Koch's postulates
Germ theory criteria
Koch's postulates are a set of four criteria established in the late 19th century to determine whether a specific microorganism causes a particular disease.
The postulates require that the organism be found in all cases of the disease, isolated and grown in pure culture, reproduce the disease when introduced into a healthy host, and then be re-isolated from that host.
These principles became foundational to germ theory and medical microbiology, though modern understanding recognizes exceptions for organisms that cannot be cultured or diseases with multiple causes.
Complete separation from others
- inoculationInjection conferring disease resistance
- reproducibilityAbility to repeat findings
- causationProduction of effects
- experimentalTesting new methods
control group · confirmation · verification · criteria · laboratory · systematic approach · germ theory · evidence
Capacity to cause disease
- hostOne receiving guests
- specificityExactness of detail
- etiologyScience of disease origins
- pathogenDisease-causing microorganism
disease · symptoms · transmission · infection · carrier · vector · susceptibility · immunity
Mycobacterial lung disease
- anthraxSpore-forming bacterial disease
- choleraBacterial disease causing fatal dehydration
- nineteenth centuryYears 1801-1900
- golden agePeriod of peak prosperity
Louis Pasteur · germ theory · Nobel Prize · Berlin · microscopy
Territories under foreign control
- petri dishLidded laboratory culture container
- microbial growthOrganisms multiplying microscopically
- stainingApplying dye or pigment
- microscopeInstrument for viewing minute objects
morphology · Gram-positive · Gram-negative · incubation · antiseptics · streak plate · microorganism · bacillus
isolation
Complete separation from others
- inoculationInjection conferring disease resistance
- reproducibilityAbility to repeat findings
- causationProduction of effects
experimental · control group · confirmation · verification · criteria · laboratory · systematic approach · germ theory · evidence
virulence
Capacity to cause disease
- hostOne receiving guests
- specificityExactness of detail
- etiologyScience of disease origins
pathogen · disease · symptoms · transmission · infection · carrier · vector · susceptibility · immunity · lesions
tuberculosis
Mycobacterial lung disease
- anthraxSpore-forming bacterial disease
- choleraBacterial disease causing fatal dehydration
- nineteenth centuryYears 1801-1900
golden age · Louis Pasteur · germ theory · Nobel Prize · Berlin · microscopy
colonies
Territories under foreign control
- petri dishLidded laboratory culture container
- microbial growthOrganisms multiplying microscopically
- stainingApplying dye or pigment
microscope · morphology · Gram-positive · Gram-negative · incubation · antiseptics · streak plate · microorganism · bacillus · cultivation
- German MedicinePaul Ehrlich, germ theory, aspirin, Bayer, Merck
- disease causesetiology, causation, pathogens, genetics, infection
Koch's postulatescorrelation
Statistical relationship measure
association · clinical observation · anecdotal evidence · speculation · conjecture
Koch's postulatesspontaneous generation
Life arising from nonliving material