632â1723Anthonie van Leeuwenhoek (1632-1723). Natuurkundige te Delft Rijksmuseum Antonie van LeeuwenhoekDutchConsidered to be the first acknowledged microscopist. Van Leeuwenhoek was the first to observe microscopic organisms, using simple single-lensed microscopes of his own design.[1]
1729â1799 Lazzaro SpallanzaniItalianProved that bacteria did not arise due to spontaneous generation by developing a sealed, sterile broth medium.[2][3]
1749â1823Edward Jenner  Edward JennerEnglishDeveloped vaccination techniques against smallpox.[2]
1818â1865Ignaz SemmelweisIgnaz SemmelweisHungarianDemonstrated that doctors washing their hands with chlorine solutoin significantly reduced mortality of women giving birth in the hospital setting.[4]
1853â1938Hans Christian Gram portrait  Hans Christian GramDanishDeveloped the Gram stain used to identify and classify bacteria.[2]
1845â1922Charles LaveranCharles LavaranFrench1907 Nobel Prize in Physiology or Medicine for discovering the causative agents of malaria and trypanosomiasis.[2]
1827â1912Joseph Lister  Joseph ListerEnglishIntroduced sterilisation techniques to surgery.[2][5]
1822â1895Louis Pasteur, foto av Paul Nadar, Crisco  Louis PasteurFrenchSeminal discoveries in vaccination, food safety, and microbial fermentatoion. A key proponent of the germ theory of disease.[2]
1850â1934Fanny HesseGermanDeveloped agar for use in culturing bacteria.[2][6]
1851â1934 Martinus BeijerinckNetherlandsDiscovered the first virus as well as bacterial nitrogen fixation and sulfate reduction.
1885â1948 Â Marjory StephensonBritishPioneer of bacterial metabolism.
1871â1957Kiyoshi ShigaJapaneseDiscovered a bacterium causing an outbreak of dysentery.[2][7]
1854â1917Emil Adolf von BehringGerman1901 Nobel Prize for Physiology or Medicine for discovering diphtheria antitoxin.[8]
1857â1932Sir Ronald RossBritish1902 Nobel Prize in Physiology or Medicine for discovering that malaria is transmitted by mosquitoes[9]
1843â1910Robert KochGerman1905 Nobel Prize in Physiology or Medicine for work on tuberculosis; identified causative agents of tuberculosis, cholera, and anthrax.[10]
1845â1922 Â Charles Louis Alphonse LaveranFrench1907 Nobel Prize in Physiology or Medicine for recognizing parasitic protozoa as the causes of malaria and African sleeping sickness.[11]
1857â1940 Â Julius Wagner-JaureggAustrian1927 Nobel Prize in Physiology or Medicine for discovering the neurosyphilis could be treated by inducing fever with malaria parasites.[12]
1866â1936 Â Charles Jules Henri NicolleFrench1928 Nobel Prize in Physiology or Medicine for determining that typhus is transmitted by body lice.[13]
1895â1964 Â Gerhard DomagkGerman1939 Nobel Prize in Physiology or Medicine for the discovering the first commercially available antibiotic: prontosil.[14]
1881â1955 Â Sir Alexander FlemingScottish1945 Nobel Prize in Physiology or Medicine for discovering penicillin.[15]
1906â1979 Â Sir Ernst Boris ChainBritish
1898â1968Howard Walter FloreyAustralian
1899â1972Max TheilerSouth African1951 Nobel Prize in Physiology or Medicine for developing a vaccine against yellow fever.[16]
1888â1973Selman Abraham WaksmanAmerican1952 Nobel Prize in Physiology or Medicine for identifying streptomycin and other antibiotics.[17]
(I really hope this helps you out!)