(1) Disinfection is the destruction of pathogenic organisms. It does not
necessarily include the killing of all microbes. A disinfectant is any agent capable of
destroying pathogenic microorganisms.
(2) Sterilization is the elimination of all living microorganisms, both
pathogenic and harmless. Any object or material free of all microorganisms is referred
to as sterile.
microorganisms but which do not necessarily kill them.
(4) Germicides (bactericides) are agents causing the destruction of
microorganisms, both pathogenic and harmless.
(5) Asepsis is the absence of pathogenic microorganisms from a given
object or area.
(6) Contamination is the presence of living microorganisms rendering an
object or material unfit for its intended use.
(7) Bacteriostasis (virustasis) is the condition by which microorganisms are
prevented from multiplying, but in no other way affected.
(8) Sanitization is the reduction in the number of bacteria to a level
prescribed as safe by public health or environmental health authorities.
b. Types of Agents. Agents for sterilizing and disinfecting may be classified as
physical and chemical agents. Specific agents are discussed in paragraphs
3-4 and 3-5.
a. Mechanical Means. Mechanical means may be used to achieve a high
degree of cleanliness and microbe removal, but not to accomplish sterilization.
Mechanical means include the following:
(1) Scrubbing. Scrubbing thoroughly with soap and water, and often with an
additional chemical, removes microorganisms mechanically, while the soap acts upon
(2) Filtration. Filters made of unglazed porcelain, diatomaceous earth,
asbestos, and other porous substances are used to remove microorganisms from fluids.
Sterility mayor may not be achieved, depending upon the microorganisms present. The
smaller viruses and rickettsiae are capable of passing through such filters.