In 1916, against the backdrop of the First World War, a British soldier in an Egyptian hospital recovered from a bout of diarrhoea. More than a century later, scientists have revived a freeze-dried culture of a microbe that infected him — thought to be the oldest publicly available cholera bacterium in existence.
Nicholas Thomson at the Wellcome Sanger Institute in Hinxton, UK, and his colleagues sequenced the genome of NCTC 30, the strain of Vibrio cholerae that was isolated from the soldier and is now stored in a British microbial collection. NCTC 30 lacks the classic toxin needed to cause choleric diarrhoea, but the team found that the microbe’s genes contain instructions for a needle-like structure that projects from the bacterium’s surface. This appendage, which other bacteria use to inject proteins directly into host cells, might have caused the soldier’s symptoms. The researchers also identified genes that would have rendered the bacterium resistant to antibiotics — although penicillin wasn’t discovered until 1928.
Because so few V. cholerae isolates are available from this time period, comparisons between NCTC 30 and pandemic strains could provide valuable insights into their evolution, the authors say.