Microbiological Evaluation of certain compounds Derived from some Antibiotics

In this work, the antimicrobial properties of some new antibiotic derivatives were evaluated. Those antibiotic derivatives belong to the group of amine salts of penicillins and 6- amino penlcillanic acid. The penicillins whose amine salts were tested, are :benzylpenieillin ( pen. G) , phenox methylpenicillin ( pen .V) and ampicillin .The amine salts used are: 1- amine pen. G, 1- amine pen. V, 1- amine ampicillin , 1- amine 6- APA, reduced 1- amine pen. G, thiodiol pen, G, thiodiol pen V., clemipen and clemipen strep.For each of these amine salta -as well as for the parent ant¬ibiotic - the following was determined :a) The spectrum of activity against Gram, positive and Gram . negative microorganisms by the-agar dilution method.b) The minimum Inhibitory Concentration .against certain test microorganisms by the broth dilution methodc) The combined .antibacterial activity by gradient conce¬ntration technique and the agar diffusion .method,d) The effect of pH changes on the antimicrobial activity.e) The stability to gastric acidity.f) The stability to penicillinase enzyme.