Bacteriology

Bacteriology is the study of bacteria and their relation to medicine. Bacteriology evolved from physicians needing to apply the germ theory to test the concerns relating to the spoilage of foods and wines in the 19th century. Identification and characterizing of bacteria being associated to diseases led to advances in pathogenic bacteriology. Koch's postulates played a role into identifying the relationships between bacteria and specific diseases. Since then, bacteriology has had many successful advances like effective vaccines, for example, diphtheria toxoid and tetanus toxoid. There have also been some vaccines that were not as effective and have side effects for example, typhoid vaccine. Bacteriology has also provided discovery of antibiotics.

Antonie van Leeuwenhoek, the first microbiologist and the first person to observe bacteria using a microscope.

Louis Pasteur in his laboratory, painting by A. Edelfeldt in 1885

Statue of 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. He then published his observations in a series of letters to the Royal Society of London.[6] His observations had also included protozoans which he called animalcules.[7]

Christian Gottfried Ehrenberg introduced the word "bacterium" in 1828.[8] In fact, his Bacterium was a genus that contained non-spore-forming rod-shaped bacteria,[9] as opposed to Bacillus, a genus of spore-forming rod-shaped bacteria defined by Ehrenberg in 1835.[10]

Louis Pasteur demonstrated in 1859 that the growth of microorganisms causes the fermentation process, and that this growth is not due to spontaneous generation (yeasts and molds, commonly associated with fermentation, are not bacteria, but rather fungi). Along with his contemporary Robert Koch, Pasteur was an early advocate of the germ theory of disease.[11] Before them, Ignaz Semmelweis and Joseph Lister had realised the importance of sanitized hands in medical work. Semmelweis' ideas were rejected and his book on the topic condemned by the medical community, but after Lister doctors started sanitizing their hands in the 1870s. While Semmelweis who started with rules about handwashing in his hospital in the 1840s predated the spread of the ideas about germs themselves and attributed diseases to "decomposing animal organic matter", Lister was active later.[12]

The discovery of the connection of microorganisms to disease can be dated back to the nineteenth century, when German physician Robert Koch introduced the science of microorganisms to the medical field.[13] He identified bacteria as the cause of infectious diseases and process of fermentation in diseases.[14][15][16] 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 1905.[17] 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.[18] Louis Pasteur developed techniques to produce vaccines. Both Koch and Pasteur played a role in improving antisepsis in medical treatment. This had an enormous positive effect on public health and gave a better understanding of the body and diseases. In 1870-1885 the modern methods of bacteriology technique were introduced by the use of stains and by the method of separating mixtures of organisms on plates of nutrient media. Between 1880 and 1881 Pasteur produced two successful vaccinations for animals against diseases caused by bacteria and it was successful. The importance of bacteria was recognized as it led to a study of disease prevention and treatment of diseases by vaccines.[14][15][16]

Ferdinand Cohn is said to be a founder of bacteriology, studying bacteria from 1870. Cohn was the first to classify bacteria based on their morphology.[19][20]

Though it was known in the nineteenth century that bacteria are the cause of many diseases, no effective antibacterial treatments were available.[21] 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.[22] Ehrlich had been 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.[23]

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.[24] This new phylogenetic taxonomy depended on the sequencing of 16S ribosomal RNA, and divided prokaryotes into two evolutionary domains, as part of the three-domain system.[25] Bacteriology has developed and can be studied in agriculture, marine biology, water pollution, bacterial genetics and biotechnology.[14][15][16]

• Bacterial phylodynamics, the study of immunology, epidemiology, and phylogenetics of bacterial pathogens to better understand the evolutionary role of these pathogens

• Hall, Brian (2008). Strickberger's Evolution : the integration of genes, organisms and populations. Sudbury, Mass: Jones and Bartlett. ISBN 978-0-7637-0066-9. OCLC 85814089.
• Pommerville JC (2014). Fundamentals of Microbiology (10th ed.). Boston: Jones and Bartlett. ISBN 978-1-284-03968-9.
• Wheelis, Mark (2008). Principles of modern microbiology. Sudbury, Mass: Jones and Bartlett Publishers. ISBN 978-0-7637-1075-0. OCLC 67392796.

• McGrew, Roderick, ed. (1985). "brief history". Encyclopedia of Medical History. McGraw-Hill. pp. 25–30. ISBN 0070450870.