Bacteria from First World War soldier revived and sequenced by Wellcome Sanger Institute
Bacteria isolated from the stool of a British soldier who fought in the First World War has been revived and sequenced.
Wellcome Sanger Institute scientists read the genetic code of what they believe is the oldest publicly-available strain of the bacterial species Vibrio cholerae, which leads to cholera.
The researchers say the work improves our understanding of the evolution of the disease, which is caused by consuming contaminated food or water.
The findings, published in Proceedings of the Royal Society B, show the unique, non-toxigenic strain is distantly related to those strains of bacteria that have caused cholera pandemics, but not capable of causing one itself. It was also unrelated to the classical V. cholerae that caused the sixth pandemic in the war.
The strain had been extracted in 1916 from the stool of a British soldier convalescing in Egypt. The isolate was taken from ‘choleraic diarrhoea’, according to reports at the time, and then stored and deposited in the National Collection of Type Cultures in 1920.
Professor Nick Thomson, lead author from the Wellcome Sanger Institute, said: “We have decoded the genome of what we believe to be the oldest archived ‘live’ sample of V. cholerae. It is a privilege to be able to look at the genome of this isolate.
“Studying strains from different points in time can give deep insights into the evolution of this species of bacteria and link that to historical reports of human disease.
“Even though this isolate did not cause an outbreak it is important to study those that do not cause disease as well as those that do. Hence this isolate represents a significant piece of the history of cholera, a disease that remains as important today as it was in past centuries.”
Matthew Dorman, first author from the Sanger Institute, added: “Reports in the literature indicated that there was something unusual about the strain of bacteria from the WWI soldier.
“It’s promising to see that our genomic information aligns with those historical records. We also made other observations – under the microscope, the bacterium looks broken; it lacks a flagellum – a thin tail that enables bacteria to swim. We discovered a mutation in a gene that’s critical for growing flagella, which may be the reason for this characteristic.”
Researchers found the strain of V. cholerae possessed a gene for ampicillin resistance - adding to mounting evidence that genes for antibiotic resistance existed in bacteria prior to the introduction of antibiotic treatments.
This may have been because the bacteria needed protection against natural antibiotics.
Julie Russell, head of culture collections at NCTC, said: “The National Collection of Type Cultures grows and maintains over 5,000 strains of bacteria from the last hundred years or so. Studying these bacteria offers a window into the past and helps scientists to understand how bacteria evolve over time, and the roles they played in history.”