Bacteriology

Bacteria Vibrio vulnificus.

Bacteriology is the branch and specialty of biology that studies the morphology, ecology, ethology, genetics and biochemistry of prokaryotes (bacteria and archaea) as well as many other aspects related to them.

This discipline of microbiology involves the identification, classification, and characterization of bacterial and archaeal species. Due to the similarity of thinking and working with microorganisms other than prokaryotes such as protozoa, algae, and unicellular fungi, there has been a tendency for the field of bacteriology to be extended as simply microbiology. The terms were previously used interchangeably. However, bacteriology can be classified as a distinct science or as a discipline within microbiology.

The study of bacteriology comprises two totally different domains of life, Bacteria and Archaea, which share the presence of prokaryotic cells. Archaea were previously considered bacteria and were called 'archaebacteria', but later molecular analyzes revealed that archaea constitute a separate domain, closely related to eukaryotes and also related to their origin.

Introduction

Bacteriology is the study of prokaryotes and their relationship to medicine and industry. Bacteriology evolved from physicians needing to apply germ theory to assess concerns related to spoilage of food and wine in the XIX. The identification and characterization of disease-associated bacteria led to advances in pathogenic bacteriology. Koch's postulates played an important role in identifying relationships between bacteria and specific diseases. Since then, bacteriology has had many successful advances as 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 the typhoid vaccine. Bacteriology has also provided the discovery of antibiotics.

History of bacteriology

Anton van Leeuwenhoek, the first person who observed a bacterium through a microscope.

The existence of microorganisms was conjectured in the late Middle Ages. In the Canon of Medicine (1020), Abū Alī ibn Sīnā (Avicenna) stated that bodily secretions were contaminated by multiple infectious foreign bodies before a person fell ill., but he did not go so far as to identify these bodies as the first cause of the diseases. When the Black Death (bubonic plague) reached al-Andalus in the XIV century, Ibn Khatima and Ibn al-Khatib wrote that infectious diseases were caused by contagious entities penetrating the human body. These ideas about contagion as the cause of some diseases became very popular during the Renaissance, notably through the writings of Girolamo Fracastoro.

The first bacteria were observed by the Dutchman Anton van Leeuwenhoek in 1676 using a single-lens microscope designed by himself. He initially called them animalcules and published his observations in a series of letters he sent to to the Royal Society of London. The Viennese physician Marcus von Plenciz (1705-1786) claimed that contagious diseases were caused by the small organisms discovered by Leeuwenhoek. The name bacteria was introduced later, in 1828, by Christian Gottfried Ehrenberg, and derives from the Greek βακτήριον bacterion, meaning little stick. In 1835 Agostino Bassi was able to experimentally demonstrate that the silkworm disease was of microbial origin, and later deduced that many other diseases such as typhus, syphilis and cholera had a similar origin. In the classifications of the 1850s they were still considered "animalcules".

The field of bacteriology (later a subdiscipline of microbiology) was founded by Ferdinand Cohn (1828-1898), a German botanist whose studies of algae and photosynthetic bacteria led him to describe many bacteria, some already discovered, such as Bacillus and Beggiatoa and others discovered by him, such as Crenothrix polyspora. Cohn was the first to formulate a scheme for the taxonomic classification of bacteria, in Untersuchungen über Bacterien [Studies on Bacteria, 1872] and Neue Untersuchungen über Bakterien [New Studies on bacteria, Bonn, 1872-1875] and in discovering endospores. Cohn placed bacteria in the plant kingdom and in 1875 named them Schizophyta, dividing them into two groups: Schizophyceae (from schizo=partition, phyceae=alga) or blue-green algae (modern cyanobacteria) and Schizomycetes or Schizomyceae (from schizo=partition, myco=fungus).

Louis Pasteur in your lab (1885). The innovative laboratory crystalry and experimental methods developed by Louis Pasteur and other biologists contributed to the young field of bacteriology at the end of the centuryXIX.

Louis Pasteur and Robert Koch were contemporaries of Cohn, and are often regarded as the fathers of microbiology and medical microbiology, respectively. Pasteur demonstrated in 1859—in a series of well-known experiments designed to refute the then well-established theory of spontaneous generation—that fermentation processes were caused by the growth of microorganisms. He thus consolidated microbiology as a biological science (neither yeasts, nor molds, nor fungi, organisms normally associated with these fermentation processes, are bacteria). The discovery of the connection of microorganisms with diseases is due to the German doctor Koch, who introduced the science of microorganisms in the field of medicine. He identified bacteria as the cause of infectious diseases—such as cholera, anthrax, and tuberculosis—and of the fermentation process in diseases, proving that specific diseases were caused by specific pathogenic microorganisms. Koch helped prove the microbial theory of disease by being one of the first scientists to focus on the isolation of bacteria in pure culture, which led to the description of several novel bacteria, including Mycobacterium tuberculosis, the causative agent of tuberculosis. He was awarded the Nobel Prize in Medicine and Physiology for this in 1905. He established what have since been called Koch's postulates, a series of experimental criteria to prove whether or not an organism was the cause of a certain disease. These postulates continue to be used today. Both Koch and Pasteur played a role in improving antisepsis in medical treatment—with a huge positive effect on public health and a better understanding of the body and disease—and recognized the importance of antisepsis. importance of bacteria, which led to a study on the prevention and treatment of disease through vaccines. Pasteur himself discovered vaccines against various bacterial diseases such as anthrax, fowl cholera and rabies and also developed methods for food preservation (pasteurization). One of Pasteur's students, Adrien Certes, is considered the founder of marine microbiology.

