Preceding the 1854 Broad Street cholera outbreak, physicians and scientists held two competing theories on the causes of cholera in the human body.[6] The London medical community debated between miasma theory and germ theory as two possible causes for the persistent cholera outbreaks in the city. The cholera-causing Gram-negative bacterium Vibrio cholerae would not be isolated until 1854. This finding was not publicized until 1883 by Robert Koch, a German physician and bacteriologist.[7]