Botulinum toxin
In 1895 (seventy-five years later), Émile van Ermengem, professor of bacteriology and a student of Robert Koch, correctly described "Clostridium botulinum" as the bacterial source of the toxin. Thirty-four attendees at a funeral were poisoned by eating partially salted ham, an extract of which was found to cause botulism-like paralysis in laboratory animals. Van Ermengem isolated and grew the bacterium, and described its toxin, which was later purified by P Tessmer Snipe and Hermann Sommer.
AB5 toxin
This family is also known as Ct or Ctx, and includes the heat-labile enterotoxin family, known as LT. Cholera toxin’s discovery is credited by many to Dr. Sambhu Nath De. He conducted his research in Calcutta (now Kolkata) making his discovery in 1959, although it was first purified by Robert Koch in 1883. Cholera toxin is composed of a protein complex that is secreted by the bacterium "Vibrio cholerae". Some symptoms of this toxin include chronic and widespread watery diarrhea and dehydration that, in some cases, leads to death.