In 1870-1885 modern methods of bacteriology technique were introduced through the use of stains and the method of separating mixtures of organisms on plates of nutrient media. Although at the end of the XIX century it was already known that bacteria were the cause of a multitude of diseases, there were no antibacterial treatments to combat them. In 1882 Paul Ehrlich, a pioneer in the use of stains and dyes to detect and identify bacteria, discovered the stain for Koch's bacillus (Ziehl Neelsen stain) which was soon after perfected by Ziehl and Neelsen independently. In 1884 the Gram stain. Ehrlich received the Nobel Prize in 1908 for his work in the field of immunology and in 1910 developed the first antibiotic using dyes capable of selectively staining and killing spirochetes of the species Treponema pallidum, the bacterium that causes syphilis.

However, the work of Pasteur and Koch often did not accurately reflect the true diversity of the microbial world due to their exclusive focus on microorganisms of direct medical relevance. Until the end of the XIX century, with the works of Martinus Beijerinck (1851-1931) and Sergei Vinogradsky (1856-1953), the true breadth of microbiology was not revealed. Beijerinck made two major contributions to microbiology: the discovery of viruses and the development of enrichment culture techniques. While his work on tobacco mosaic virus established the basic principles of virology, it was his development of the culture of enrichment that had the most immediate impact on microbiology by allowing the cultivation of a wide range of microbes with very different physiologies. Vinogradski was the first to develop the concept of chemolithotrophy, thus revealing the essential role played by microorganisms in geochemical processes. He was responsible for the first isolation and description of nitrifying bacteria and nitrogen-fixing bacteria. French-Canadian microbiologist Felix d'Herelle co-discovered bacteriophages in 1917 and was one of the first applied microbiologists.

A breakthrough in the study of bacteria was the discovery by Carl Woese in 1977 that archaea have a different evolutionary lineage than bacteria. This new phylogenetic taxonomy was based on ribosomal RNA sequencing 16S and divided prokaryotes into two different evolutionary groups, in a system of three domains: Archaea, Bacteria, and Eukarya.

Medically Important Bacteria Discoveries (First Descriptions)

• 1873: Mycobacterium leprae by Gerhard Armauer Hansen
• 1875: Clostridium chauvoei (Syn. C. feseri) by Johann Feser
• 1876: Bacillus anthracis by Robert Koch
• 1877: Clostridium septicum by Louis Pasteur, Jules Joubert
• 1879: Neisseria gonorrhoeae by Albert Neisser
• 1880: Salmonella typhi by Karl Joseph Eberth

Erysipelothrix muriseptica by Robert Koch

• 1882: Mycobacterium tuberculosis by Robert Koch

Burkholderia mallei (Syn. Malleomyces m.) by Friedrich Loeffler and Wilhelm Schütz

Streptococcus pyogenes by Friedrich Fehleisen

• 1883: Vibrio cholerae by Robert Koch

Corynebacterium xerosis by Albert Neisser and S. Kuschbert

• 1884: Corynebacterium diphtheriae by F. Loeffler

Clostridium tetani by Arthur Nicolaier

• 1885: Mycobacterium smegmatis by E. Alvarez and Ernst Tavel,

Salmonella choleraesuis by Daniel Elmer Salmon

Corynebacterium pseudotuberculosis by Edmond Nocard

• 1886: Streptococcus pneumoniae (Syn. Diplococcus p.) by Albert Fraenkel (Mediziner, 1848) and Anton Weichselbaum

Erysipelothrix rhusiopathiae by Friedrich Loeffler

• 1887: Neisseria meningitidis by Anton Weichselbaum

Corynebacterium pseudodiphthericum by Franz Adolf Hofmann

Streptococcus agalactiae by E. Nocard and Hyacinthe Mollereau

• 1888: Salmonella enteritidis by August Gärtner
• 1891: Salmonella typhimurium by Friedrich Loeffler
• 1892: Micrococcus epidermidis by William Henry Welch

Moraxella catarrhalis (Syn. Branhamella catarrhalis, Neisseria v.) by Seifert and Richard Pfeiffer

Clostridium perfringens by William Henry Welch and George Nuttal

• 1893: Arcanobacterium pyogenes by Adrien Lucet
• 1894: Clostridium novyi by Frederick G. Novy
• 1896: Mycobacterium bovis by Theobald Smith

Clostridium botulinum durch Emile van Ermengem

• 1897: Propionibacterium acnes (Syn. Corynebacterium acnes) by Raymond Sabouraud
• 1898: Shigella dysenteriae by Kiyoshi Shiga

Mycoplasma by E. Nocard, Émile Roux

• 1900: Salmonella paratyphi B by Hugo Schottmüller

Shigella flexneri (Syn. S. paradysenteriae B) by Simon Flexner and Richard Pearson Strong

Shigella boydii by Mark Frederick Boyd

• 1903: Enterococcus faecalis (Syn. Streptococcus f.) by Theodor Escherich
• 1905: Treponema pallidum by Fritz Schaudinn, Erich Hoffmann

Treponema pertenue durch Aldo Castellani

• 1907: Shigella sonnei D by Walter Kruse, Carl Olaf Sonne

Chlamydia trachomatis by Ludwig Halberstaedter and Stanislaus von Prowazek

• 1910: Micrococcus denitrificans by Martinus Beijerinck
• 1983: Helicobacter pylori by Barry Marshall and John Robin Warren