Editing Bacteriology (section)

== History ==
{{for multi|the history of microbiology|Microbiology|the history of bacterial classification|Monera#History|and|Bacterial taxonomy|the natural history of Bacteria|Last universal common ancestor}}
[[File:Anthonie van Leeuwenhoek (1632-1723). Natuurkundige te Delft Rijksmuseum SK-A-957.jpeg|thumb|alt=painting of Antonie van Leeuwenhoek, in robe and frilled shirt, with ink pen and paper|[[Antonie van Leeuwenhoek]], the first person to observe bacteria using a [[microscope]].|left]]
[[File:Albert Edelfelt - Louis Pasteur - 1885.jpg|thumb|''Louis Pasteur in his laboratory'', painting by [[Albert Edelfelt|A. Edelfeldt]] in 1885]]
[[File:Statue of Robert Koch in Berlin.jpg|thumb|Statue of [[Robert Koch]] in Berlin]]

Bacteria were first observed by the Dutch microscopist [[Antonie van Leeuwenhoek]] in 1676, using a single-lens [[microscope]] of his own design. Leeuwenhoek did not recognize bacteria as a distinct category of microorganisms, and referred to all microorganisms, including bacteria, [[protists]], and microscopic animals, as [[animalcules]]. He published his observations in a series of letters to the [[Royal Society of London]]. His observations also included protozoans. The German [[Ferdinand Cohn]] began studying bacteria in 1870 and is also said to be a founder of bacteriology, as he was the first to classify bacteria into groups based on their [[Bacterial morphology|cell shapes]]. He defined bacteria as "chlorophyll-free cells of spherical, oblong, or cylindrical form, sometimes twisted or bent, which multiply exclusively by transverse division and occur either isolated or in cell families," and placed them in the plant kingdom. He also discovered heat-resistant bacterial [[endospores]]<ref name="Chung">{{cite web |last=Chung |first=King-Thom |name-list-style=vanc |title=Ferdinand Julius Cohn (1828–1898): Pioneer of Bacteriology |url=http://www.pnf.org/compendium/Ferdinand_Julius_Cohn.pdf |url-status=live |archive-url=https://web.archive.org/web/20110727180844/http://www.pnf.org/compendium/Ferdinand_Julius_Cohn.pdf |archive-date=27 July 2011 |publisher=Department of Microbiology and Molecular Cell Sciences, The University of Memphis |df=dmy-all}}</ref><ref name="microbeworld1">{{cite journal |author=Drews, Gerhart |year=1999 |title=Ferdinand Cohn, a founder of modern microbiology |url=http://www.microbeworld.org/images/stories/history_pdfs/f3.pdf |url-status=dead |journal=ASM News |volume=65 |issue=8 |pages=547–52 |archive-url=https://web.archive.org/web/20170713150622/http://www.microbeworld.org/images/stories/history_pdfs/f3.pdf |archive-date=13 July 2017}}</ref>

[[Louis Pasteur]] demonstrated in 1859 that microorganisms cause the [[fermentation (food)|fermentation]] process, and that this growth is not due to [[spontaneous generation]] ([[yeast]]s and [[Mold (fungus)|molds]], commonly associated with fermentation, are not bacteria, but rather [[fungus|fungi]]). Along with his contemporary [[Robert Koch]], Pasteur was an early advocate of the [[germ theory of disease]].<ref>{{cite web|url = http://biotech.law.lsu.edu/cphl/history/articles/pasteur.htm#paperII|title = Pasteur's Papers on the Germ Theory|publisher = LSU Law Center's Medical and Public Health Law Site, Historic Public Health Articles|access-date = 23 November 2006| archive-url= https://web.archive.org/web/20061218123426/http://biotech.law.lsu.edu/cphl/history/articles/pasteur.htm| archive-date= 18 December 2006 | url-status= live}}</ref> Between 1880 and 1881 Pasteur produced two successful [[vaccination]]s for animals against diseases caused by bacteria. The importance of bacteria was recognized as it led to a study of disease prevention and treatment of diseases by vaccines.<ref name="Kreuder-Sonnen" /><ref name="Baron" /> Pasteur's research led to [[Ignaz Semmelweis]] and [[Joseph Lister]] researching the importance of sanitized hands in medical work.

