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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 :
- cell Membrane
- 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.
- From cresol
- 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.
Surface-active agents (Surfactants) :
ACID-ANIONIC SURFACE ACTIVE SANITIZERS
QUATERNARY AMMONIUM COMPOUNDS
- microbes to be mechanically removed. Breaks up the oily film that covers skin and allows microbes and dirt to wash away.
- (anion) reacts with the plasma membrane of microbes to degrade it.
- has cation charge and less effective against gram-negative, endospores, tuberculosis bacteria. Can kill fungi, amoebas, and some viruses.
Chemical Food preservatives :
Used for what?
What happens to what when exposed to what?
- used to retard spoilage, and are believed o be safe for consumption.
- Sodium nitrate added to meat like bacon and hot dogs to prevent.
- Obligate aerobes die in presence of sodium nitrite.
What type of gas can be used as a disinfectant?
What is it?
What’s use for viruses, endospores and TB?
Why is drinking moonshine bad?
- Formaldehyde gas
- - Formalin, a 37% aqueous solution, preserve biological specimen.
Gaseous Chemical Sterilants :
What does ethylene oxide do?
Requires and can be used as?
- kills all microbes and endospores.
- Highly toxic and explosive.
- Requires long soaking times and can be used for things not autoclaved like mattresses.
Plasma Sterilization :
How does it work?
What is it used for?
Is it expensive?
- 4th state of matter in which gas is excited by EM filed, creation a mixture of positive and negative particles.
- sterilize things like long hollow tubes.
What are they?
What does Hydrogen peroxide help do?
What about Benzoyl Peroxide?
- oxidizing agents — these oxidize cellular components of microbes.
- Hydrogen peroxide helps release O2 and makes conditions bad for anaerobic bacteria.
- Benzoyl Peroxide : main ingredient in many acne treatments and may be used in treating wound infections caused by anaerobes.
- H2O2 -> H2O + O2 attacks S. Acne
- the study of heredity, how genes carry information, replication, and passage to subsequent generation.
- Collection of genetic material within a cell or organism.
- segments of DNA that code for functional product (proteins), except viruses. Some are made from RNA.
How does low fidelity benefit a microbe/bacteria?
- Increases the rate for mutation. This causes resistance to antibiotics and even viruses can evade form immune system.
A topoisomerase is used on eukaryotic cells. What about prokaryotic?
- Use Gyrase.
Genetic transfer ONLY in Bacteria - Difference between :
- introducing brand new genes into the bacteria.
- transfer of DNA genetic material. Uses pilli.
- - passing DNA from one bacterium to another using a virus as a carrier.
Go into more detail Lecture 10 #20-33
What's spontaneous mutation?
- any agent (chemical or radiation) that brings about mutation.
- Spon. Mutation : absence of any mutation causing agent, there is a base change. Typically occurs as abase pair substitution (frame shift).
- Harmful : changes in DNA that cause errors in the protein sequence, creates partially or completely non-functional proteins.
- Lethal : Changes in DNA that cause errors in the protein sequence, yields a non-functional protein.
- Beneficial : changes in the DNA that causes errors in the proton sequence. Yields a functional proteins that helps in survival.
What’s nucleoside analog?
What’s AZT and Aflatoxin-apergillus flavus?
- similar to nucleotide base but chemically different.
- AZT : used as an antiviral drug to treat HIV
- Aflatoxin : mold found on peanuts and are frameshift mutagen.
What does Ionizing Radiation do to DNA? Examples?
- free radicals combine with DNA and induces base changes.
- ex: x-Rays and Gamma rays and causes free radicals (molecules with unpaired electrons) to form.
What is added to find the complementary DNA?
This relies on 2 things…?
- Strands of DNA serve as a template and primers, nucleotides, and Taq polymerase added.
- Makes billions of copies of DNA.
- 1. polymerase being bale to stand the high temp. to synthesize DNA.
- 2. Primers are made specific to the DNA of the microbe one wants to detect.
DNA Vaccines :
What is it?
What does it do?
How does it do this?
- use of plasmids (clones and grown in bacteria) with a viral gene under the control of a human promoter.
- Produces an immune system réponse against invaders like HIV, Influenza and malaria.
- Manipulates plasmids in the lab with restriction enzymes to cut and paste DNA into plasmids.
Gene therapy :
What is it?
What can be added to treat cancer cells?
What types of virus does it use?
- removal of certain cells and addition of defective or missing gene back into patient. Cells can then function normally when placed back into humans.
- Uses lenti- and retro- viruses.
General Characteristics of a Virus :
Type of cell?
Does not have…?
Why is it important.
Where can the virus attach to?
- no ribosomes (can’t protein synthesize), ATP generating system, nucleic acid replication.
- Antivirals interfere with protein synthesis and DNA/RNA replication.
- specific receptors on cell wall, flagella and fimbraie.