Kitasato, Shibasaburō (1852–1931)

Japanese bacteriologist who discovered the plague bacillus while investigating an outbreak of plague in Hong Kong. He was the first to grow the tetanus bacillus in pure culture. He and German bacteriologist Emil von Behring discovered that increasing nonlethal doses of tetanus toxin give immunity to the disease.

Kitasato was born on the island of Kyushu and studied at Kumamoto Medical School and Imperial (now Tokyo) University. In 1885 he was sent by the government to study bacteriology in Germany and went to work in the laboratory of Robert Koch in Berlin. On his return in 1891, Kitasato set up a small private institute of bacteriology. When this was incorporated into Tokyo University against Kitasato's wishes in 1915, he resigned and founded the Kitasato Institute, which he headed for the rest of his life.

Having made the discovery of antitoxic immunity in 1890, Kitasato and von Behring rapidly developed a serum for treating anthrax. After returning to Japan, Kitasato was sent by his government to Hong Kong in 1894 to investigate an epidemic of bubonic plague. France also sent a small research team, led by Swiss bacteriologist Alexandre Yersin. The two teams did not collaborate because of language difficulties and there is some doubt whether it was Kitasato or Yersin who first isolated Pasteurella pestis, the bacillus that causes bubonic plague, but Kitasato published his findings first. The bacillus is now known as Yersinia pestis.

Kitasato also isolated the causative organism of dysentery in 1898 and studied the method of infection in tuberculosis.