Chapter 11 Important terms

Sterilization

Process that removes all microbes from a material

Microbicidal agent

Agent aimed at destroying a specific group of microorganisms

Germicide

A chemical agent that kills pathogenic microorganisms

Disinfection

Use of physical process or chemical agent to destroy vegetative pathogens

chemical agents targeting cell wall

Becomes fragile and cell lyses, cell membrane loses integrity ( detergents, alcohol)

Chemical agents targeting protein /nucleic acid synthesis and function

Prevention of replication, transcription, translation, peptide bond formation, protein synthesis ( radiation, formaldehyde) - disrupt or denature proteins (alchols, acids, heat)

Factors that affect microbial death

Number of microbes, nature of microbes, temperature and pH of environment, concentration/ dosage of agent, mode of action of agent, presence of solvents, organic matter, inhibitors

Antisepsis

Application of chemical agents called antiseptics directly to exposed body surfaces, wounds, or surgical incisions to destroy or inhibit vegetative pathogens

Decontamination

Procedures are physical, chemical, and mechanical methods that destroy or reduce undesirable microbes in an area, methods include heat, radiation, chemical agents, primary targets are microorganisms that can cause infection or spoilage

Physical methods of control

Temperature, radiation, filtration

Incineration

Flame, electric heating coil, infrared incinerators, ignites and reduces microbes and other substances to ashes and gas

Radiation

Energy emitted from atomic activities and dispersed at high velocity through matter space

Ionizing radiation

Gamma rays, x rays, cathode rays

Noniodizing radiation

ultraviolent (UV) radiation

Filtration

Physical removal of microbes by passing a gas or liquid through filter used to sterilize heat sensitive liquids and air in hospital isolation units and industrial clean rooms

Alcohols 1

Only ethyl and isopropyl are suitable for microbial control

Hydrogen peroxide 1

Colorless, caustic liquid that decomposes into water and oxygen gas, the oxygen forms hydroxyl free radicals which are highly toxic and reactive to cells

Quarternary ammonium compounds ( Quats)

Type of cationic detergent alter the membrane permeability of some bacteria and fungi, but do not kill spores