In the 1840s, Semmelweis' observations and ideas surrounding sanitary techniques were rejected and his book on the topic condemned by the medical community due to its conflict with the prevailing theory and practice of [[humorism]] at the time.<ref>{{Cite book |last=Carter |first=K. Codell |url=https://www.worldcat.org/oclc/56198835 |title=Childbed fever : a scientific biography of Ignaz Semmelweis, with a new introduction by the authors |date=2005 |publisher=Transaction Publishers |others=Barbara R. Carter |isbn=1-4128-0467-1 |location=New Brunswick, N.J. |oclc=56198835}}</ref> After Lister's publications, which supported hand washing and sanitation with germ theory, doctors started sanitizing their hands in the 1870s; mandatory handwashing was not incorporated into common health practice until as late as the 1980s.<ref>''[https://web.archive.org/web/20210224040602/https://www.nationalgeographic.com/history/article/handwashing-once-controversial-medical-advice 'Wash your hands' was once controversial medical advice]'', National Geographic.</ref>

The discovery of the connection of microorganisms to disease came later in the nineteenth century, when Italian anatomist [[Filippo Pacini]] isolated the [[cholera]] bacterium ''[[Vibrio cholerae]]'' in 1854 in Florence during the Asiatic Cholera Pandemic of 1846–63<ref>{{Cite journal |last=Pacini |first=Filippo |date=1854 |title=Osservazioni microscopiche e deduzioni patologiche sul cholera asiatico (Microscopic observations and pathological deductions on Asiatic cholera) |url=https://books.google.com/books?id=F9s_AAAAcAAJ&pg=PA1 |journal=Gazzetta Medica Italiana: Toscana |volume=4 |issue=50; 51 |pages=397–401; 405–412}}</ref> and clearly linked the presence of the bacterium in the intestinal mucosa of dead cholera patients to the disease.
Although Pacini's work was available to the international scientific community via French and English translations, the discovery of the cholera-causing agent is often attributed to the German physician [[Robert Koch]] who rediscovered it in 1884. Koch is credited for introducing the science of microorganisms including bacteria to the medical field.<ref>{{cite journal |last=Lakhtakia |first=R. |title=The Legacy of Robert Koch |journal=Sultan Qaboos University Medical Journal |date=February 2014 |volume=14 |issue=1 |pages=e37–41 |doi=10.12816/0003334 |pmid=24516751 |pmc=3916274}}</ref> Koch, a pioneer in medical microbiology, worked on [[cholera]], [[anthrax]] and [[tuberculosis]]. In his research into tuberculosis Koch finally proved the germ theory, for which he received a [[Nobel Prize in Physiology or Medicine|Nobel Prize]] in 1905.<ref name=":0">{{cite web |title=The Nobel Prize in Physiology or Medicine 1905 |url=http://nobelprize.org/nobel_prizes/medicine/laureates/1905/ |url-status=live |archive-url=https://web.archive.org/web/20061210184150/http://nobelprize.org/nobel_prizes/medicine/laureates/1905/ |archive-date=10 December 2006 |access-date=22 November 2006 |publisher=Nobelprize.org}}</ref> In [[Koch's postulates]], he set out criteria to test if an organism is the cause of a [[disease]], and these postulates are still used today.<ref>{{cite journal |vauthors=O'Brien SJ, Goedert JJ |date=October 1996 |title=HIV causes AIDS: Koch's postulates fulfilled |url=https://zenodo.org/record/1260157 |journal=Current Opinion in Immunology |volume=8 |issue=5 |pages=613–18 |doi=10.1016/S0952-7915(96)80075-6 |pmid=8902385}}</ref><ref name="Kreuder-Sonnen" /> Both Koch and Pasteur played a role in improving antisepsis in medical treatment. In 1870–1885 the modern methods of bacteriology technique were introduced by the use of [[Staining|stains]], and by the method of separating mixtures of organisms on plates of nutrient media.<ref name="Kreuder-Sonnen" /><ref name="Baron" />

