Robert Koch
Heinrich Hermann Robert Koch was a German physician and microbiologist. He won the 1905 Nobel Prize in Physiology or Medicine "for his investigations and discoveries in relation to tuberculosis".
As the discoverer of the specific causative agents of deadly infectious diseases including tuberculosis, cholera and anthrax, he is regarded as one of the main founders of modern bacteriology. As such he is popularly nicknamed the father of microbiology, and as the father of medical bacteriology. His discovery of the anthrax bacterium in 1876 is considered as the birth of modern bacteriology. Koch used his discoveries to establish that germs "could cause a specific disease" and directly provided proofs for the germ theory of diseases, therefore creating the scientific basis of public health, saving millions of lives. For his life's work Koch is seen as one of the founders of modern medicine.
While working as a private physician, Koch developed many innovative techniques in microbiology. He was the first to use the oil immersion lens, condenser, and microphotography in microscopy. His invention of the bacterial culture method using agar and glass plates made him the first to grow bacteria in the laboratory. In appreciation of his work, he was appointed to government advisor at the Imperial Health Office in 1880, promoted to a senior executive position in 1882, Director of Hygienic Institute and Chair of the Faculty of Medicine at Berlin University in 1885, and the Royal Prussian Institute for Infectious Diseases in 1891.
The methods Koch used in bacteriology led to the establishment of a medical concept known as Koch's postulates, four generalized medical principles to ascertain the relationship of pathogens with specific diseases. The concept is still in use in most situations and influences subsequent epidemiological principles such as the Bradford Hill criteria. A major controversy followed when Koch discovered tuberculin as a medication for tuberculosis which was proven to be ineffective, but developed for diagnosis of tuberculosis after his death. The day he announced the discovery of the tuberculosis bacterium, 24 March 1882, has been observed by the World Health Organization as "World Tuberculosis Day" every year since 1982.
Early life and education
Koch was born in Clausthal, Germany, on 11 December 1843, to Hermann Koch and Mathilde Julie Henriette. His father was a mining engineer. He was the third of thirteen siblings. He excelled academically from an early age. Before entering school in 1848, he had taught himself how to read and write. He completed secondary education in 1862, having excelled in science and math.At the age of 19, in 1862, Koch entered the University of Göttingen to study natural science. He took up mathematics, physics and botany. He was appointed assistant in the university's Pathological Museum. After three semesters, he decided to change his area of study to medicine, as he aspired to be a physician. During his fifth semester at the medical school, Jacob Henle, an anatomist who had published a theory of contagion in 1840, asked him to participate in his research project on uterine nerve structure. This research won him a research prize from the university and enabled him to briefly study under Rudolf Virchow, who was at the time considered "Germany's most renowned physician". In his sixth semester, Koch began to research at the Physiological Institute, where he studied the secretion of succinic acid, which is a signalling molecule that is also involved in the metabolism of the mitochondria. This would eventually form the basis of his dissertation. In January 1866, he graduated from the medical school, earning honours of the highest distinction, maxima cum laude.
Career
After graduation in 1866, Koch briefly worked as an assistant in the General Hospital of Hamburg. In October of that year, he moved to Idiot's Hospital of Langenhagen, near Hanover, as a junior physician. In 1868, he moved to Neimegk and then to Rakwitz in 1869. As the Franco-Prussian War started in 1870, he enlisted in the German army as a volunteer surgeon in 1871 to support the war effort. He was discharged a year later and was appointed as a district physician in Wollstein in Prussian Posen. As his family settled there, his wife gave him a microscope as a birthday gift. With the microscope, he set up a private laboratory and started his career in microbiology.Koch began conducting research on microorganisms in a laboratory connected to his patient's examination room. His early research in this laboratory yielded one of his major contributions to the field of microbiology, as he developed the technique of growing bacteria. Furthermore, he managed to isolate and grow selected pathogens in a pure laboratory culture. His discovery of the anthrax bacillus hugely impressed Ferdinand Julius Cohn, professor at the University of Breslau, who helped him publish the discovery in 1876. Cohn had established the Institute of Plant Physiology and invited Koch to demonstrate his new bacterium there in 1877. Koch was transferred to Breslau as district physician in 1879. A year after, he left for Berlin when he was appointed a government advisor at the Imperial Health Office, where he worked from 1880 to 1885. Following his discovery of the tuberculosis bacterium, he was promoted to Geheimer Regierungsrat, a senior executive position, in June 1882.
