• Bacteriostatic are things that prevent the growth of bacteria. • Bactericidal-kills bacteria History of antimicrobial agents • Alexander Fleming- discovered penicillin released from penicillium. • Gerhard Domagk- discovered sulfanilamide. • Selman Waksman- antibiotics- antimicrobial agent produced naturally by organisms. Penicillium mould produces funguses penicillin which is ? Semi synthetics-chemically altered antibiotics are more effective, longer-lasting or easier to administer than naturally occurring.