Lesson 13: CONTROL OF MICROORGANISIMS Flashcards
Two goals of controlling microorganisms
a. to destroy pathogens and prevent their transmission and
b. to reduce or eliminate microorganisms responsible for the contamination of water, food, and other substances.
a process by which an article, surface, or medium is freed of all living microorganisms either in the vegetative or in the spore state.
Sterilization
Microorganisms are controlled
either by
a. physical agents (temperature, desiccation, osmotic pressure, radiation, and filtration)
b. chemical agents (disinfectants, antiseptics, antibiotics, and chemotherapeutic antimicrobial chemicals)
any material that has been subjected to sterilization
Sterile
a chemical agent that is used to perform sterilization because of their ability to destroy spores
Sterilants
: also called a microbicide, is any chemical agent that kills pathogenic microorganisms either on inanimate (nonliving) materials or on living tissue but not resistant microbial
Germicide
the use of a chemical agent that destroys or removes all pathogenic organisms or organisms capable of giving rise to infection or its harmful products (toxin) thus destroys vegetative pathogens but not bacterial endospores. Used only on inanimate objects because they can be toxic to human and other animal tissue, when used in higher concentrations.
Disinfection
is defined as the growth of microorganisms in the body or the presence of microbial toxins in blood and other tissues.
sepsis
refers to any practice that prevents the entry of infectious agents into sterile tissues and thus
Asepsis
are chemical agents applied directly to the exposed body surfaces (e.g., skin and mucous membranes), wounds, and surgical incisions to destroy or inhibit vegetative pathogens.
Antiseptics
a process usually involves scrubbing the skin or immersing it in chemicals, or both. It also emulsifies oils that lie on the outer cutaneous layer and mechanically removes potential pathogens from the outer layers of the skin.
degerming/Antisepsis
a compound (e.g., soap or detergent) that is used to perform sanitization. Air sanitization with ultraviolet lamps reduces airborne microbes in hospital rooms, veterinary clinics, and laboratory installation.
Sanitizer
is any cleansing technique that mechanically removes microorganisms (along with food debris) to reduce the level of contaminants.
Sanitation
Examples of degerming procedures are
a. surgical hand scrub
b. application of alcohol wipes to the skin, and
c. cleansing of a wound with germicidal soap and water.
Methods of controlling microorganisms
- Sterilization
- Disinfection
- Antimicrobials
Physical methods of sterilization
- Sunlight
- Heat
- Filtration
- Radiation
- Sonication
STERILIZATION
Classified into:
- Physical methods
- Chemical
a natural method of sterilization of water in tanks, rivers, and lakes. It has an active germicidal effect due to its content of ultraviolet and heat rays. Bacteria present in natural water sources are rapidly destroyed by exposure.
Sunlight
one of the most dependable method of sterilization. As a rule, higher temperatures (exceeding the maximum) are microbicidal, whereas lower temperatures (below the minimum) tend to have inhibitory or microbiostatic effects.
Heat
Rule of temperature
Higher is microbicidal while lower have inhibitory or microbiostatic effects.
Two types of sterilization
Moist and dry
occurs in the form of hot water, boiling water, or steam (vaporized water) and the temperature usually ranges from 60 to 135°C. Moist heat kills microorganisms by denaturation and coagulation of proteins.
Moist heat sterilization
Moist heat sterilization temperature usually ranges
from 60°C to 135°C
Classification of moist heat:
- Sterilization at a temperature below 100°C
- Sterilization at a temperature of 100°C
- Sterilization at a temperature above 100°C
- Intermittent sterilization