Researchers map the genetic code of 102-year-old strain of cholera

Scientists in the U.K. have sequenced the genome of what they believe is the oldest sample of Vibrio cholera, the bacterium that causes cholera. This cholera strain — which was extracted in 1916 from the stool of a World War I soldier who was recovering from cholera in Egypt — lacked a phage, or virus, containing genetic material that the cholera bacteria use to make a deadly toxin. Although there was a cholera pandemic happening concurrently with the first World War, the absence of this phage led researchers to believe that this particular strain of cholera was unlikely to have caused the pandemic. Scientists also found that this strain of Vibrio was resistant to the antibiotic ampicillin, which was introduced commercially 40 years after World War I. This finding, according to the authors, provides further evidence that antimicrobial resistance genes predate the introduction of antibiotics.