Though it had been known since the nineteenth century that bacteria are a cause of many diseases, no effective [[antiseptic|antibacterial]] treatments were available until the 20th century.<ref>{{cite journal | vauthors = Thurston AJ | title = Of blood, inflammation and gunshot wounds: the history of the control of sepsis | journal = The Australian and New Zealand Journal of Surgery | volume = 70 | issue = 12 | pages = 855–61 | date = December 2000 | pmid = 11167573 | doi = 10.1046/j.1440-1622.2000.01983.x | doi-access = free }}</ref> In 1910, [[Paul Ehrlich]] developed the first antibiotic, by changing dyes that selectively stained ''[[Treponema pallidum]]''—the [[spirochaete]] that causes [[syphilis]]—into compounds that selectively killed the pathogen.<ref>{{cite journal | vauthors = Schwartz RS | title = Paul Ehrlich's magic bullets | journal = The New England Journal of Medicine | volume = 350 | issue = 11 | pages = 1079–80 | date = March 2004 | pmid = 15014180 | doi = 10.1056/NEJMp048021 }}</ref> Ehrlich was awarded a 1908 Nobel Prize for his work on [[immunology]], and pioneered the use of stains to detect and identify bacteria, with his work being the basis of the [[Gram stain]] and the [[Ziehl–Neelsen stain]].<ref>{{cite web|url = http://nobelprize.org/nobel_prizes/medicine/laureates/1908/ehrlich-bio.html|title = Biography of Paul Ehrlich|publisher = Nobelprize.org|access-date = 26 November 2006| archive-url= https://web.archive.org/web/20061128093700/http://nobelprize.org/nobel_prizes/medicine/laureates/1908/ehrlich-bio.html| archive-date= 28 November 2006 | url-status= live}}</ref>

In the early 20th century, there was debate about the classification of bacteria. In 1904, cyanobacteria were usually classified as a class of algae, which are eukaryotic. However, Haeckel at this time classed cyanobacteria with bacteria because they lacked nuclei. In 1938, Herbert Faulkner Copeland proposed that prokaryotes be granted their own kingdom. The development of the [[transmission electron microscope]] allowed better visualization of cell structure and helped to clarify issues. In 1962, Stanier and van Niel<ref>https://link-springer-com.wikipedialibrary.idm.oclc.org/content/pdf/10.1007/BF00425185.pdf</ref> published an influential definition of bacteria, proposing that bacteria be defined as prokaryotic cellular entities; they also specified three differences between prokaryotes and eukaryotes: presence or absence of internal membranes, division by fission or mitosis, and presence or absence of a cell wall.<ref>https://pmc.ncbi.nlm.nih.gov/articles/PMC1197417</ref>

A major step forward in the study of bacteria came in 1977 when [[Carl Woese]] recognised that [[archaea]] have a separate line of evolutionary descent from bacteria.<ref name=Woese1977>{{cite journal | vauthors = Woese CR, Fox GE | title = Phylogenetic structure of the prokaryotic domain: the primary kingdoms | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 74 | issue = 11 | pages = 5088–90 | date = November 1977 | pmid = 270744 | pmc = 432104 | doi = 10.1073/pnas.74.11.5088 | bibcode = 1977PNAS...74.5088W | doi-access = free }}</ref> This new [[phylogenetic]] [[Taxonomy (biology)|taxonomy]] came from the [[sequencing]] of [[16S ribosomal RNA]] and divided prokaryotes into two evolutionary domains as part of the [[three-domain system]].<ref>{{cite book |vauthors=Hall B |title=Strickberger's Evolution : the integration of genes, organisms and populations |publisher=Jones and Bartlett |publication-place=Sudbury, Mass |year=2008 |isbn=978-0-7637-0066-9 |oclc=85814089 |page=145}}</ref>