In 1885, Koch received two appointments as an administrator and professor at Berlin University. He became Director of Hygienic Institute and Chair of the Faculty of Medicine. In 1891, he relinquished his professorship and became a director of the Royal Prussian Institute for Infectious Diseases which consisted of a clinical division and beds for the division of clinical research. For this, he accepted harsh conditions. The Prussian Ministry of Health insisted after the 1890 scandal with tuberculin, which Koch had discovered and intended as a remedy for tuberculosis, that any of Koch's inventions would unconditionally belong to the government and he would not be compensated. Koch lost the right to apply for patent protection. In 1906, he moved to East Africa to research a cure for trypanosomiasis. He established the Bugula research camp where up to 1000 people a day were treated with the experimental drug Atoxyl.
Scientific contributions
Anthrax
Robert Koch is widely known for his work with anthrax, discovering the causative agent of the fatal disease to be Bacillus anthracis. After officially becoming a district physician in Wollstein, Poland, in 1872, Robert began to delve into the disease called Anthrax. Near Wollstein, anthrax disease was regularly taking the lives of humans and livestock without evidence explaining why. Eventually, in 1876, Koch was able to make an incredible discovery that anthrax was triggered by one singular pathogen. Koch's discovery of the dormant stage, the anthrax spores, allowed him to successfully unravel the mystery behind the anthrax disease. By gaining a better understanding of this pathogen, he was able to shed light on the bacterium's remarkable resistance to environmental factors. This groundbreaking achievement marked Koch as the pioneer scientist to discover that a microscopic organism was causing a disease to spread. His findings were especially impressive as they were done in a poorly equipped laboratory in Wollstein.He published the discovery in a booklet as "Die Ätiologie der Milzbrand-Krankheit, Begründet auf die Entwicklungsgeschichte des Bacillus Anthracis" in 1876 while working in Wollstein. His publication in 1877 on the structure of anthrax bacterium marked the first photography of a bacterium. He discovered the formation of spores in anthrax bacteria, which could remain dormant under specific conditions. However, under optimal conditions, the spores were activated and caused disease. To determine this causative agent, he dry-fixed bacterial cultures onto glass slides, used dyes to stain the cultures, and observed them through a microscope. His work with anthrax is notable in that he was the first to link a specific microorganism with a specific disease, rejecting the idea of spontaneous generation and supporting the germ theory of disease.
Techniques in bacteria study
Robert Koch made two important developments in microscopy; he was the first to use an oil immersion lens and a condenser that enabled smaller objects to be seen. In addition, he was also the first to effectively use photography for microscopic observation. He introduced the "bedrock methods" of bacterial staining using methylene blue and Bismarck brown dye. In an attempt to grow bacteria, Koch began to use solid nutrients such as potato slices. Through these initial experiments, Koch observed individual colonies of identical, pure cells. He found that potato slices were not suitable media for all organisms, and later began to use nutrient solutions with gelatin. However, he soon realized that gelatin, like potato slices, was not the optimal medium for bacterial growth, as it did not remain solid at 37 °C, the ideal temperature for growth of most human pathogens. Furthermore, many bacteria can hydrolyze gelatin, making it a liquid. As suggested to him by his post-doctoral assistant Walther Hesse, who got the idea from his wife Fanny Hesse, in 1881, Koch started using agar to grow and isolate pure cultures. Agar is a polysaccharide that remains solid at 37 °C, is not degraded by most bacteria, and results in a stable transparent medium.Development of Petri dish
Koch's booklet published in 1881 titled "Zur Untersuchung von pathogenen Organismen" has been known as the "Bible of Bacteriology." In it he described a novel method of using glass slide with agar to grow bacteria. The method involved pouring a liquid agar onto the glass slide and then spreading a thin layer of gelatin over it. The gelatin made the culture medium solidify, in which bacterial samples could be spread uniformly. The whole bacterial culture was then put on a glass plate together with a small wet paper. Koch named this container as feuchte Kammer. The typical chamber was a circular glass dish 20 cm in diameter and 5 cm in height and had a lid to prevent contamination. The glass plate and the transparent culture media made observation of the bacterial growth easy.Koch publicly demonstrated his plating method at the Seventh International Medical Congress in London in August 1881. There, Louis Pasteur exclaimed, "C'est un grand progrès, Monsieur!" It was using Koch's microscopy and agar-plate culture method that his students discovered new bacteria. Friedrich Loeffler discovered the bacteria of glanders in 1882 and diphtheria in 1884; and Georg Theodor August Gaffky, the bacterium of typhoid in 1884. Koch's assistant Julius Richard Petri developed an improved method and published it in 1887 as "Eine kleine Modification des Koch’schen Plattenverfahrens". The culture plate was given an eponymous name Petri dish. It is often asserted that Petri developed a new culture plate, but this was not so. He simply discarded the use of glass plate and instead used the circular glass dish directly, not just as a moist chamber, but as the main culture container. This further reduced the chances of contaminations. It would also have been appropriate if the name "Koch dish" had been given.