1.
Agent concentration:: if better or worse-depends
Use 95% solution in lab (ethanol) but ideal is 70% to kill (more effective b/c it has more water) ****but In lab we don't want our bacteria to become resistant so use 95% even though less effective
2.
Alcohols:: Action: denature proteins and disrupt cell membranes, ** Most common;
Use: Disinfectants, antiseptics, and as a solvent in tinctures
*****will not kill endospores or mycolic acid; otherwise works well and doesn't hurt you; Bacteriocidal, NOT endospores-written under use
3.
Aldehydes:: -glutaraldehyde and formaldehyde
Action: denatures proteins
**Most taken off market b/c so toxic b/c of side effects
Nucleic acids: action, high level of activity****
Uses: Bacteriocidal, sporocidal, embalming fluid (underlined in uses), disinfectant
4.
Antimicrobials:: Action: act against cell walls, cell membranes, protein synthesis, and DNA transcription and replication
5.
Chemical Methods of Microbial Control list: Phenol, Phenolics, Alcohols, Halogens, Oxidizing agents, Surfactants, Heavy metals, Aldehydes, Gaseous agents, Antimicrobials
6.
Dessication:: Drying
-Conditions: varies with amount of water to be removed
Use: preservation of food, pastas
7.
Dry Heat: Hot air:: -2 hour at 160 deg C
-1 hour at 171 deg C
Action: denatures proteins, destroys membranes, oxidizes metabolic compounds
Use: sterilization of water-sensitive materials such as powders, oils, and metals
- Hot air used in a lot of cosmetics
8.
Dry Heat: Incineration:: 1 sec at more than 1000 deg C
-USE: sterilization of inoculating loops, flammable contaminated medical waste, and
diseased carcasses
- Bunsen burners: loops turn bright red over 1000 deg
9.
Environment (blood (inactivated), medium (fats), temperature: -not as big of a role as blood or something that is insoluable)-
-environment temp and pH can effect the death of microbes or if the agent will be effective
Ex: warm disinfectants generally work better than cool ones b/c chemicals react faster at higher temps
**Also, effect of heat can also be enhanced by acidic conditions
-Ex: household bleach is more effective at a low pH
10.
Exposure time: how long have to sit
Ex: if it says 10-15 min to sit and you only leave it if only on for 5 will it be as effective? No
**longer exposure times ensure the deaths of more microorganisms but have to weigh consequences with the damage that can occur with longer exposure times to a patient or an object
11.
Filtration:: Filter retains microbes
Action: physically separates microbes from air and liquids
Use: sterilization of air and heat-sensitive ophthalmic and enzymatic solutions, vaccines, and antibiotics; water quality
12.
Freezing:: <0 deg C
Action: inhibits metabolism
Use: long-term preservation of foods, drugs, and cultures
13.
Gaseous agents:: ethylene oxide, propylene oxide, and beta-propiolactone
Action: denature proteins
Level of activity: toxic, explosive, high
Uses: Sterilization of heat- and water-sensitive objects
-ethylene oxide kills all within 18 hrs-equivalent to autoclaving so very effective but have to be careful with them
*very good sterilizer but from a cost production perspective only few companies will use b/c of 18 hr wait time
14.
Halogen :: : Iodine, chlorine, bromine, and fluorine
Action: presumably denature proteins
*******Iodine will not kill endospores (pseudomonas will grow in it)
Use: bacteria, viruses; Disinfectants, antiseptics, and water purification
****Blood will inactivates chlorine
15.
Heavy metals:: -Arsenic, zinc, mercury, silver, copper, etc
Use: fungi and algae; zinc -main one to see for humans (will have zinc or selenium)
Zinc-mouthwashes, (selenium shampoo) head and shoulders/fyi can bath cats and dogs in selenium to get rid of ringworm; selenium-shampoo-selson blue
Silver nitrate cream in newborn baby's eyes to kill gonorrhea but-replaced b/c won't kill Chlamydia so just use one that will work on that and gonorrhea
**still often used in some surgical dressing, burn creams, and catheters
Copper used as an algaecide in fish tanks, swimming pools-interferes with chlorophyll
16.
Ideal Disinfectant: (Don't want it to harm you or your pet; won't kill good bacteria; )
1) Fast acting: time frame
2) Effective on all microbes without destroying tissues
3) Penetrate material without damaging or discoloring
4) Easy to prepare and stable
5) Cheap and easy to obtain and use
6) No odor
17.
Ionizing radiation:: -electron beams, gamma rays, xrays
-seconds to hours of exposure (depending on wavelength of radiation)
Action: destroys DNA
Use: sterilization of medical and laboratory equipment and preservation of food
Gamma rays for anything packaged and dry-ionizing radiation
18.
Lyophilization:: Freeze drying
Minus 196 deg C for a few minutes while drying
Action: inhibits metabolism
Use: long term storage of bacterial cultures
19.
Microbial Death:: Number of org have
Types of microbes (endospores)
Agent concentration:
Exposure time
Environment (blood (inactivated), medium (fats), temperature
20.
Moist heat includes: boiling, autoclaving, pasteurization, and ultrahigh-temp sterilization
21.
Moist heat: Autoclaving:: 15 min at 121 deg C and 15 psi
Use: autoclave: sterilization of medical and laboratory supplies that can tolerate heat and moisture; pressure cooker, sterilization of canned food
22.
