Who isolated the tetanus bacillus?

Shibasaburo Kitasato isolated the tetanus bacillus. In 1889, the Japanese bacteriologist succeeded in growing the organism responsible for tetanus in pure culture, building on earlier work by Arthur Nicolaier, who had identified the disease-producing organism in soil and demonstrated its connection with tetanus.

The bacterium is now called Clostridium tetani. It is an anaerobic, spore-forming bacterium, meaning it can survive harsh environmental conditions as dormant spores. When spores enter damaged tissue, especially a deep wound with little oxygen, the bacteria can grow and produce tetanospasmin, the neurotoxin responsible for severe muscle spasms and lockjaw.

Kitasato’s work also contributed to the development of antitoxins. Working with Emil von Behring, he helped demonstrate that blood serum could neutralize bacterial toxins, an important foundation of serum therapy and immunology. Robert Koch was Kitasato’s mentor in Germany, but Koch did not isolate the tetanus bacillus. Nicolaier discovered it, while Kitasato is conventionally credited with its successful isolation in pure culture.