Sterilization vs Disinfection :
Define Sterilization and Disinfectant and Antiseptic.
Sterilization : destroys all forms of life.
Disinfectant : antimicrobial agent used on inanimate objects.
Antiseptic : used on living tissue.
Bacteria -Cidal vs. -Static :
bacteriacidal : Kills bacteria
Bacteriastatic : Inhibits bacterial growth
Factors that effect Antimicrobial Activity :
- Time, temp, concentration of antimicrobial agent, type of microbe, activity of microbes and presence of organic matter.
Targets of antimicrobial agents :
enzyme and proteins
DNA and RNA
Physical Methods of Microbial Control :
Heat : works by denaturing enzymes and proteins.
a. Thermal Death Point (TDP) : lowest temp. at which all microorganism in a liquid culture are kille din 10 minutes.
b. Thermal Death Time (TDT) : minimum length in which all microorganisms in a liquid culture are killed at a given temperature.
Moist Heat :
What does boiling water do?
What is not effective against?
What’s the most preferred method of sterilization?
When does water boil and increase of what increases what?
What degree/time is good enough to sterilize everything?
Boiling water : Kills vegetative bacterial cells, Fungi and many viruses. Not effective for endospores and some viruses.
Autoclave : preferred method of sterilization. Water boils at 100*C and increasing the pressure increases the temperature.
121*C for 15 min is good enough to sterilize everything.
What is it?
What’s the high temp/ short time pasteurization?
What does it do and give some examples?
Mild heating sufficient to kill microbes that cause food spoilage.
High temp short time pasteurization is 72*C for 15s
Increases the life of most food products. Ex : canned foods, creams and etc.
Kilit Ampule :
What is it?
What’s the pH indicators?
What happens when a bacteria is able to ferment the sugar?
Spores of Bacillus stearothermophilus. (Heat loving) Fermentable sugar.
pH indicator : basic = red and acid = yellow.
the pH indicator would turn yellow.
Dry Heat :
What are the 3 methods and what do they use?
1. Direct Flaming : Inoculating Loop and Needle 100% effective.
2. Incineration : disposable wastes (paper cups, bags and dressings.)
3. Hot Air sterilization : Oven (170 C for 2 hours). Used on substances what would be damaged by moist heat sterilization. (Gauzes, dressings or powders.
What is it?
Removes microorganisms from solutions that might be damaged by heat.
Culture media, enzymes, vaccines and antibiotics.
What are the 2 types?
What do they use and the substances that could be damaged by the heat?
What’s thymine Dimers?
1. Ionizing Radiation (short wavelength more energy) Gamma rays and x-rays which penetrates most substance.
Used on substances that coul deb damaged by heat.
Ex : plastic petri dishes, plastic syringes, catheters, surgical gloves.
2. Non-Ionizing Radiation uses UV light (does not penetrate plastic, glass or proteinaceous matter. Used to reduce microbial populations in hospital rooms, nurses and operating rooms.
- a form of DNA
How do many of the disinfectants work by?
Destroys the PM integrity and results in the cell leakage.
Degrades the cell surface proteins.
How does it work?
Derived from waht?
What ingredient makes lysol and what do phenols work well with?
Works by injuring lipid-containing plasma membranes and causing cell leakage.
O-phenolphenol is the main ingredient in Lysol. Works really well on Mycoplasma tuberculosis and M. Leprosy
What type of group does it contain?
Used as what?
contains 2 phenol groups.
used as lotions to control gram (positive and negative.)
Soluble in plastics. Can be made into antimicrobial plastics.
Triclosan-bisphenol incorporated into many products like cutting boards, calculators and knife handles.
Inhibits fatty acid synthesis and prevents formation of lipid base cell wall.
Bacteria start to become more resistant to these products and etc.
What’s an example?
What is it and what does it do?
Similar to phenolics but are less toxic.
Disrupts the plasma membrane. Excellent as surgical scrubs and for patient preps, irritant to the eyes.
How is it special?
How does it work against and inhibits what?
One of the oldest methods around.
Works against all bacteria and many endospores, fungi and viruses.
Inhibits the functions of microbial proteins and alters plasma membrane.
Tincture - iodine combined with alcohol.
Iodophor - iodine combined with an organic carrier molecule. Betadine.
What does it do?
How does it do it?
Kills bacteria and fungi but not endospores and most viruses.
Denaturing proteins, but disrupts membranes and dissolves lipids (fats).
Biological organic material allows the protection of bacteria. ex: poooop.
Heavy Metals :
What happens to them at low concentrations?
What does silver nitrate do?
How does Mercury and Zinc relate to this?
works to denature proteins, including enzymes.
Silver Nitrate : used to treat eye infections in newborns caused by gonorrhea.
Mercury : used to keep vaccines sage from contamination.
Zinc : in cough drips : distrips the enzyme in the viruses.