Which antibiotic was discovered by Alexander Fleming in 1928?

The discovery of penicillin by Alexander Fleming in 1928 marked a significant breakthrough in medical science and antibiotic therapy. Fleming's observation of the mold Penicillium notatum inhibiting the growth of bacteria led to the development of penicillin, which became the first widely used antibiotic. This discovery revolutionized the treatment of bacterial infections, saving countless lives and paving the way for further research and development of other antibiotics.

Streptomycin, amoxicillin, and tetracycline were discovered later, building upon the groundwork that penicillin established. Streptomycin was discovered in the late 1940s and was one of the first antibiotics effective against tuberculosis. Amoxicillin, a derivative of penicillin, was developed in the 1970s to improve upon penicillin's efficacy and spectrum of activity. Tetracycline was discovered in the 1940s as well, known for its broad spectrum of activity and use against a variety of infections. Thus, penicillin holds a unique place in medical history as the first antibiotic discovered, directly attributable to Fleming's work.