2. CONTROL OF MICROORGANISMS Flashcards
→ complete removal or destruction of all forms of life, including bacterial spores
→chemical or physical methods
Sterilization
→process that eliminates a defined scope of
microorganisms
→process of killing or removing microorganisms in inanimate surfaces thru the use of chemical agents
Disinfection
→free of life of every kind
Sterile
→destroys pathogenic organisms, but not necessary all microorganisms or spores
→most are chemical substances
Disinfection
→having the property of inhibiting bacterial growth or multiplication
Bacteriostatic
→having the property of killing or destroying bacteria
→precipitates bacterial protein (H2SO4, HCl
Bactericidal
→chemical substance used to kill infection producing microorganisms on surface but too toxic to be applied directly on tissues
Germicide or Disinfectant
→characterized by the presence of pathogenic
microbes in living tissue
Septic
→characterized by the absence of pathogenic
microbes
Aseptic
→chemical substance which opposes sepsis or putrefaction either by killing microorganism or preventing their growth
→applied topically to living tissues
Antiseptic
Examples of Antiseptic
Phisohex, Hexachlorophene, Tincture of Iodine/Povidone Alcohol (Iodophore)
→time in minutes to reduce the bacterial population or spores by 90% at a specified temperature
Decimal Reduction Time (DRT/D/D)
Factors That Influence the Degree of Killing Microorganisms
a. Types of organisms
b. Number of organisms
c. Concentration of disinfecting agent
d. Presence of organic material
e. Nature of surface to be disinfected
f. Contact time
g. Temperature
h. pH
i. Biofilms
j. Compatibility of disinfectants and sterilants
Types of ORGANISMS!
✓Bacterial spores→ resistant
✓Acid-Fast Bacilli
✓Nonenveloped viruses
✓Vegetative bacteria
✓Enveloped viruses
→ most resistant to the actions of heat, chemicals, and radiation
→naked pieces of protein without nucleic acid
Prions
degenerative diseases of the nervous system (transmissible spongiform encephalopathy—mad cow disease)
Creutzfeldt-Jakob disease
blood, mucus, and pus
organic materials
at least 1 to 2 minutes to kill microorganisms
Alcohol and Iodine preparations (Betadine)
Most Resistant → Least Resistant organisms
Prions → Bacterial spores → Mycobacteria → Nonlipid viruses → Fungi → Bacteria → Lipid viruses
PHYSICAL METHODS
Heat
Low/Cold Temperature
Desiccation and Lyophilization
Filtration
Radiation
→most common method used for the elimination of microorganisms
→most reliable and universally applicable method of sterilization
Heat
→kills microorganisms rapidly than dry heat
→Lethal effect is attributed to DENATURATION and COAGULATION of protein and DEGRADATION of nucleic acid
Moist Heat
→fastest and simplest physical method of sterilization
→sterilization method of choice for heat-stable objects
Moist Heat
→ surgical instruments, needles, hypodermic syringes, rubber stoppers
→kills all vegetative organism but not all spores or viruses
Boiling