Moist heat: Boiling:: 10 min at 100 deg C
***Won't kill endospores and mycobacteria
Action: denatures proteins and destroys membranes
Use: disinfection of baby bottles and sanitation of restaurant cookware and table ware
Freq used method- boiling used a lot
**Boiling time is important!
-disinfects well but says 10 min although often told during boil order 3-5 min-why? Altitude, etc (water boils at lower temps at higher elevations b/c atmospheric pressure is lower-so longer boiling time is req)
***3-5 is only sanitizing it so need 10 min to disinfect!! (not appropriate for sterilization)
23.
Moist heat: Pasturization:: 15 sec at 72 deg C
Use: LOWERS all pathogens and most spoilage microbes in dairy products, fruit juices, beer, and wine
*** lowers all pathogens not destroys! ***
24.
Moist heat: Ultrahigh-temperature sterilization:: 1-3 sec at 140 dec C
USE: sterilization of dairy products (sterilization so can use at room temp and long expiration date)
25.
Nonionizing radiation:: Ultraviolet light
-irradiation with 260 nm wavelength radiation
Action: formation of thymine dimmers inhibits DNA transcription and replication
Use: disinfection and sterilization of surfaces and of transparent fluids and gases
**UV light used a lot underwater if has been contaminated and at water treatment plants/ some pros and cons b/c has to in constant contact can't go too deep
26.
Number of org have: (10 would die sooner than a higher number of cells)
27.
Osmotic pressure:: Exposure to hypertonic solutions
Action: inhibits metabolism
Use: preservation of food- high or low levels of salt in packaging
28.
Oxidizing agents:: Oxidizing agents:
Ex: peroxides, oxone, and peracetic acid)
**Cytotoxic!!! Don't want to touch
***Sporocidal -will kill endospores!!-(use)
Action: denature proteins by oxidation
Use: disinfectants, antiseptics for deep wounds, water purification, and sterilization of food-processing and medical equipment
29.
Oxidizing agents: Ozone:: protective layer; good as an antibacterial; generators that do ozone penetration ex: hot dogs use gas to kill off bacteria on surface; also water and ground meat
30.
Oxidizing agents: Peroxide:: some are resistant to it; will kill off your cells that it comes in contact with; some organisms very effective with; don't want to expose peroxide to air or will deteriorate more quickly)-cheap;-not effective for cleaning wounds b/c our body releases catalase and neutralizes it
31.
Phenol:: carbolic acid
Action: denatures protein and disrupts cell membranes
Used: fungi, viruses
(take level of activity with grain of salt-don't worry about)
(Want: main method; short version of action)
32.
Phenolics:: chemically altered phenol; bisphenols (Lysol) are composed of a pair of linked phenolics (underline bisphenols-lysol)
Use: disinfectants and antiseptics
-triclosan-toys antimicrobial- (embedded in plastic)-no longer very effective chemical agent (also used in toothpaste etc) Not effective b/c kills good bacteria so nothing to outcompete bad bacteria, also cheaper so people will buy, if use directive to kill for purpose ie: clean dirty toilet as opposed to using all the time b/c "antimicrobial";
****Very effective on viruses, fungi: Trichophyton rubrum: most common cause of ringworm, jock itch and althlete's foot
Use: Staphylococcus aureus:
33.
Physical Methods of Microbial Control list: -Moist heat, Refrigeration, Freezing, Desiccation, Lyophilization, Filtration, Osmotic pressure, Ionizing radiation, and Nonionizing radiation
34.
Quaternary Ammonia Compounds:: more common seen as use
- consumer things you can buy: ear piercing kits, mouthwashes, some of hand foamers, floor disinfectants , cheap and easy to use;
****no mechanical action-is using ammonia to actually kill
USE: disinfectants and treatment of infectious disease
35.
Refrigeration:: 0-7 deg C
Action: inhibits metabolism
Use: preservation of food
36.
Relative susceptibilities of microbes to antimicrobial agents:: Most easily killed vs. those that will be most diff to kill
-Least to most susceptible:
• Viruses most susceptible: (nonenveloped-without an envelope-membrane)
• Gram positive bacteria: susceptible b/c of peptidoglycan wall
• Fungi : fungi infections are being difficult now
• Gram negative bacteria
• Cysts of Protozoa
• Mycobacteria
• Bacterial endospores: Bacillus and Clostridium -b/c of endospores
37.
Surfactants: soaps and detergents
Action: -decrease surface tension of water and disrupt cell membranes
- mechanical- have to rub to get out
-nontoxic, noncorrosive
Use:
Staphlococcus, Micrococcus, Neisseria-why use time frame with washing hands to ensure effectiveness-rub it off b/c of mechanical action
-Soaps: degerming, detergents: antiseptic
38.
The relationship between temp and pressure:: ***Note that higher temps (which causes greater antimicrobial action)>>>associated with higher pressures
39.
Types of microbes (endospores): both endospores and mycobacterium will decide if will be susceptible to whatever concentration you are using (also cysts of protozoa-the wall of the cyst prevents entry of most disinfectants, protects against drying, and shields against radiation and heat)
40.
What cell structures do antimicrobials target?: 1) Proteins (denatured)
2) Membranes (surfactants)
3) Nucleic acids (alkylating agents)-DNA compounds
4) Cell walls (crystal violet)
5) Energy production (lactic acid) (metabolic pathways)
41.
What determines if an agent will be effective?: 1) Time
2) Temp
3) pH
4) Concentration
