Alexander Fleming was a Scottish microbiologist and physician. He is credited with discovering penicillin, the world's first effective antibiotic substance; a discovery that changed the course of history. He also discovered lysozyme, an antimicrobial enzyme which forms part of the innate immune system. In 1999, Fleming was named in Time magazine's 100 Most Important People of the 20th century list.
Robert Koch was a German microbiologist and physician. One of the prominent co-founders of modern bacteriology, Koch is credited with creating and improving laboratory techniques and technologies in the field of microbiology. He is also credited with making important discoveries in public health. In 1905, Robert Koch won the Nobel Prize in Physiology or Medicine for his research on tuberculosis.
Alexandre Yersin was a physician and bacteriologist. He is credited with co-discovering Yersinia pestis, the bacillus that causes the bubonic plague. Also an agriculturist, Yersin pioneered the cultivation of rubber trees. He is revered by the Vietnamese people because of his association with Hanoi Medical University; a private university in Da Lat is named in his honor.