The bacteria that caused a severe diarrhea in a soldier of the British Empire in the First World War (IGM) have just come back to life. A group of British scientists has resurrected and cultivated them. The sequencing of its genome shows that the bacteria that made that military man sick is different from those that have caused the last cholera pandemics, he already had resistance to antibiotics and has mutated in all this time that has been saved.
The soldier, of whom there are no records of his name and rank, fell ill in 1916, being on the eastern front. While convalescing in a military hospital in Alexandria (Egypt), they took samples of their feces, isolating bacteria of the species Vibrio cholerae, the cause of cholera. Preserved freeze-dried (dehydrated by freezing), since 1920 they are part of the National Collection of Crops Type (NCTC, for its acronym in English), a British public repository with 5,100 bacterial strains. The one of this soldier is one of the most veteran and oldest of those of the sort Vibrio.
Now, microbiologists from the Wellcome Sanger Institute and British public health have recovered, thawed and cultivated a portion of the samples. Once the colony was enlarged, the researchers could analyze them more closely and sequence their genome and compare it with that of 200 other strains, a comparison that has thrown more than one surprise.
The results, published in Proceedings of the Royal Society B, show that this old strain is still a V. cholerae, it is very far from the two varieties (serotypes) that have caused all the cholera pandemics since 1800, including the sixth pandemic, which only during the IGM ended with tens of thousands of soldiers, especially the central powers. Although it lacks the genes that code for the cholera toxin, it does have isolated pathogenic elements, which could have caused the diarrheal process of the soldier.
"Even though this sample will not cause an outbreak, it is important to study both those that cause diseases and those that do not," says the molecular microbiologist at the Wellcome Sanger Institute and senior author of the study, in a note. Nicholas Thomson. "That's why, this isolated [muestra tomada del ambiente] It represents an important part of the history of cholera, a disease that continues to be as important today as it was in previous centuries, "he adds.
The authors believe that it is about the sample live of the oldest bacteria of which there is evidence. Called NCTC 30, for occupying that position in the order of the file, is the only one taken from the barely 2,500 British soldiers who fell ill with cholera during the entire war, a figure much lower than those that affected the Austrian, German and Ottoman soldiers.
Its genetic code reveals that it is not related to the strains that cause the last pandemics
Also, NCTC 30 is quite a rarity. It develops without the characteristic bacterial flagellum, a single appendix that gives its motility to the bacteria. In fact, when viewed under the microscope, the bacteria do not move. "We have discovered a mutation in a gene that is critical for the development of the flagellum, which could explain it," says the researcher at the Wellcome Sanger Institute and co-author of the work, Matthew Dorman. The soldier's bacteria did have the scourge, so it must have been lost since then.
NCTC 30, or Martin 1, as it had been identified by isolating it from the soldier, which may have been so called, still has one last surprise. Obtained in 1916, among its genes there are some that code to defend against ampicillin, an antibiotic. That is, more than a decade before Alexander Fleming will come across penicillin, this strain had already developed resistance to antibiotics. This finding confirms, for the authors, that bacteria carry their whole lives defending themselves from other microorganisms.