The word “bacteriology” did not exist in the early 1880s. With people such as Louis Pasteur (France) and Robert Koch (Germany), a new field of study emerged. Between 1870 and 1890, many bacteria were discovered, described and given names. Robert Koch discovered the tuberculosis bacterium (Mycobacterium tuberculosis) and the cholera bacterium (Vibrio cholerae). The same applies to Escherichia coli, named after its discoverer Theodor Escherich (1857-1911). Bacteriology opened up a completely new window to observe the world and understand the spread of disease in a different way. It was important to realise that bacteria could form the basis for infections; bacteria thus proved to be (also) a potential pathogen.
Theodor Escherich (1857-1911)
Escherich was a paediatrician, bacteriologist and professor who discovered the bacterium in the human intestine and stool in 1885. He used his discovery for his thesis (Habilitation) in his research into the health of young children. The bacterium was so common in children and adults that Escherich named it Bacterium coli commune. After his death, the bacterium was renamed the well-known Escherichia coli, or E.coli for short. Paediatrician Escherich became famous in 1903 for his plea to feed babies mainly their own mother’s own (raw) milk. Driven by poverty, working mothers (labourers) were unable to feed their own children, and the wealthier classes often did not want to feed their own children. Theodor Escherich first worked at the pathological institute in Vienna and then researched breast milk. He was the first to demonstrate that breast milk sampled from the first day after birth up to 8 months was sterile, while the milk of feverish mothers contained yellow and white staphylococci (Friedman, 2006). Escherich was convinced that knowledge of bacteria could solve many problems in young children. As a paediatrician, Theodor Escherich took up the fight against diarrhoea in young children, a problem that, together with dehydration, could be fatal to them, especially in the summer. The world of bacteria was still largely unknown and certainly not recognised as the cause of diseases such as diarrhoea.
The knowledge gained in the early 1880s about cholera (in Naples) and E.coli in children prompted a shift in focus towards hygiene. Several universities established new chairs on the subject of “hygiene” and thus on prevention. This ultimately proved to be one of the most important contributions to the reduction of infectious diseases, long before antibiotics and penicillin came into use. Running water, flush toilets and separate sewage systems in cities, combined with improved nutrition, clean hands and clothing, and the pasteurisation of poor-quality milk, led to a significant decline in infant mortality.
E. coli as a model for understanding bacterial growth and infections
E.coli eventually became a kind of model bacterium. It was found everywhere and was easy to cultivate. Much of the biochemical and genetic knowledge we now have about micro-organisms started with the cultivation of E.coli. Escherich quickly realised that E.coli had strains of varying virulence, some responsible for the normal digestion of our food in the small intestine and others causing diarrhoea. In his day, Escherich mainly observed differences in the shapes and behaviour of the E.coli variants under the microscope. Thanks to molecular research over the last 30-40 years, researchers are now much better able to understand the multitude of strains, each more pathogenic than the next. E.coli is a group of bacteria, some of which cause diarrhoea, others kidney failure, and still others digest our food. The majority of E.coli strains are harmless, useful and necessary for our normal lives. E.coli is known to have a negative effect on raw milk and raw milk products, causing “early release” in Gouda farmhouse cheese due to an excess of E.coli bacteria in the cheese milk. This is simply because the milking process was not hygienic enough. Furthermore, raw milk and raw milk products must be free of STEC (or EHEC), the shigatoxin-producing E.coli (or Enterohemorrhagic E.coli).
STEC has been critically monitored since the late 1980s for food safety reasons and is now further subdivided (genomically) based on combinations of different genes. Such STEC strains did not exist at the end of the 19th century, and Escherich could not have foreseen that his name would remain associated with warnings, virulence, zero tolerance and, above all, fear of raw milk.
Literature
- Escherich, T. (1886). Die Darmbakterien des Säuglings und ihre Beziehungen zur Physiologie der Verdauung. Enke.
- Friedmann, H. C. (2014). Escherich and Escherichia. EcoSal Plus, 6(1), 10-1128.
