as well as against its organic salts. They got resistance more easily against the former.
Penicillin resistant variants of bacterium were likely to show rather poor growth in the culture media.
